List of Teenage Mutant Ninja Turtles (2012 TV series) characters
This is a list of characters from Teenage Mutant Ninja Turtles, an American animated series based on the eponymous franchise that premiered on September 29, 2012 on Nickelodeon in the United States and that premiered on YTV in Canada.
- 1 Main characters
- 2 Villains
- 3 Supporting characters
- 4 TV show characters
- 5 References
The Teenage Mutant Ninja Turtles are a team of humanoid mutant red-eared slider turtles who were hidden ever since their mutations within the sewers of New York City and usually go up to the surface only in the night time.
- Leonardo / "Leo" (voiced by Jason Biggs in season 1 and most appearances in season 2, Dominic Catrambone in various episodes of season 2, Seth Green in season 3) - Leonardo is an enthusiastic ninjutsu student, learning how to be an effective leader for his three often unruly brothers. He wears a blue mask and fights with two katana swords called Niten Ryu. Aside from his sensei, he takes leadership references from his favorite sci-fi cartoon series Space Heroes which annoys his brothers to no end, but also gives vital plot points to an episode. In this incarnation, his skin seems darker than his brothers'. Leo drives the Shellraiser. In "Fungus Humungous," Leo's biggest fear is losing his team and getting blamed for failure. In "The Invasion," Shredder says that Leo is overconfident. Despite this, he is able to defeat multiple Foot Bots as well as Tiger Claw, Rahzar, and Fishface before Shredder knocks him out with one hit leaving him with many cracks in his shell, many bruises, and leaving him unconscious. At the end, his brothers, April, and Casey try to heal him as they travel upstate in the Party Wagon. In "Within the Woods," Leo finally regains conscious in the bathtub at the O'Neil family house, but the reason his voice sounds different is because he sustained damage to his throat from his previous fight with the Foot Clan. He is able to recover from some of his injuries and help the Turtles, April, and Casey defeat Creep. He is still recuperating from his remaining injures as he is seen using a crutch in later episodes. In "Vision Quest," Leonardo overcomes his injury during a spirit quest that involved him fighting a spirit version of Shredder. In "Return to New York," he fights Claw Shredder. In "Serpent Hunt," the Turtles are looking for Karai who is hunted by Ivan Steranko and Anton Zeck. After Karai is captured by the duo, Turtles arrive to the docks where they confront Shredder. In "The Pig and the Rhino," Leo and Mikey are looking for Karai in Coney Island park of attractions. Soon Bebop and Rocksteady arrive, holding Raph, Donnie, April and Casey as hostages. When everyone is released, Leo, Raph and Mikey fight Rocksteady on Comet roller coaster. In "Battle for New York" Pt. 1, he doesn't trust Slash who formed his own team - the Mighty Mutanimals. Leo refuses to work with Slash but two teams are attacked by the Kraang and they have to delay the discussion. Leo fought Krang Sub-Prime in Technodrome during the rescue mission. In the end of the episode he and Slash finally manage to improve their relationship.
- Raphael / "Raph" (voiced by Sean Astin) - Raphael often lets his impulsiveness get in the way of rational thought. He wears a red mask and fights with two sai. While hot-headed, he has a soft side, as demonstrated by his interactions with his pet turtle Spike. But when Spike is mutated into Slash, Raph loses the only thing he could share his "deep thoughts" with. This incarnation of Raphael is depicted with a lightning bolt-shaped crack in his upper left plastron. Raph is in charge of the Shellraiser's weapons systems. In "Cockroach Terminator," it is revealed that Raph is afraid of cockroaches until he managed to defeat the mutant cockroach Spy-Roach. However in "Fungus Humungous," Raph is still afraid of Spy-Roach. In "The Invasion," Raph brings a photo of Spike as the one thing to save from the lair before it is destroyed and hopes that Slash survives the invasion of the Kraang. In "Within the Woods," he is seen sitting near Leo who remains unconscious for three months. Later in this episode he is mutated by the Creep. In the end of the episode he is brought back to normal by Donnie. In "Buried Secrets," Raph, April and Casey fight with the Mom Thing who already absorbed Mikey, Donnie and Leo. In "Vision Quest," Raph fights spirit vesion of Fishface. In "Return to New York," he fights Shiva Shredder. In "Serpent Hunt," the Turtles are looking for Karai. In "The Pig and the Rhino," Raph and Casey are defeated by Rocksteady near the Argosy Theater. Later, Leo, Raph and Mikey fight Rocksteady on Comet roller coaster. In "Battle for New York," the Turtles meet the Mighty Mutanimals. Raph is trying to convince Leo and Slash that they should work together. In "Casey Jones vs The Underworld," the Turtles and Splinter return to their lair and they start to clear up the mess. Later, Raph departs to the docks after receiving a message from Casey. He arrives just in time to knock out Rahzar and Fishface who were attacked by Casey. During the infiltration on Auman Chemicals, Raph fights Tiger Claw. In "Clash of the Mutanimals," Raph is captured by a mind-controlled Slash and Rockwell. He is brainwashed and fights alongside the Shredder until Leo manages to drive him mad and that causes Raph to vomit the mind-controlling worm.
- Michelangelo / "Mikey" (voiced by Greg Cipes) - Michelangelo is a lover of video games, skateboarding, pranks and pizza. He is also the silliest of the turtles and wears an orange mask and fights with two nunchaku which convert into kusarigama via a blade inside of one of the sticks of each nunchaku and extra lengths of chain stored in the other. Mikey has a great skill of water balloon launching which could have defeated the Shredder if Karai did not interfere. Mikey's lack of intelligence is constantly used by his brothers. He was used as bait for mutant Kirby in a costume which he named "Tur-fly-tle". Despite possessing a childlike innocence, he always brings his best game to a fight. Mikey is in charge of navigating the Shellraiser and is also the one that discovered the anime Super Robo Mecha Force Five. In "Fungus Humungous," Mikey's worst fear is Squirrelanoids. In "Into Dimension X," Mikey runs into a portal leading into Dimension X to save Leatherhead. He is seen hours later with a Kraang skull on his head, and exploding rocks on his belt. Mikey somehow gains all the needed intelligence to survive in Dimension X and manages to save Donnie a power cell for his Turtle Mech. In "The Invasion," Mikey brings Ice Cream Kitty and stores her in between frozen pizza boxes to keep her cold. In "Within the Woods" he takes care over the chickens. In "A Foot Too Big," he, Donnie and Raph meet Bigfoot, after a brief fight they take her to their home. After Big Foot is captured by Finger, Mikey and Donnie fight him. In "The Croaking," he meets and befriends Napoleon Bonafrog. In "Vision Quest" we see him fighting with spirit version of Rahzar. In "Return to New York," Mikey knocks out Stockman-Fly and accidentally pushes the alarm button. In "The Pig and the Rhino," Leo and Mikey check Comet roller coaster on Coney Island. There they find Karai but then Bebop and Rocksteady arrive, keeping Raph, Donnie, April and Casey as hostages. Mikey tries to distract the duo by giving them mutant names. Later Leo, Raph and Mikey take on Rocksteady. In "Battle for New York" Pt. 1, he is happy to meet Leatherhead again. Mikey and Leatherhead are the only members of their teams who do not argue with each other. In the Dimension X, Mikey obtains his equipment and becomes Savage Mikey. He hacks Technodrome and drives it during the rescue mission while doing something to get the Technodrome to work on retro-mutagen. In "Casey Jones vs. the Underworld," he fights Rahzar in Auman Chemicals factory.
- Donatello / "Donnie" (voiced by Rob Paulsen) - Donatello is in charge of the design and manufacture of all of the tools and weapons in the Turtles' arsenal. He is also a gifted hacker. He wears a purple mask and fights with a rokushakubo which converts to a naginata via a blade inside one end of the staff. He also has a crush on April, which his brothers all tease him about. This incarnation of Donatello is depicted with gap teeth. Rob Paulsen had previously voiced Raphael in the original 1987 TV series. Donnie is in charge of maintaining the Shellraiser's systems, and using its on-board laboratory. In the second season, he and Casey Jones are in a rivalry due to them both having a crush on April. In "Fungus Humungous," Donnie's worst fear is April hating him. In "Into Dimension X," Donnie struggles to find a power source for the Turtle Mech. In "The Invasion," he argues with Leo and must take charge as leader when Leo is separated from the team. He tries to tell April how he really feels about her until she stops him. At the end of "A Foot Too Big," he tells April he will leave her alone but changes his mind when she kisses him. In "Race with the Demon," his rivalry with Casey is put to an end when they work together to stop the Demon Racer. In "The Eyes of Chimera," he, Raph, Mikey and Casey are taken by Chimera to her nest. In "Vision Quest" he encounters a spirit version of Tiger Claw. In "Return to New York," he fights against Mini Shredder. In "Serpent Hunt," he uses his u-specs to find Karai but she is captured by Rahzar and Fishface and later she is taken by Anton Zeck.
- Hamato Yoshi / Splinter (voiced by Hoon Lee) - Hamato Yoshi was the son and heir of the leader of the Hamato Clan, whose rivalry with the Foot Clan came to an end when he was a child. It was this victory that brought into his family Oroku Saki (Shredder), the child of the Foot Clan's leader, who Yoshi welcomed into his clan as a brother, maintaining an intense but healthy competition with him in their ninja training. As they grew older, their brotherhood was tested (and failed) when both they fell in love with the same woman, Tang Shen, who ultimately chose Yoshi over Saki. As a result, ultimately because of Saki's own jealousy and hatred, their brotherhood ended bitterly, and Yoshi and Shen married and had a daughter named Miwa. Unfortunately, when Shredder learned of his Foot Clan heritage, he attacked Yoshi in the Hamato Clan monastery, seeking to avenge his clan's extinction. During their struggle, a blow meant for Yoshi took the life of Shen, and Shredder, blaming Yoshi for his own error, burned down the monastery and left Yoshi for dead. In disgrace at the loss of both his wife and child, Yoshi left Japan to start a new life in America as "Splinter". After moving to New York City, he had just purchased the Turtles, who were four baby non-mutated red-eared sliders back then, from a pet shop when he was bumped by a strange man in the street. According to Splinter, something felt 'off'" about the man, so he followed him and witnessed a suspicious conversation between two human-disguised Kraangdroids, but the Kraang spotted Splinter and attacked him to keep him quiet. During the fight, the canister the Kraang were carrying broke open and splashed the Turtles and Splinter with mutagen. As the result of stepping on a brown rat while entering the ally, Splinter mutated into a humanoid mutant brown rat. Realizing he could no longer live a normal life on the surface, he retreated to the sewers where he raised his pets as his sons for fifteen years and taught them the ancient Japanese fighting art of ninjutsu. He is very protective of his sons and can sometimes be overprotective. Being a master of ninjutsu, he is capable of defeating a powerful opponent like Leatherhead in "It Came From the Depths." However, given part of his DNA is that of a rat, he proves susceptible to the mind manipulations of the rodent-controlling Rat King, who forces him to battle his own sons in "I, Monster." It takes Leo reminding him of his humanity that enables Splinter to break Rat King's hold over him and defeat his would-be controller. In "Showdown" Pt. 2, Splinter finds out from Shredder that his daughter Miwa is still alive. When he is about to end his former friend, Karai comes to Shredder's rescue. Splinter recognizes her as his daughter and immediately withdraws from the fight and retreats back to the lair. Splinter only hints at learning more from Shredder to his sons, who had just saved New York from the Kraang invasion, rather than make their victory feel hollow. Eventually in "Follow The Leader," Splinter chooses to tell Leo the truth first. In "Of Rats and Men," Splinter's rivalry with Rat King in again tests his limits as a human-rodent hybrid. Using Rat King's own handicap (sight only through the eyes of his rodent subjects to compensate for his blindness), Splinter blindfolds himself and does battle with Rat King until he accidentally falls off a cliff to his certain death. Splinter is again brought face to face with both Shredder and Karai in "Wormquake," where he is defeated and abducted by Shredder's new lieutenant, Tiger Claw. Drugged, he tries once more in vain to convince Karai of the truth, and is forced into an unfair battle with Shredder until the Turtles return to rescue him. It is only when he meditates and shakes off the effects of the drugs do the tables turn and a victory is secured over Tiger Claw. In "The Lonely Mutation of Baxter Stockman," Donnie's discovery of retro-mutagen offers Splinter a return to human form, but given the supply is so little, he willingly sacrifices that chance so that his sons can restore April's father to normal. In "The Wrath of Tiger Claw," Karai becomes unsure of who to believe and feigns a defection to the Turtles' side while planning an attack on the lair with Tiger Claw. Splinter shows Karai a completed copy of the photo she carries around with her of her mother (the completed image being of both Yoshi and Shen), and makes her believe him finally. But their reunion is short-lived as Tiger Claw overpowers her and delivers her back to Shredder, who locks her away. In "Vengeance is Mine," Splinter is once more reunited with Karai after the Turtles' successful rescue attempt. However, he makes the mistake of confiding the entire story of how her mother died to Karai, prompting her to return to Shredder's stronghold to exact vengeance. This results in her again being captured and used as bait to lure the Turtles into a vat of mutagen tainted with serpent DNA (a rat's natural predator). In the course of the rescue attempt, Leo tries to free Karai (suspended over the vat), but Shredder's swipe of his gauntlet meant for Leo cuts the chain instead. Both Shredder and Splinter watch in horror as Karai is mutated into a serpent creature with snakes for hands. Again, Shredder blames his own mistake on Splinter, and Splinter responses with an angry look as if he's also blaming Shredder for his daughter's mutation and barely manages to get through to his daughter before she escapes the fire that her struggle starts in the lab. Leo tries to apologize to Splinter for allowing Karai to escape the lair, but Splinter is too overcome with grief to acknowledge it. In "Into Dimension X," Splinter is seen meditating for days. Leo believes he is "healing his spirit". In "The Invasion," Splinter discovers that April brought her friend Irma to the lair, shocking him that April brought a stranger. Irma then revealed who she really is, shocking everyone. When the Kraang broke in the lair, Splinter bids the Turtles (minus Raph) and April time to escape, while he holds off the Kraang. After defeating (and possibly killing) Kraang Subprime, he witnesses the lair destroyed and leaves to find his sons. When he discovers the Kraang again, Leatherhead comes to his aid and agrees to help him find the Turtles. Later, Splinter fights Shredder and witnesses him seemingly kill Leatherhead. Thinking he is dead, Splinter broke free and continues his fight with Shredder for "killing" his partner. Splinter and Shredder's fight continues through the sewers even when the Turtles arrive. Splinter is then dumped into a sewage disposal similar to where Mikey trapped the Squirrelanoids. Later on, Karai saves him from drowning and places him on dry land. In "Spirit Quest," Splinter appears to the Turtles in a vision stating that he is still alive and has them go on a spirit quest to overcome their issues. In "Return to New York", the Turtles, April and Casey discover Splinter (after April sensing that he was nearby) without his robe, having suffered amnesia from his injuries and a wild rat behavior. He attacks the Turtles and the humans, but he gets captured by the Foot and brought to Shredder. The Shredder then has Stockman-Fly lock up Splinter in a containment unit and to have his memories restored. Stockman-Fly then taunted him with a piece of Swiss cheese before melting it with his corrosive stomach acid and slurping it all up. Later, the Turtles fight Stockman-Fly, who unleashes the Shredder Mutants. When April and Casey try to help Splinter bring back his memories, it becomes a success when April uses her psychic powers to help him. With his memories restored, Splinter eliminates the Shredder Mutants as the heroes quickly escape. They temporarily stay at Antonio's abandoned restaurant. In "Serpent Hunt," he feels left out without his daughter.
- April O'Neil (voiced by Mae Whitman) - The 16 year-old daughter of Dr. Kirby O'Neil, and the love interest of Donatello who befriends the Turtles after the Kraang kidnap her and her father. After the Kraang get away with her father, April's aunt takes her in and the Turtles promise to help her find her father and take down the Kraang. In "Monkey Brains," Splinter learns April has a special spiritual sensitivity and offers to train her to be a kunoichi, which she accepts. As the series progresses, her training starts to pay off. In "TCRI," it is revealed that her father's abduction had nothing to do with his area of expertise but because of the Kraang's unknown plans for April. In "Baxter's Gambit," April learns about Splinter's family and compliments his daughter saying she's beautiful, he shows her the weapon that he was going to give to her, a Japanese war fan, Splinter decides to give it to April. In "Karai's Vendetta," April fights Karai and narrowly beats the better kunoichi. Afterwards, April is forced to stay in the sewers with the Turtles now that the Foot Clan and the Kraang are after her. In "Showdown" Pt. 1, the Kraang mind-controls Kirby to hand April over to Karai so that she can be given to the Kraang. In "Showdown" Pt. 2, April awakens in the Technodrome in the presence of Kraang Prime, who states that her mental energy is what is needed to transform Earth so that the Kraang can live on it. Kraang Prime then begins to siphon the mental energy from April, but she is successfully rescued by the Turtles. In "The Mutation Situation," April's friendship with the Turtles is strained after she learns that one of their attacks on the Kraang was responsible for transforming Kirby. In "Mutagen Man Unleashed," April decides to resume her normal teenage life without remembering the Turtles and befriends Casey Jones upon becoming his tutor. She ends up stalked by Mutagen Man who has developed a crush on her. When the Turtles are fighting Mutagen Man, April works to keep Casey from seeing them. In "Target: April O'Neil," April tries a lot harder to restart her normal life, convincing herself that she doesn't need mutants and ninjas like her father, the Turtles or the Foot Clan and aliens like the Kraang in it anymore, but she realizes that she may have put her human friends such as Casey, in jeopardy when Karai tries to hunt her down again, only to be held back by the Kraang through the new Foot Bot, Chrome Dome. April's friendship with the Turtles is rekindled after they rescue her from both Foot Soldiers. In "The Kraang Conspiracy," the Kraang are shown to have made clones of April, including a "derp" one. When Raph is attacked by the Kraang while trying to save the real April from the DNA extraction machine, she suddenly releases a psychic blast. Afterwards, Donnie studies April's DNA and finds traces of Dimension X alien DNA in it, predicting that she is a half-human, half-Kraang mutant. The news of this leaves April shocked. In "Fungus Humungous," It is revealed that April's worst fear is bats and the loss of her father. In "The Lonely Mutation of Baxter Stockman," Stockman-Fly captures April in a plot to merge with her in mutagen and become one. During a fight between Leo, Donnie, Casey, and Stockman-Fly, the rope holding her breaks and she falls into the mutagen despite Donnie's attempts to catch her. However, it is revealed that April's body is immune to the mutagen's effects due to her alien DNA. In "The Invasion," April is horrified to learn that her friend Irma is a disguised Kraangdroid. She also stops Donnie from sharing his true feelings to her, knowing that it might cause problems. Later, she witnesses her father mutating again, horrifying her. At the end, she mentions her family owns a summer home upstate. Her summer home is then the Turtles, April, and Casey's new base. In "A Foot Too Big," Donnie tells April that he will stop following her but changes his mind when she kisses him. In "Eyes of the Chimera," April briefly sees what the Chimera is through a side effect of the neuro-transmitter going on the fritz. Because of this, it renders April blind to everything else. This lasts until the Chimera is defeated. In "Return to New York," she restores Splinter's mind with her Kraang powers. In "The Pig and the Rhino," she and Donnie are captured by Bebop and taken to Coney Island, where she, Donnie and Casey fight him in the ghost house before he can get to Karai.
- Casey Jones (voiced by Josh Peck) - The 17-year-old son of a former NHL player at April's school who April is hired to tutor for an extra credit assignment. When they first meet, he shows April his courtesy and the two quickly become friends, much to Donnie's jealousy. He shows admirable fighting skills, especially when he helps April fight Mutagen Man and an entire Foot Bot squad in "Mutagen Man Unleashed" and "Target: April O'Neil". Casey also remindes April of Donnie by repeating his quotes and stating that pizza is his favorite food. In "The Good, the Bad, and the Casey Jones," Casey takes up a crime-fighting hobby following these recent incidents, arming himself with hockey sticks, baseball bats, and a stunner in one of his hockey gloves. He ends up being introduced by April to the Turtles and Splinter when he follows Raph into their home, and helps the Turtles when two Foot Bots invade their lair. In "Of Rats and Men," Casey seems to be extremely terrified of rats. In "The Invasion," Casey drives Kirby's old hipster vehicle, the Party Wagon, for him to get his family and friends out of the city. However, his unable to find his family and predicts that they were mutated as he, April, and the Turtles flee the city. In "Race with the Demon," his rivalry with Donnie is put to an end when they work together to stop Speed Demon. In "The Pig and the Rhino," he and Raph are captured by Rocksteady and taken to Coney Island, where they, Donnie and April are freed by Leo and sent into a ghost house stop Bebop from getting to Karai before they do. In "Casey Jones vs. The Underworld," Casey tries stop the Purple Dragons from robbing a bank, but he is defeated by their new leader, Hun. Later, he follows Shredder, Tiger Claw and Fishface to the meeting with Don Vizioso and is almost caught. After attacking Rahzar and Fishface at the docks, they are about to kill him, but Raph interferes and knocks out both of them. Casey eavesdroppes the conversation between the Shredder and Hun then he attacks the Shredder in Auman Chemicals factory. The Turtles arrive and Casey takes on Hun. He manages to defeat Hun and throws the chemical into the mixing vat. In "Meet Mondo Gecko," he and Mikey encounter Mondo, who attempts to help them fight the Purple Dragons, but this gets Casey captured and being forced to participate in a deadly skate race organized by Fishface.
- Hamato Miwa / Karai (voiced by Kelly Hu) - Hamato Miwa was the daughter of Hamato Yoshi (Splinter) who, as a baby, was taken away from Splinter by Oroku Saki (Shredder) after a fight between the two men that burned down the Hamato Clan monastery and killed her mother, Tang Shen, and raised as a member of the Foot Clan and expert kunoichi under the name Karai. She is Leonardo's love interest and sweetheart. She first appears in "New Girl in Town" during a duel with Leo, while the other Turtles are out looking for Snakeweed. Karai tries to encourage Leo to break the rules for a change, daring him to help her steal a sword once owned by swordsman Miyamoto Musashi. When Leo's life is threatened by Snakeweed and he asks for her help, Karai throws a knife toward him, (which helps him break free), which Leo interprets as an act of friendship but which Raph considers malicious. In "The Alien Agenda," she attacks the Turtles at the Kraang's World Wide Genome Project and pushes a button which causes all the animal and plant DNA to be dumped into the mutagen resulting in the creation of a composite beast, Justin. Karai escapes with the Kraang robot body and presents it to Shredder. As Baxter Stockman gets to work studying the technology, Shredder assigns Karai to learn more about the Kraang so that he can use whatever information is gathered about them in his war against the Turtles. In "Enemy Of My Enemy," Karai becomes aware of what kind of threat the Kraang represents after seeing their new scout ship and offers the Turtles help fighting them, since Shredder is focusing on plans for a weapons deal. At first, the Turtles insist not to except the offer, but after talking it over with Splinter and seeing Karai lure the ship away from them, they decide to agree, if she gets a rocket launcher from Shredder's weaponry shipment for them to shoot the Kraang and their ship down. However, unbeknownst to Karai, the Turtles secretly plot to kill Shredder, but she foils it and fights Leo as Shredder and the Kraang go after the other three Turtles. In a final attempt to stop the Kraang, Leo fires the rocket launcher at their scout ship, blasting out of the sky and into the harbor and leaving Karai to rescue Shredder (who almost goes down with it) and carry him back to shore, where he reveals to her that he has captured one of the Kraang pilots. In "Karai's Vendetta," Shredder interrogates the captured Kraang (even when Karai informs them on how they work their exo-skeletons) on why they have been hunting the Turtles and learns that they are protecting April O'Neil. He then sends Karai to capture April in order to draw the Turtles to him. After a chase throughout the city, April manages to trick Karai into letting her guard down by mentioning that her mother is dead (which is the same with Karai) and throws Karai down the subway stairs. In "Showdown" Pt. 2, Karai comes to Shredder's aid as Splinter is about to deliver the finishing blow. He immediately recognizes her as his long-lost daughter, but Karai reveals she believes Splinter killed her mother Tang Shen, a lie fed to her by Shredder as a child. Upon learning this, Splinter evades Karai's attacks and retreats in sadness. In "Follow the Leader," Karai is seen training with the Foot Bots until Shredder arrives and tells her not to do any actions towards the Turtles while he is in Japan dealing with an urgent matter. She goes against Shredder's orders and decides to test the Foot Bots on the Turtles. When Leo gets captured, Karai has the Foot Bots attack him as part of their training at the Bradford Dojo, where they manage to defeat them. Upon the other Turtles arriving, Karai has the Foot Bots restrain them so that she can draw Splinter to her. When the Turtles make a tactical retreat, she orders the Foot Bots to pursue them and engages Leo to a sword fight where Leo tries to convince her that Splinter did not take the life of her mother. In "Target: April O'Neil," Karai leads the Foot Bots in an attack on April at one of her tutoring sessions with Casey Jones at an ice rink, which fails when Donnie rescues her and the new Foot Bot leader, Chrome Dome, arrives (followed by the other three Turtles) and intervenes with both sides intentions for the Kraang. In "Wormquake," Leo tells her that Splinter is her real father, but she does not believe him. After the defeat of Tiger Claw, Raph then wonders where Karai is now while April still cannot believe that she is Splinter's genetic daughter. Splinter states that one day Karai may indeed accept the truth, but that is her decision to make and hers alone. Unbeknownst to all of them, Karai is secretly hiding behind a billboard not too far away from them, listening to everything that they say. Judging by her several facial expressions, not only does she find herself in a difficult dilemma, but finally seems to start questioning herself. In "The Wrath of Tiger Claw," she begins to doubt that Shredder is her real father as she looks at a picture of her mother and hears the words Leo said to her from "Wormquake." When Shredder arrives, he asks her what is troubling her. Karai asks him to tell her more about the truth about her mother and him, but Shredder claims she already knows the "truth", but his words are interrupted when Tiger Claw returns and Shredder sends him and Karai to go after the Turtles again. Together, they break into Mr. Murakami's restaurant to ask him where the Turtles are. When Karai catches April, she doesn't insist to fight her and wants to tell something about her. When Leo and Donnie see Karai with April, they both head to the girls. Karai tells Leo that she believes him about telling her that Splinter is her real father. Leo takes her to their lair to see Splinter, but Donnie knows Raph isn't going to believe this. As soon as they arrive (with Casey knocked out after Tiger Claw threw him off a building), a surprised Raph harshly states his displeasure of having a relative employed by the Foot Clan in the lair. She tells him that she didn't know that Shredder lied to her, but Raph still remains unconvinced and threatens her with his sai. While Leo and Raph continue arguing, Karai secretly uses a tracking device to have Tiger Claw locate where the Turtles are. She then encounters Splinter, who shows her to the training room and reveals a picture of himself as a human with Tang Shen and with Karai as a baby. Karai, feeling guilty, apologizes to him and the Turtles, but doesn't plan to stay because she signaled Tiger Claw, getting Raph to angrily claim that he was right about her. Before she leaves, Splinter tells her that she is who she chooses to be, not what others make her. At a meat factory called "Patty Man's" (which was Mikey's idea), Tiger Claw fights the Turtles and gives Karai the opportunity to finish off Leo, but she turns on him. Tiger Claw then kidnaps her to take her to Shredder's lair with Leo watching in horror, but Raph still doesn't insist on helping her and Mikey is badly injured. Upon returning to Shredder's lair with Karai, Tiger Claw tells Shredder that she has betrayed him and was fighting alongside the turtles. When Karai angrily asks Shredder if Splinter is her father, Shredder says yes, which makes Karai shocked that she was lied to by Shredder her whole life. Shredder orders Tiger Claw to take her away. Karai is locked in a dungeon cell as Tiger Claw and Shredder leave, causing her to scream in horror. In "The Legend of the Kuro Kabuto," she tries to escape from her cell while covering it up in front of a visiting Shredder. In "Vengeance is Mine," the Turtles succeed in rescuing Karai from Shredder. Reunited with her father after returning with them to their lair, Karai learns from Splinter about the rivalries between the Hamato Clan and the Foot Clan. As a result, she goes after Shredder alone for revenge, but he manages to overwhelm her (because Shredder had trained Karai she held no surprises for him). He then plans to use her as bait for the Turtles so that they can fall into a trap and be thrown into Stockman-Fly's mutagen vat and mutate into snakes after Stockman-Fly pours albino horned viper DNA into it. During the Turtles and Splinter's mission, Leo tries to rescue Karai until Shredder interferes and unintentionally breaks the chain supporting Karai's. Because of this, Karai falls into the mutagen and mutates into a gigantic mutant albino horned viper with a pair of extra heads for hands (referred to in the toyline as Serpent Karai and is similar to Scale Tail from the 1987 toyline) and metal features on her shoulders, torso, and parts of her tail. This causes the shock of both Splinter and Shredder (as well as the two blaming each other for Karai's mutation). Karai's mutated form ends up causing a fire in Stockman-Fly's lab, alerting both sides to retreat. In a twist ending, it is shown that Karai can change at will between her human and mutant form yet still has some snake traits in her eyes, fangs and tongue. There is no doubt that the extra chemical Stockman-Fly accidentally adds into the mutagen allows Karai to this. In "The Invasion," she is spotted by Raph, who is searching for her just as the Kraang begin their invasion. She later rescues Splinter from drowning and places him on dry land, giving him a nudge on the shoulder before leaving. In "Serpent Hunt," she is being searched by the Turtles and hunted by Anton Zeck and Ivan Steranko. The Turtles re pointed in the right direction in their search when they discover snake scales on the ground, which Mikey believes they are potato chips and starts eating them until Donnie reveals what they really are. However, Karai escapes from them during the fight with Zeck and Steranko. Following her into a warehouse, the Turtles are attacked by Kraangdroids, but Karai comes to their aid and destroys the robots. She then reveals to them that she can transform between her human and mutant form. While they convince her to come back with them, they are attacked by Rahzar and Fishface, who are sent by Shredder to search for her. As they take the unconscious Karai with them, they fill the warehouse with poison, but the Turtles manage to escape, and Zeck steals Fishface's motorcycle, with Karai on it. As he and Steranko make a deal with Shredder that they will give him Karai in exchange to get out of the city alive at the docks, the Turtles fight the Foot as Leo frees Karai. While telling her to leave to safety, Karai points out to east in the city and saying "Comet" before following their direction. In "The Pig and the Rhino," Leo and Mikey find her at a local amusement park called Coney Comet as Rocksteady and Bebop arrive. After Rocksteady and Bebop get away, Leo tries to use the retro-mutagen spray on Karai, but it doesn't work due to her special mutation. As her intelligence fades, Karai says goodbye to the Turtles before diving into the water. While trying to prey on a nearby rat, Karai is trapped by Rocksteady and Bebop and presented to Shredder, who vows to Karai to cure her of her mutated state. In "Casey Jones vs. The Underworld," she is seen in a cage and looks like she has completely lost her mind. In "The Deadly Venom," Stockman-Fly successfully restores her human form and infectes her brain with a mind-controlling worm. Shredder then orders her to attack Rocksteady, who she defeats easily and then hunt and destroy the Turtles and their allies. During this time, Karai gets better control of her transformations where can also switch between human and mutant horned viper forms (like having a human body with snake-headed arms) as well as snake-controlling abilities. She first sends these snakes to bite April in her bed and get the drop on Casey, who gives her a good fight. By using both her ninja skills and her new control over her mutant powers, she over-poweres him and give him a poisonous kiss. When Mikey and Raph come to save him, Karai's snakes come out of Casey's clothes and bite them. She then uses all four of them as bait for Leo and Donnie and places some of her venom in the water they swim in. With Leo poisoned, she quickly gets the upper hand, but by using a healing technique Splinter recently teaches him, Leo beats her venom and defeats her. When he turns his back for a minute, she was gone.
- Kirby O'Neil (voiced by Keith Silverstein) - The psychologist father of April O'Neil, who meets the Turtles when he and April are captured by the Kraang. Although April is rescued by the Turtles, the Kraang take off with Kirby. In "The Gauntlet," the Turtles learn from Kirby that the Kraang have been abducting scientists so that they can help modify the unstable mutagen. The Turtles are unable to rescue Kirby as he is recaptured, buying the Turtles time to escape. In "TCRI," it is revealed that since Kirby is a psychologist, his abduction has nothing to do with the mutagen....the Kraang's real target is April. In "Operation: Breakout," Kirby is officially rescued by the Turtles and reunited with April. However, he has fallen under the Kraang's control. In "Showdown" Pt. 1, the Kraang control Kirby into handing April over to Karai and the Foot Ninjas. In "Showdown" Pt. 2, the Turtles discover the mind-control device on the back of Kirby's neck and free him. In "The Mutation Situation," Kirby is having recurring nightmares about the Kraang. Kirby ends up helping the Turtles track down a Kraang stealth ship carrying a shipment of mutagen. When a mutagen canister falls towards April, Kirby protects his daughter from the canister and falls off the roof, taking the mutagen himself. As the result of falling past a flock of vampire bats, Kirby mutates into a humanoid mutant vampire bat with a large head, wings on its back, ears shaped like bat wings, a small right arm, and the retaining of his red hair and beard that Mikey, against Donnie's wishes, dubs "Kirby-Bat" (which is what the action figure of his mutated form is referred to and was confirmed to be a new mutant by Brandon Auman) and "Wingnut" (a classic character although the Wingnut reference was just a joke). Kirby-Bat chases after April and flies off with her. When April awakens on another roof, Kirby-Bat arrives and regurgitates what he would consider food, such as rats and garbage. With Mikey dressed up as a butterfly which he names "Tur-fly-tle" as part of a plan to get Kirby-Bat, the Turtles use Mikey as bait to trap him in a warehouse by drawing Kirby-Bat towards them. The Turtles struggle to get through to Kirby-Bat's side as they work to trap him in the warehouse. Once inside the warehouse, the Turtles trap him in a cage as April catches up to them. As Donnie vows to find a way to cure Kirby-Bat, he breaks free and ends up flying off. The mutation of Kirby had temporarily put a strain in April's friendship with the Turtles. In "Fungus Humungous," he appears as hallucination as one of April's fears, which are bats. In "Metalhead Rewired," Kirby-Bat is among the mutants captured by Kraang in order for them to control them. He is first discovered by the Turtles in his cell. Then he, Cockroach Terminator, a Parasitic Wasp and a Squirrelanoid discover that Metalhead has opened their cells. He is then attacked by two Kraang, but Donnie kills the two aliens with his bo staff. He then tells Kirby-Bat to head to the portal for April. With help from Metalhead, the Turtles free the captive mutants and they escape through the portal, leaving Kirby-Bat's location a mystery. In "The Lonely Mutation of Baxter Stockman," Kirby-Bat assists the Turtles into fighting Stockman-Fly over retro-mutagen. When the retro-mutagen canister hits a street light, April steers Kirby-Bat under one of the falling drops which is enough to mutate him back into Kirby O'Neil. In "The Wrath of Tiger Claw," Kirby is seen trying to call his daughter, but is unable to and he says that his daughter always answers the phone. In "The Invasion," he feels sad about the Kraang's invasion on humanity and reveals his old Party Wagon to his daughter and her friends. Unfortunately for Kirby, Kraang Prime peers around the corner from behind and sprays him with the perfected mutagen before he can leave with them. This ends up mutating him into a half-Kraang monstrosity much to April's horror. He is mentioned in "Buried Secrets" when Mom-Thing (disguise as April's mother) asks where he was. Casey is about to tells her that he got mutated into a half-Kraang creature, but Raph stops him. As a cover-up, Leo says that Casey was kidding and lies by saying that Kirby is on a safari in Puerto Rico. In "Return to New York", it is revealed that he is brought to Dimension X while in service to the Kraang, collecting bang rocks. In "Battle for New York" Pt. 1, he is returned to normal by the Turtles and teleported back to Earth. When April sees him, she becomes so excited to see her dad and they give each other a hug.
- Timothy / Pulverizer / Mutagen Man (voiced by Roger Craig Smith) - Timothy was an ineffective teenage ice cream truck vendor who eyewitnesses the Turtle's first battle with Baxter Stockman from his apartment window and, ever since then, dedicates himself with fighting crime as a costumed vigilante calling himself the Pulverizer and models his appearance after the Turtles. He first appears in "The Pulverizer," where the Turtles rescue him from a bungled attempt to stop the Purple Dragons from looting a warehouse. Pulverizer winds up back at the Turtles' lair after he accidentally gets stuck to the Shellraiser. Taking pity on the would-be hero, Donnie attempts to train Pulverizer in basic self-defense, but Pulverizer shows little capacity to learn. In a failed attempt to stop the Kraang from fleeing with their power cell, Pulverizer winds up in need of help, and Donnie chooses to save him instead of getting the power cell back. Pulverizer vows to train on his own in order to be better the next time he meets the Turtles. In "The Pulverizer Returns," Pulverizer is recruited into the Foot Clan (mainly to serve as a "cannon fodder") and agrees to gather info on Shredder's plans for the Turtles, only to later volunteer to be the test subject for a supply of stolen mutagen. During the Turtles' rescue attempt, he attempts to activate the mutagen machine, but is stopped multiple times by Donnie. However, he is successful on one attempt causing the mutation to occur. As the result of not coming in contact with any living thing, Pulverizer mutates into a 6 ft. mutant blob of mutagen with floating organs and a disintegrating touch that Mikey dubs "Mutagen Man" (becoming this series' interpretation of Mutagen Man). Mutagen Man is rescued from the explosion his mutation causes by the Turtles, who work together to place him in an empty mutagen container, and Donnie vows to find a way to restore him back to normal. In "The Mutation Situation," Donnie and Metalhead are seen testing his organs. Again, he is seen briefly in "Invasion of the Squirrelanoids." In "Mutagen Man Unleashed," Donnie develops a voice box so that Mutagen Man can speak easily. Mutagen Man drinks some of the mutagen samples and gains the ability to form new arms and legs outside of his container. In this form, Mutagen Man goes after April upon developing a crush on her. When Mutagen Man finds April, he ends up attacking Casey Jones who tries to fight back. April helps Casey to fight Mutagen Man as they escape on Casey's bicycle. As April and Casey get away, Mutagen Man is confronted by the Turtles where he is officially named by Michelangelo. Mutagen Man then starts to power down upon running out of mutagen. During the ride back to the lair, Mutagen Man drinks from a mutagen container and escapes from the Shellraiser and goes after April again. The Turtles manage to catch up to Mutagen Man near April's apartment. Using camouflage and misdirection that involves mutagen, the Turtles fool Mutagen Man where they end up freezing him with a retro-mutagen prototype that had similar affects of liquid nitrogen. Mutagen Man's frozen body is taken back to the lair as Donnie vows to continue finding a cure for him. He is seen numerous times frozen in Donnie's lab in some episodes. In "The Invasion," Mutagen Man's frozen body is seen when the Kraang storm the lair. While packing his stuff, Donnie says good-bye to Timothy, rather than taking him with them. He tells him that they'll be back, but if they don't, he should defrost in about 70 years or so and hopes the world will be a better place by then.
- Jack J. Kurtzman (voiced by Robert Forster) - A private investigator and journalist investigating the disappearance of Kirby O'Neil and other missing scientists, leading him to discovering the Kraang and investigating them on his own. Displaying a book full of notes, he insists that the Kraang presence on Earth is "ancient" and actually goes back thousands of years. He first appears in "The Kraang Conspiracy," where he is taking pictures of the Turtles while they and April are out on a mission. The Turtles follow Kurtzman to his apartment and he introduces himself to them, explaining that he has been investigating the Kraang. He shows them a picture of April as a baby and tells her and the Turtles that the Kraang have been attempting to terraform the Earth for thousands of years, but needed a "specific chain of human DNA", so they kidnapped April's mother before April was born and used her in their experiments. He explains that with April's DNA, the Kraang could perfect the mutagen in this dimension. Eventually, the Kraang manage to find them. Kurtzman, the Turtles and April retreat, but the Kraang follow them so they get away in the Shellraiser. Afterwards, Kurtzman tells them that they need to infiltrate TCRI in order to erase all of April's DNA codes. The Turtles succeed after the fight with the Kraang and the April clones and get away with in Kurtzman's van. Kurtzman states that he'll be in touch. In "Wormquake," April and Donnie meet him about the Kraathatrogons. Lucky for them, Kurtzman shows photos of the Kraathatrogons and calls the Kraang's scheme the "Manhattan Project". He reveals that the Kraathatrogons are only children while the adults are huge and some are hundreds of feet long and shows that the Kraang brought them from Dimension X to take them to their machines in order to collect their mutagen, which is kind of like milking a giant cow, much to the two's disgust (mostly April's). Kurtzman also explains that there isn't a clue to stop them, but he knows that the Kraang ride on them and to control the worms is by pulling the antennas like the reins on a horse (which April finds gross). In "Battle for New York" Pt. 1, it is revealed Kurtzman escaped from being mutated and has become the Mighty Mutanimals' benefactor. When the Turtles meet him again, Kurtzman reveals that the Kraang are making a mutagen missile that will be launched into space and mutate people all over the world. When the Mutanimals and Turtles argue (except for Mikey and Leatherhead), the Kraang attack and Kurtzman is injured. When they all get to safety, Kurtzman hands Leo a hard drive from his computer that will deal with the missile before he passes out from his injury. After the Kraang are defeated and the humans are restored to normal and returned to Earth, Casey and April walk with the recovered Kurtzman.
- Mighty Mutanimals - A team of mutant animals that debut in "Battle for New York" Pt. 1. They were brought together by Jack J. Kurtzman to fight the Kraang.
- Spike / Slash (voiced by Corey Feldman) - Spike was a box turtle that was raised as a pet turtle by Raph when he was flushed down the bathroom toilet of his original owner's home. Raph has a soft spot for him, and often talks to him about his feelings in private. This is important for Raph because he needs Spike as a sounding board for his inner thoughts and feelings. He can't reveal his feelings to his brothers so he shares them with Spike, who can't speak, but is an excellent listener. His brothers tease him about this sometimes. Spike's favorite food is lettuce leaves, which he is often seen eating, and rides around more often on Raph's shoulder. In "Slash and Destroy," Spike mutates into a large humanoid mutant box turtle with a spiked shell, a tough horned head, extending bony nails used as makeshift weapons, vocal mimicry, amazing agility and superhuman strength by drinking some mutagen that spills in Raph's room after he confiscates it following an incident that nearly kills him. Upon understanding about what Raph has to go through, Spike renames himself "Slash", obtains a mace for a weapon, puts on a black mask, and states to Raph that they need to lose some dead weight when they head out to find a mutagen container. During the mission, Slash starts attacking Donnie and Mikey where Raph claims that the mutation has warped Slash's mind. As Slash plans to dispose of Mikey and Donnie, Raph states that he didn't want this happening to his brothers. However, Slash states that there is no turning back now, so Raph ends up working to prevent him from disposing of Donnie or Mikey, only to learn from him that he has spent years watching Raph train and knows what he can do. Raph comments that he doesn't know all of his moves. Their fight wrecks the area where Leo is having tea time with a girl who was using the "mutagen" to pass as tea. Leo ends up showing up to help Raph only to knock him down. During the fight, Raph hits a vulnerable part on Slash's arm and falls off the building. When Raph looks over the building, Slash's body is gone as the Turtles suspect that Slash had gotten away. In "Metalhead Rewired," Slash is among the mutants captured by Kraang in order for them to control them. He is first discovered in his cell, while yelling at the Kraang. He is then released by Metalhead as he begins to destroy the Kraang for capturing him. Slash does help Raph defeat some Kraangdroids and then escapes with Pete and Spider Bytez. With help from Metalhead, the Turtles free the captive mutants and they escape through the portal. In "Newtralized," Slash gets captured by the Kraang again but this time, he is freed by Newtralizer and the two of them start working together to stop the Kraang's plots. Of course Slash gets concerned over Newtralizer's motives involving the humans getting in the crossfire. During the fight at the docks, he goes against Newtralizer's plot to annihilate the Kraang and the city at the same time, causing Raph to help him out. After Newtralizer and the Kraang Walker it is piloting are defeated, Raph states that there is a room back in the Turtles' lair for him, but Slash declines stating that he is walking his own path and leaves Raph on equal terms. In "The Invasion," he appears as a photo of his normal form. Raph is hoping that Slash has escaped the invasion. In "Battle for New York," Slash has formed the Mighty Mutanimals, and his lips are light green than before. Leo doubts him for what he did last time to them, and thinking he's using his team as bait. During the attack on TCRI his team is overwhelmed and he has to surrender. When the Mighty Mutanimals manage to break free, Slash destroys Mrs. Campbell with his mace. In "Clash of the Mutanimals," he and the other Mutanimals attack Tiger Claw and the Fulchi twins, but he and Rockwell are knocked out and taken to Stockman-Fly, who uses them as the test subjects for his mind-controlling serum. However, Slash and Rockwell manage to get away (though it looks like they were allowed to escape) and run into the Turtles and the rest of their team. Once arriving at the lair, Slash attacks Splinter, and after a brief fight, he and Rockwell leave with an unconscious Raph. When their friends arrive at the Shredder's lair, Raph, Slash and Rockwell are released from the mind-control. The Turtles and Mutanimals attempt to take down Shredder but are forced to retreat.
- Leatherhead (voiced by Peter Lurie) - An American alligator that was originally owned by a young boy until his parents found out and flushed him down their bathroom toilet into the sewer. The Kraang found him, took him back to Dimension X, and experimented on him, mutating him into an 8 ft. humanoid mutant alligator with a tough hide, uncontrollable force in his spirit, keen senses and superhuman strength. But since the Kraang were unable to break his spirit, he easily escaped from them, stole the cell that powers their portal between Dimension X and Earth, and retreated back to the sewers, vowing to keep them from getting it back so that they can start their invasion. He first appears in "It Came From The Depths," where the Kraang locate and attack him, demanding the return of the power cell. The Turtles witness this event and Mikey urges his brothers to help intervene. Soon after the Turtles protect Leatherhead, restore his health, and learn of his origin, they help him keep the power cell away from the Kraang. In "TCRI," Leatherhead tells the Turtles where the Kraang's base is by drawing the shape of the TCRI building. He helps them by attacking the Kraang while they make their way to the top of TCRI and dragging Traag back into the portal to Dimension X. In the "Mazes & Mutants," the Turtles encounter a fire-breathing dragon who resembles Leatherhead, but bigger. Mikey, believing it to be his long gone friend, refuses to fight because of their friendship, only to find out that it isn't the real Leatherhead. The illusion is seen again when Sir Malachi leaves. In "Into Dimension X," the real Leatherhead is seen with more scars and gray skin after he was stranded in Dimension X for many decades (this was due to the time difference between Earth and Dimension X). He sends a message to the Turtles in a Kraang Communication Orb to tell them that the Kraang have perfected the mutagen, but is recaptured by the Kraang. Later, after the Turtles receive the message (much to Mikey's joy that his best friend is still alive), they quickly head into a Kraang portal (which Donnie opens) and into Dimension X. When they find and free Leatherhead, they are surprised to discover that he's become an old mutant. Together, all five of them fight the Kraang and close all the portals. During the fight, Leatherhead helps Leo just by simply grabbing his face to fling him to fight off one of the Kraang's robots. Leatherhead tells the Turtles to go through without him, while keeping the Kraang busy. However, Mikey would not leave his friend behind and pushes him back to the portal. After they make it back to Earth, he and the Turtles give each other a high three and get ready for the next invasion that the Kraang are planning. In "The Invasion," Leatherhead helps Splinter fight off the Kraang. When Splinter thanks him and asks him if he'll help him find his sons, Leatherhead agrees as they both head to the surface. Later, just as the Shredder is about to kill a trapped Splinter, Leatherhead reappears and attacks him, but is unable to crush him due to his old age. He rushes to free Splinter, but Shredder takes him down and seemingly kills him, but it is not confirmed as his body falls through the icy water. Splinter becomes upset and furious at Shredder for "killing" his friend as he breaks free and attacks Shredder, sending them both in the sewers. But after they fell in the sewers, Leatherhead's body is never found. In "Battle for New York," it is revealed that Leatherhead survived and has become a member of the Mighty Mutanimals as Slash's second-in-command. Mikey becomes so happy to see his friend again. After the mutagen missile is stopped, he rejoices with Mikey as they all head to TCRI. During the attack on TCRI he and the rest of the team were captured by the Kraang. But later they've managed to escape and reopen the portal to the Dimension X. In "Clash of the Mutanimals," the team is overwhelmed by Tiger Claw, who takes Slash and Rockwell, so Leatherhead and Pete meet with the Turtles and together, they head to Shredder's lair.
- Pete (voiced by A.J. Buckley) - A wood pigeon living in New York that was mutated by the Kraang into humanoid mutant wood pigeon with large sharp talons and strange mutagenic growths all over his body. Pete learned how to talk and befriended Kirby O'Neil, who uses him to send a message to his daughter in "The Gaunlet." Pete has a strange yet large craving for bread and will do anything to get some, telling the Turtles the location of where Kirby is in exchange for it. In "Metalhead Rewired," Pete is among the mutants captured by Kraang in order for them to control them. He is seen shortly with a Squirrelanoid and a Parasitic Wasp, then he makes for the portal with Slash and Spider Bytez. With help from Metalhead, the Turtles free the captive mutants and they escape through the portal back to New York. In "Battle for New York," Pete is the spy of the Mighty Mutanimals and is wearing a small helmet. When Slash throws a loaf of sourdough bread at any Kraang, it causes Pete to react and attack the enemy to get the loaf of bread. Raph still thinks Pete is quite useless.
- Dr. Tyler Rockwell / Monkey Brains (vocal effects provided by Frank Welker in the first appearance, voiced by Tom Kenny in the second appearance) - Tyler Rockwell was a British neurochemist who was Victor Falco's science partner and colleague until he was unknowingly used as a subject in Falco's experiment involving mutagen, a neurochemical, and monkey DNA. As a result, Rockwell mutated into a humanoid mutant monkey that can sense emotion (referred to in the toyline as "Monkey Brains"). He first appears in "Monkey Brains," where Falco reports him missing after Rockwell escapes from his grasp. After the Turtles uncover the truth and defeat Falco, they release Rockwell, who heads to the window. Before he does, he turns back to look at the Turtles as if he's trying to thank them. In "Metalhead Rewired," Rockwell is among the mutants captured by Kraang in order for them to control them. He is first seen being brainwashed in his chamber when the Turtles discover him. After Metalhead sets him free, he, Newtralizer and a Squirrelanoid escape, then Rockwell beats up one of the Kraangdroids before heading to the portal. With help from Metalhead, the Turtles free the captive mutants and they escape through the portal. In "Mazes & Mutants," the Turtles fight the Monkey Goblins used by Sir Malachi, that all resemble Rockwell. The Turtles find the Monkey Goblins to be someone they know. The illusions were seen again when Sir Malachi leaves. In "Battle for New York," the real Dr. Rockwell becomes the brains of the Mighty Mutanimals and is wearing a Kraang helmet wearing high-tech. It is revealed that the Kraang experimented his mind, allowing him to gain psychic powers and retain his human voice again. Donnie becomes jealous of him when he keeps interrupting him of knowing everything. After the mutagen missile is stopped, Donnie and Rockwell finally get along with each other, though Rockwell predicts that warm-blooded animals are a lot smarter than cold-blooded animals. When the Mighty Mutanimals attack TCRI, Rockwell opens the portal to the Dimension X. Later, when they're locked up by the Kraang, he uses his psychic powers to release them. He was about to be killed by Mrs. Campbell, but Slash destroyed her by the throw of his mace and Rockwell managed to reopen the portal.
- Ice Cream Kitty (vocal effects provided by Kevin Eastman) - A stray tabby cat that April finds in an alley and, deciding to find it a home, asks Mikey to raise as his pet. Upon unknowingly eating mutagen that was accidentally poured onto a bowl of Neapolitan ice cream on Donnie's lab table, the cat mutates into a small mutant tabby cat made of a small mountain of Neapolitan ice cream that Mikey dubs "Ice Cream Kitty" and hides in the freezer while trying to keep the others from learning of it. Mikey later used Ice Cream Kitty to help fight The Rat King where Ice Cream Kitty broke Rat King's control over Splinter. Donnie tells Mikey that they will have a talk about the incident that caused Ice Cream Kitty's transformation later. In the episode "Mazes & Mutants," Ice Cream Kitty seems to be friends with Splinter, considering giving him a cheesesicle (a frozen treat, which consists of a slice of Swiss cheese on a popsicle stick). In "Newtralized!," Ice Cream Kitty makes another appearance when she gives Raph an ice pack for Casey's head. In "Pizza Face," she gives Mikey a cheesesicle so he can make pizza. She supposedly attacked one of Pizza Face's minions when Mikey locked him in the freezer, but it's not confirmed as she just freaks it out with a haunting turn. In "The Invasion," she helps Mikey knock out a Kraang with the freezer's door. When the Turtles pack their stuff, Ice Cream Kitty refuses to leave, but finally accepts it as she fits in the cooler between two frozen pizza boxes. In "A Foot Too Big," she meets Bigfoot when she opens the freezer. They both scream when they see each other before Bigfoot throws the fridge out of the cabin. In "Buried Secrets," it is shown that she actually understands Mikey suspecting April's mother as a fake. While listening to him, Mikey sprays some whipped cream on her head and placing a cherry on top. Ice Cream Kitty then senses something and begins to hiss furiously, revealing April's mother with a canister of mutagen and letting Mikey go after her. In "The Croaking," she and Mikey are playing around in the living room while watching Crognard the Barbarian. However, their fun time causes a huge mess, which makes his brothers and Casey yell at him. Ice Cream Kitty then hits Raph for being mean before she is placed back in the freezer. When Mikey decides to leave, he makes a farewell to his beloved pet. In "Vision Quest," Mikey tells her that he's going out to the woods to overcome his issues. "In Return to New York," she becomes happy that she and her family are going back to New York. In "Battle for New York" Pt. 1, she and Mikey are shown making formulas, agreeing about Mikey's idea of combining the plutonium with sodium bicarbonates. When Mikey adds Retro-Mutagen with the plutonium, it makes Donnie shocked and it triggers a slight explosion (though Ice Cream Kitty seemed to enjoy it).
- Bigfoot (voiced by Diedrich Bader) - The legendary cryptid. She first appears in "A Foot Too Big," where she is being hunted by a collector named The Finger. Donnie and Mikey encounter her while doing a "Turtle Hunt" with Raph. When Raph arrives, he helps them in an attempt to fight Bigfoot, Donnie finds a wound on Bigfoot's arm and, thinking that she's hurt, decides to take her back to the barn to get the wound cleaned. Upon getting Bigfoot into the house, April bandages up her arm and gives her a makeover while mentioning about Finger being after her. Bigfoot then gets affectionate with Donnie. While Raph cleans out the bathtub after Bigfoot makes waste in it, Bigfoot shows the other Turtles some forest stealth, but is nearly attacked by Finger along with Donnie and Mikey. After overhearing Leo and Casey making jokes about her, she runs off crying with Donnie and Mikey apologizing after her. Bigfoot falls into Finger's pit trap. Donnie and Mikey attempt to rescue her, but gets captured by Finger as well. While distracting Finger by insulting his shrunken-head mama, the two Turtles free themselves and fight him. Realizing his defeat fighting the Turtles, Finger threatens to kill Bigfoot. Emerging from the trap's netting, the makeover April gave Bigfoot earlier causes Finger to realize that she's a lady who he is unable to harm. As Finger apologizes to his shrunken-head mama for unknowingly trying to hurt a lady, Bigfoot comforts Finger and soon grows affectionate for him. Bigfoot then leaves with Finger in her arms.
- Punk Frogs - A group of humanoid mutant frogs that are the results of mutagen being dumped near their pond during Mikey's fight with Mom-Thing in "Buried Secrets". In "The Croaking," the Frogs are seen robbing camp sites until Mikey meets them at the Frog Fortress in their tree. After capturing April and Casey, the Frogs plot to use their Frog Soldiers to invade the cities in order to get revenge on the humans for destroying their environment. The other Turtles arrive and fight the army until the tree is set fire. After understanding that not all humans are bad after being rescued by April and Casey, the Frogs leave to Louisiana to live with the frogs that reside in the bayou.
- Attila the Frog (voiced by Maurice LaMarche impersonating Marlon Brando) - The leader of the Punk Frogs who is named after Attila the Hun. He first appears in "The Croaking," where, upon meeting Mikey and learning about his brothers at the O'Neil family house, he sends Genghis Frog to "liberate" the Turtles from the humans, stating that the humans are the reason behind the loss of their environment and planning to use the mutagen that Rasputin studies to invade the cities to get revenge on the humans. When the rest of the Turtles arrive, Attila fights against Leo. After being rescued from the fire by April and Casey, Attila sees that not all the humans are evil and promotes Napoleon to general upon seeing the wisdom in him.
- Genghis Frog (voiced by Kevin Michael Richardson) - A member of the Punk Frogs who leads the Frog Soldiers and is named after Genghis Khan. He first appears in "The Croaking," where he leads the Frog Soldiers into "liberating" the Turtles from April and Casey. When Leo states that they are friends with the humans, Genghis Frogs orders the Frog Soldiers to attack the Turtles, April, and Casey which ends with the two humans being captured. After April and Casey prove that not all humans are evil, Attila makes Napoleon the new general of the Frog Soldiers much to the dismay of Genghis.
- Rasputin the Mad Frog (voiced by Maurice LaMarche) - A member of the Punk Frogs who is Attila the Frog's right-hand frog and is named after Grigori Rasputin. He first appears in "The Croaking" where he discovers the truth behind the mutagen. When the rest of the Turtles arrive, he tries to stop Napoleon from freeing the captives, only to be knocked out. After April and Casey prove that not all humans are evil, Rasputin is present when Napoleon is made the new general of the Frog Soldiers.
- Napoleon Bonafrog (voiced by Jon Heder) - A member of the Punk Frogs who is named after Napoleon Bonaparte. He first appears in "The Croaking," where Mikey encounters him in the woods and they have a brief fight. After clearing things up, Napoleon becomes impressed with Mikey's ninjitsu and takes him to the Frog Fortress to meet his fellow frogs. Napoleon is considered to be the clumsiest of the group by Genghis, but is impressed with the information about Mikey's brothers while stating that his brothers pick on him. When Napoleon disagrees with Attila's plans, Rasputin tells him that siding with humans is treason. During the Turtles' fight against the Frog army, Napoleon frees Mikey. Later, the other Frogs see that not all humans are bad when saved by April and Casey from the fire and promotes Napoleon as the new general of the Frog Soldiers upon seeing the wisdom in him. Napoleon Bonafrog's mannerism is based on Jon Heder's character from Napoleon Dynamite.
- Frog Soldiers (Various Voices) - a group of mutant frogs led by Genghis Frog and later by Napoleon Bonafrog.
- Bernie (voiced by Bill Moseley) - A physicist who discovered the Dream Beavers forty years ago when he invented a demension-traveling device called the Dream Plug, and has been keeping himself awake since then to keep them from infiltrating his dreams. He first appears in "In Dreams," where he has become the shopkeeper of a local store. Upon learning about the Dream Beavers attacking the Turtles, he gives Casey advice on how to defeat them. After Casey destroys the Dream Plug that keeps the Dream Beavers in the Dream Dimension, it was revealed to Bernie that the Dream Beavers aren't that big on Earth. Following the Dream Beavers retreating back to the Dream Dimension, Bernie falls asleep as Casey and Donnie take him home. Both Bernie and his chainsaw are homages to The Texas Chainsaw Massacre. Bill Moseley played Chop Top in The Texas Chainsaw Massacre 2 and the blade on the chainsaw reads "The saw is family."
- Dr. Cluckingsworth, M.D. - A white chicken at the O'Neil Family summer house that develops a large brain-shaped cranium at the top of her head after ingesting the mutagen sample taken from Donnie after it leaks from Speed Demon. The resulting mutation makes her super-smart and enables her to lay mutagen eggs. She plays a key part in helping Casey and Donnie defeat Speed Demon. In "Eyes of the Chimera," she witnesses Donnie testing April's psychic powers. In "Return to New York," she helps the Turtles upgrade the Party Wagon. Later, she makes a farewell to the Turtles as she decides to stay at the farm to watch over the other chickens.
- Garson Grunge / Muckman (voiced by Nolan North in earlier appearances, and Grant Moninger in later appearances) - Garson Grunge was a humble sewer worker who had encounters with mutants in the past, such as getting attacked by Leatherhead in "It Came from the Depths," getting attacked by a Squirrelanoid at the end of "Invasion of the Squirrelanoids," getting exposed Fungus Humungous' fear spores in "Fungus Humungous," and getting controlled by one of Pizza Face's minions in "Pizza Face". In "The Noxious Avenger," Grunge is seen working as a garbage man when he hears a commotion involving the Ninja Turtles fighting Bebop and Rocksteady, and gets exposed to mutagen while investigating it. As the result of falling off the building and into the dumpster, he mutates into a 6 ft. humanoid mutant made entirely out of garbage with a banana peel cap, an exposed and eroded skeleton, a toxic vomit, garbage-controlling abilities, and dissolving abilities that Joan Grody dubs "Muckman". Muckman is convinced by Joe Eyeball to be a hero when he finds the Purple Dragons mugging a man and manages to beat them up. The man witnesses the action and talks about it to Joan Grody's show, becoming New York's new sensation. When the Turtles and April find Muckman and Joe Eyeball, Muckman blames the Turtles for his mutation yet both groups had to leave before Joan Grody could get a full glimpse of the Turtles. Upon seeing the news of Muckman, Bebop and Rocksteady plan to take advantage of this and look for him. When they find him, he thinks they are with the Turtles until they claim that they aren't with them. Muckman is convinced by them to help rob an abandoned Kraang lab claiming it contains a cure, and Joe becomes suspicious of Rocksteady and Bebop's motives. The Turtles catch up to them as Muckman begins to attack. Bebop tells Muckman to get the chemical while he and Rocksteady get the Turtles. Muckman joins the fight and the Turtles are defeated. The Turtle try to reason with Muckman but they are all knocked out by Bebop's grenade. Rocksteady throws Muckman into the lab and is blasted by the Kraang's traps. Muckman finds the chemical and is blasted by another trap. Rocksteady takes the chemical from Muckman who is then helped by the Turtles. Muckman shoots slime at Rocksteady and Bebop, who retreat when the chemicals explodes. He covers up the Turtles existence by telling Joan Grody that they were just people in costumes like the Pulverizer.
- Joe Eyeball (voiced by Grant Moninger) - A large mutant eyeball who is partners with Muckman. He starts out as the left eye of Garson Grunge before he got exposed to mutagen and turned into Muckman where Garson's left eye gained a form of it's own. Joe Eyeball acts as Muckman's conscious.
- Jason / Mondo Gecko (voiced by Robbie Rist) - Jason was a popular high school skateboarder who, while was skating his way home, was hit on the head by a canister of mutagen that was accidentally dropped from the sky by the Turtles. As the result of placing his pet leopard gecko Lars on his shoulder, he mutates into a 4 ft. humanoid mutant leopard gecko that Mikey dubs himself "Mondo Gecko", whose mutation caused him to be rejected by his parents and left homeless. He first appears in "Meet Mondo Gecko," where is taken in as an errand boy by Fishface (who was called "Mr. X" by his underlings), who exploites him into petty crimes. He tells Mondo that the Turtles are evil and he needs help capturing them. Mondo meets and befriended Mikey and Casey Jones while all three of them are skateboarding on building rooftops. After Fishface is defeated, Mondo left his services and remains friends with Mikey and Casey.
- Renet (voiced by Ashley Johnson) - A young time sorceress and the object of Mikey's amorous affections.
- Professor Zayton Honeycutt / Fugitoid - Zayton Honeycutt was an alien scientist from Dimension X reconstructed into an android.
The Foot Clan is a ninja criminal organization that was founded 1,500 years ago in Japan by an unequaled ninja named Koga Takuza when he forged an alloy stronger than steel from the stolen sacred totems of his defeated adversaries to fashion a helmet known as the Kuro Kabuto. Although wiped out after an attack on the Foot Clan monastery made by the Hamato Clan in modern times, the clan itself was restored by Takuza's last remaining descendant Oroku Saki as he takes the Kabuto for himself and rechristens himself as "The Shredder". Originally populated by only human members, the Foot had become a global network of ninja assassins. Members were trained and inducted from all forms of life, such as wealthy martial arts star Chris Bradford (Shredder's prized student) and Brazilian street thug Xever Montes. Under Shredder's guidance, the Foot Clan is currently focusing only on the blood feud between him and the last Hamato Clan leader, Hamato Yoshi (Shredder's adoptive brother) once Saki learned that he's alive in New York and training the Turtles and April O'Neil as his new ninja clan. That feud has the consequence of both Bradford and Montes getting mutated as Shredder later allies himself with the Kraang to fortify his New York army with the Foot Bots and establish an army of mutants while having former TCRI inventor Baxter Stockman (who later becomes one of these mutants) try 74 times to create and perfect the mutant army, which comes to a success upon figuring out how the mutagen works through the mutations of Russian arms dealer Ivan Steranko (Shredder's old business partner) and international master thief Anton Zeck.
- Oroku Saki / Shredder (voiced by Kevin Michael Richardson) - One of the primary antagonists of the series. Oroku Saki was the son and heir of the leader of the Foot Clan who was orphaned as a baby when his clan went extinct after their long conflict with the Hamato Clan. However, when the Hamoto Clan's leader, the father of Hamato Yoshi (Splinter), found Saki in what was left of the Foot Clan monastery, he took the poor infant into his family and raised him alongside Yoshi as another son. As they both grew older, Saki's rivalry with Yoshi intensified when they both fell in love with the same woman, Tang Shen. Fueled by jealously after Shen decided to marry Yoshi, Saki learned of his true heritage and rebuilt the Foot Clan as an armored vigilante masked by the Foot Clan's signature artifact, a helmet called the Kuro Kabuto, and armed with a pair of Tekko-Kagi claws built into his arm gauntlets known by his fellow Foot Soldiers as "the Shredder". One year after the birth of Yoshi and Shen's daughter Miwa, Shredder attacked the family in the Hamato Clan monastery, unintentionally killing Shen and furiously setting the residence in a blaze that burned his head bald and scarred. Projecting blame on Yoshi for Shen's death, he then spirited away Miwa, who he raised in the Foot Clan under the name Karai, while leaving her father for dead. Fifteen years later, in "Rise of the Turtles" Pt. 2, Shredder learns that Splinter is alive and in New York after noticing the Hamato Clan logo imprinted on a shuriken during a television news report. Seeking to finish his business with Splinter, he relocates to New York and sends the Foot Clan, under the command of Chris Bradford and Xever Montes, after the Turtles before presently facing them in person in "The Gauntlet." Luckily, overpowered by the more experienced opponent, the Turtles escape while Shredder is distracted by the mutating Montes and Bradford. In "The Alien Agenda," Shredder doesn't believe in the Kraang until Karai brings him a Kraangdroid. As Baxter Stockman gets to work on studying the technology, Shredder assigns Karai to learn more about the Kraang so that he can use whatever information is gathered about them in his war against the Turtles. In "Karai's Vendetta," Shredder interrogates a captured Kraang (even when Karai informs them on how they work their exo-skeletons) on why they have been hunting the Turtles and learns that they are protecting April O'Neil. He then sends Karai to capture April in order to draw the Turtles to him. In "The Pulverizer Returns," he decides to obtain mutagen from the Kraang so that he can transform some of the Foot Soldiers into mutants, though warned by the captive Kraang operative of unpredictable results. After the Turtles thwart the plot, the captive Kraang operative tells Shredder that they have a common enemy in the Turtles. In "Showdown," Shredder abducts April to lure Splinter to his base, delighting in the irony of his former friend's current state while revealing he handed the girl over to the Kraang. During the course of the battle, Shredder reveals the truth of Miwa's survival and that he raised her as Karai for the purpose of completing his revenge by turning her against Splinter. In "The Mutation Situation," Shredder orders some mutagen from the Kraang. After the mutagen canisters are scattered throughout the city, he plans to build his army on his own. In "Follow the Leader," Shredder leaves for Japan to take care of an urgent matter and tells Karai not to do any action towards the Turtles while he is away, which she ignores. In "Wormquake," he returns and brings Tiger Claw onto his team as his second-in-command. In "The Wrath of Tiger Claw," he sends Karai with Tiger Claw in order to find the Turtles. After Karai interferes with the mission, she is brought to Shredder by Tiger Claw to explain her treachery as she asks Splinter if he is her real father. Shredder answers yes and has Tiger Claw lock her up. In "The Legend of the Kuro Kabuto," he visits Karai in her jail cell explaining why he kept her real father a secret and hopes that she will one day understand what he had to do. After the Kuro Kabuto is stolen by Anton Zeck on behalf of Ivan Steranko, Shredder finds Zeck's calling card on a glued-down Rahzar and orders him to get everyone. After explaining the Kabuto's history, Shredder orders his minions to hunt for Zeck, sending Fishface with Stockman-Fly and Rahzar with Tiger Claw. When Leo confronts Shredder for a trade, he keeps him busy long enough for the others to get to Karai. Shredder manages to get the Kuro Kabuto back upon the Turtles' retreat. The "Karai" he trades the helmet later turns out to be a bomb as the Turtles evade it. In "Vengeance is Mine," Shredder intervenes with Tiger Claw's attempt to kill the real Karai when she tries to escape. When he tells Karai that he wants her to understand what he had to do, she furiously tells him that he is not her father. After the Turtles free her, Shredder states to Tiger Claw that she will want to have her revenge on him. When Karai returns to confront him, he manages to overwhelm and defeat her. He then plans to use her as bait so that he can have the Turtles fall into the mutagen vat filled with snake DNA that Stockman-Fly had placed in there. During Shredder's fight with Splinter, Shredder tries to stop Leo from freeing Karai only to cause her to fall into the mutagen vat and emerge as a snake-like mutant much to the dismay of Shredder and Splinter. Just as he had with Shen's death, Shredder blames Splinter for Karai's mutation as the resulting battle ends up destroying Stockman-Fly's lab. In "The Invasion," Shredder is seen sitting in his throne, thinking about the memories of him training Karai and when she got mutated. When Tiger Claw arrives, he asks him if he made his decision. Shredder says that the Kraang are dangerous allies, but they have provided the Foot with much technology and asking little in return. Tiger Claw does warn him that the Kraang will betray him, since they care nothing for the human race, but Shredder reveals he doesn't care for the humans either. He sends Tiger Claw away and contacts Kraang Prime by hologram, telling him that he will help in the Kraang's invasion in exchange that they find Karai and mutate her back to normal. After defeating Leatherhead, Shredder's fight with Splinter continues through the sewers. When Shredder takes down Splinter, he throws Splinter into the sewer dispoal pipes in front of April and the Turtles and leaves the area with a broken arm. When the Turtles and April vow to avenge Splinter, they make it to his lair in the Turtle Mech but are forced to fight Kraang Prime and escape after being defeated. In "Vision Quest," he appears as a spirit, while fighting Leo. In "Return to New York," he warns Tiger Claw to watch his tone, and reveals he knows much more about the Kraang's plan. For some reason, Shredder had other plans. He decides to destroy the Kraang and take over the city himself. While telling Tiger Claw to continue his search for Karai, a squad of Foot-Bots arrive with a restrained Splinter (who's lost his mind from the injuries). Shredder has Stockman-Fly to place him in a containment unit to have his memories restored. Later, when Mikey accidentally sets that alarm on, Shredder and his gang arrive in to see the Turtles, Casey and April with Splinter, who's mind has been restored. Shredder has his clan to go after them, but they quickly get out with the help of ninja smoke bombs. In "Serpent Hunt," Shredder has Fishface and Rahzar continue their search for Karai. At the docks, he discovers Zeck was employed by Steranko to steal his helmet, but Steranko arrives with a restrained Karai, who he promises to get back to Shredder in exchange for a way out of the city safely. After Karai and the Turtles escape, Shredder becomes furious at Zeck and Steranko for attempting to steal his helmet and hunting Karai, and proceeds to have them both mutated in Stockman-Fly's lab, despite Steranko's pleads for forgiveness, since they've known each other for about 10 years. When Stockman-Fly adds warthog DNA in the first batch of mutagen, Shredder orders Fishface to have Zeck to be mutated first for stealing the Kuro Kabuto. After Zeck is mutated, Shredder then has Stockman-Fly add white rhinoceros DNA in the second mutagen batch to have Steranko mutated for his betrayal, announcing that his animal (the rhinoceros) is apropos. Steranko still tries to convince Shredder he would be better for him as a human, but Shredder nods at Rahzar, who kicks Steranko in the second mutagen batch. In "The Pig and the Rhino," Shredder holds his ground when Rocksteady and Bebop try and get even with him for their mutation, but he easily beats them up. He then gives them the choice to either serve him or fall at his hand. Rocksteady states that he and Bebop will work for him for now as the two are sent bring Karai to him alive and warned them that failure to catch her will give them a more painful experience. After Bebop and Rocksteady succeed in their mission and returns with the caged Karai, Shredder tells her that he will find a way to cure her of her mutated state. In "Casey Jones vs. the Underworld," Shredder is accompanied by Tiger Claw and Fishface when he meets with Don Vizioso. After stating that he has control of the Russian mob through Rocksteady, the Purple Dragons and the other Asian gangs through Hun, and the South American gangs through Fishface, Shredder intimidates Vizioso by slashing his candles and meatball. This causes Vizioso to swear his allegiance to him, giving Shredder his control over the Italian mob. With the advice of Hun, Shredder plans to use the Auman Chemicals to develop a specific chemical until he ends up in a fight with Casey Jones and the Turtles. After the Turtles caused a reaction with the additive in the cheese balls and escape, Shredder states that they only delayed him as he orders Hun, Rahzar, Fishface, and Tiger Claw clean up the factory. Donatello later discovers that Shredder is working on a mind-control formula. In "Clash of the Mutanimals," Shredder has the formula complete as Stockman-Fly pours it on some worms in order to test it on Slash and Dr. Tyler Rockwell before it can be used on Karai. Then the two of them use the worms on Raph in order to have him attack the Turtles, Leatherhead, and Pete. After Leo discovers a way to break the mind-control spell by having the worms ejected from their host with the worms being destroyed in the process, Shredder takes on all of them until Slash and Leatherhead causes a statue to fall on top of him. After the Turtles and the Mutanimals retreat upon the Foot-Bots arriving, Shredder is shown to have ducked into one of the holes underneath. In "The Deadly Venom," he sends a mind-controlled Karai to attack the Turtles and their allies.
- Chris Bradford / Dogpound / Rahzar (voiced by Clancy Brown) - Chris Bradford was a world-famous martial artist who is secretly a prized member of the Foot Clan, armed with a 400-year-old katana and owning a chain of dojos across the country for the purpose of recruiting Foot Soldiers. He first appears in "New Friend, Old Enemy," where he is sent by Shredder to pair up with Xever Montes to find Splinter. After his first encounter with the Turtles, he befriends Mikey on a social media website in an attempt to entrap the Turtles, going so far as to teach Mikey his secret kata "The Death Dragon", which he learned from Shredder. Bradford later captures Mikey and baits the Turtles to rescue him and lead the Foot to Splinter. However, the plan fails after Splinter recognizes the "Death Dragon" move during the Turtles' sparring. Bradford is defeated by Mikey's use of the "Death Dragon" before he and Montes are flushed down the sewers. In "The Gauntlet," Bradford goes after the Turtles with Montes again, but fails when they are both washed away by mutagen from the Kraang's mutagen bomb on top of the Wolf Hotel. As the result of previously being bitten on the hand by Shredder's pet Akita Hachiko, Bradford mutates into an 8 ft. humanoid mutant Akita with a spiked back, a large left arm, heightened senses and superhuman strength that Mikey dubs "Dogpound". In "Showdown" Pt. 1, Dogpound reveals his own twisted knowledge of the Shredder-Splinter rivalry to Fishface, implicating Yoshi as the true instigator. Both he and Fishface are easily defeated by Splinter when he arrives to rescue April. In "Mikey Gets Shellacne," Dogpound becomes disillusioned with his mutated state and uses Karai's order to get Baxter Stockman as an excuse to force the scientist in finding a means to restore his humanity. However, a fight with Mikey in Stockman's lab causes Dogpound to fall into Stockman's mutagen tank and mutate into a near-skeletal werewolf variation of his previous form with amazing agility and projecting bony claws that Mikey dubs "Rahzar", enabling him to fight at his full potential again. But Mikey tricks Rahzar into attacking the electric system as the sprinklers go off, electrifying himself along with Fishface and Stockman. In "Wormquake," Shredder sees Bradford in new form where he states that he looks terrible. In "The Lonely Mutation of Baxter Stockman," he and Shredder confront Stockman of his miserable failure, and has his mutagen collar explode, turning him into Stockman-Fly. When Rahzar returns with a squadron of Foot Bots to see Stockman-Fly, the mutant fly quickly destroys the Foot Bots and escapes. Later, when Shredder tells Stockman-Fly to make one last mutant, Rahzar tosses a chocolate bar for Stockman-Fly to eat. In "The Legend of the Kuro Kabuto," he teams up with Tiger Claw to get the Shredder's helmet, the Kuro Kabuto. In "Vengeance is Mine," he and Fishface are distracted by Mikey's shadow puppet skills. During their fight, when Rahzar scratches Mikey on his left arm in slow motion, Mikey shouts "TO...KKA!" before he pushes Rahzar off the building into a pile of trash. In "The Invasion," he is about to attack the Turtles in front of April's apartment when Mikey pushes a couch off the second-story balcony that falls on top of him. In "Vision Quest," he appears as a spirit, while fighting Mikey. In "Serpent Hunt," he and Fishface are sent to find Karai. They then find the Turtles and Karai in a warehouse as they capture her, but their motorcycle, with Karai were in it, is stolen by Anton Zeck. Following Zeck to the docks, Rahzar fights Ivan Steranko as the Turtles and Karai escape. Shredder then has his minions take Zeck and Steranko to Stockman-Fly's lab to have them mutated. As Steranko begs for mercy, Shredder nods at Rahzar, who kicks Steranko into the second batch of mutagen, turning him into Rocksteady. In "The Pig and The Rhino," Rahzar witnesses Shredder fighting Bebop and Rocksteady for a while. In "Casey Jones vs. The Underworld," he and Fishface are stealing chemicals from the van of Aumon Chemicals when Casey attacks them. Rahzar is defeated when Raph drops a crate on him. Later, he, Tiger Claw, Fishface and Hun accompany Shredder during the visit to the Auman Chemicals factory when the Turtles and Casey arrive. Rahzar activates factory's production line and fights Mikey. In "Meet Mondo Gecko," he is seen among the viewers of the Fishface's skate race.
- Xever Montes / Fishface (voiced by Christian Lanz) - Xever Montes was a Brazilian street urchin who was left to roam the criminal underworld of São Paulo, learning for himself how to survive on his own by pick-pocketing. As he grew older, he began breaking easily into other people's homes for their valuable property, but was finally caught by the authorities during a heist on Foot Clan property and put in prison. However, this was until he was bailed out and indoctrinated into the Foot Clan by Shredder, who trained him as his street contact and a cut-throat killer armed with a pair of butterfly knives. He first appears in "New Friend, Old Enemy," where he is sent by Shredder to assist Chris Bradford in finding Splinter, since he is familiar with the criminal underworld of Manhattan. After capturing Mikey, Montes tries to trick the Turtles into leading him and Bradford to Splinter but the plan fails when they flush him down the sewers with Bradford. In "Never Say Xever," Shredder is displeased of the Foot Clan's failure of capturing the Turtles and puts them under Montes's command as a result, much to Bradford's anger. When Montes learns about the Purple Dragon's fight with the Turtles at Mr. Murakami's noodle shop, he holds Murakami hostage in order to lure the Turtles (who hold Bradford hostage in return) out into the open. He succeeds, but Fong's mercy for Leo gets him and Bradford washed off the roof. In "The Gauntlet," he goes after the Turtles with Bradford again, but fails when they are both washed away by mutagen from the Kraang's mutagen bomb on top of the Wolf Hotel. As the result of previously holding a snakehead at a Chinatown Market stall, Montes mutates into a humanoid mutant snakehead with powerful stick-like arms, fangs releasing a venom that produces fever, nausea and hallucinations, aquatic breathing, and superhuman speed that Mikey dubs "Fishface". Shortly after the mutation, Fishface is forced to reside in the pool at the Foot Clan's lair since he has a hard time breathing out of water. In "The Alien Agenda," Baxter Stockman creates a water-breathing rig and a pair of mechanical legs for Fishface that he tries to get working. In "The Pulverizer," Fisface finally gains control over his new legs when they are reversed engineered from a Kraangdroid and bites Raph in the shoulder. In "Baxter's Gambit," Raph learns more about Fishface's origin. In "Showdown" Pt. 1, Dogpound and Fishface fight Splinter when he arrives to rescue April. He is defeated by Splinter and gets knocked into the water when Shredder arrives to fight Splinter. In "Mikey Gets Shellacne," while following Karai's order to get her Stockman, Fishface witnesses Dogpound's transformation into Rahzar before they and Stockman are knocked out from electric shock. In "Wormquake!," Fishface seems to be a little scared when Tiger Claw shows up (presumably because a tiger's diet includes fish) and offers him some refreshments. When he faces Raph again, he reveals his new weapon as a larger butterfly knife called a Balisword. In "The Legend of the Kuro Kabuto," he teams up with Stockman-Fly to retrieve Shredder's helmet, the Kuro Kabuto. In "Vengeance is Mine," he is seen giving Karai awful prison food, which Tiger Claw orders him to give her. Later, he and Rahzar are distracted by Michelangelo's shadow puppet skills. Then he, Tiger Claw and some Foot-Bots chase the Turtles and Karai, but Fishface is unable to catch up after Donnie pours pizza grease on the street, making his motorcycle slip. In "The Invasion," he focuses on invading the city and fighting Leo, but is defeated. In "Vision Quest," he appears as a spirit, while fighting Raph. In "Serpent Hunt," he and Rahzar are sent to find Karai and they confront the Turtles in a warehouse before taking Karai with them. However, their motorcycle, with Karai in it, is stolen by Anton Zeck. Following Zeck to the docks, Fishface fights him as the Turtles and Karai escape. Shredder then has his minions take Zeck and Ivan Steranko to Stockman-Fly's lab to have them mutated. When Stockman-Fly adds warthog DNA in the first batch of mutagen, Shredder has Fishface shove Zeck into it turning him into Bebop. In "The Pig and The Rhino," Fishface witnesses Shredder fighting Bebop and Rocksteady for a while. In "Casey Jones vs. the Underworld," he accompanies Shredder and Tiger Claw to their meeting with Don Vizioso. During the discussion, it is revealed that Shredder controls the Manhattan branch of several South American gangs through Fishface. When at the docks with Rahzar to obtain some chemicals, Fishface fights Casey Jones until he is taken down by Raph. Later he, Tiger Claw, Rahzar and Hun are seen with the Shredder at the Auman Chemicals factory. Then the Turtles and Casey attack and Fishface fights Donnie. In "Meet Mondo Gecko," he is revealed to be the organizer of skate races in the sewers under the alias of "Mr. X". He challenges Mikey, Casey and Mondo (who previously worked for him) in the race and loses.
- Baxter Stockman / Stockman-Fly (voiced by Phil LaMarr) - Baxter Stockman was a child prodigy who tried proving his brilliance at a science fair at school by presenting a volcano with real lava, which ended up burning down the gym and getting him expelled. As he grew older, he went a lot further into his dark knowledge by getting a job as an inventor at TCRI, but was fired for spilling copier toner and ever since, he vowed revenge against those who turned his "brilliance" down. He first appears in "I Think His Name is Baxter Stockman," where he attempts to break into a building in a rudimentary battle suit. The Turtles stop him, but Stockman obtains Donnie's T-Pod, which contains a military-grade artificial intelligence chip, and incorporates it into his armor. This results in Stockman's battle armor upgrading itself until it transforms into a Stockman-made robotic being, which Mikey dubs "The StockmanPod". StockmanPod defeats the Turtles, causing them to flee. Using wisdom from Splinter about "fighting the person inside the armor", the Turtles engage the StockmanPod again, and make use of a beehive to cause the StockmanPod to fall off a building. The Turtles deactivate the T-Pod and throw Stockman in the dumpster again. In "MOUSERS Attack," Stockman is brought by Dogpound before Shredder following an incident with the MOUSERS that interferes with the Foot Clan's new plan to kill the Turtles, and Shredder spares him in return for his services that include a water-breathing rig and mechanical legs reverse engineered from a Kraangdroid for Fishface. In "Baxter's Gambit," Stockman convinces Shredder to let him execute a full-proof plan to kill the Turtles with his Maze of Doom. However, this plan is also revealed to be an attempt on the lives of Dogpound and Fishface for their abuse. Though the two groups have a ceasefire to deal with their common enemy, Stockman uses his helicopter hat to escape. In "Mikey Gets Shellacne," he goes through the remains of TCRI with the intent to start his own mutant army. However, the Turtles stop him from looking for a molecular centrifuge and leaves him to get captured by Dogpound under Karai's orders. After claiming that he can restore Dogpound's humanity, despite his transformation into Rahzar, Stockman is outfitted with a mutagen collar to make sure he does not attempt another betrayal. In "The Lonely Mutation of Baxter Stockman," Shredder becomes tired of Stockman's failure to make a mutant army with his 74th attempt being a duck that can swim, fly, and do karate. When Stockman states that he has plan to make an army of pigs and rhinos, Shredder activates the mutagen collar on him and leaves. As the result of a housefly landing on his nose before the collar explodes, Stockman mutates into a humanoid mutant housefly with a lobster-like black claw for a right hand, a vertical mouth releasing an acid that dissolves metal, heightened hearing and superhuman speed and flight that dubs himself "Stockman-Fly". As a side effect, Stockman-Fly develops a habit of collecting cravings for sugary products and spitting acid on it before consumption. After planning to make himself normal by obtaining human DNA and shutting off the power to his lab, Stockman-Fly evades Rahzar and escapes. He later interferes with the Turtles' plan to test retro-mutagen on Kirby-Bat. After the retro-mutagen falls on to a car, Stockman-Fly captures April in order to get more retro-mutagen or else April will be mutated at his lab. He brings April to his lab where she tries to fight him to no avail, but Stockman-Fly suspends her over the mutagen as a way to combine with her and become one. Leo, Donnie, and Casey Jones interfere and work to fight Stockman-Fly and free April. Rahzar joins the battle in order to claim the retro-mutagen, so Stockman-Fly competes with the Foot Bots sent by Rahzar in order to get to the retro-mutagen first. He swipes the retro-mutagen canister from the Turtles causing them to go after him while competing with the Foot-Bots. With help from Kirby-Bat, April pursues him and manages to restore her father to normal. Stockman-Fly is brought to Shredder, who wants him to make one more mutant for him. Rahzar then tosses a chocolate bar to him. Stockman-Fly sarcastically thanks Shredder for his generosity before proceeding to eat the bar. In "The Legend of the Kuro Kabuto," he partners with Fishface to retrieve Shredder's helmet, the Kuro Kabuto. During the chase, his accidental interference prompts Fishface to remark that he is such a buzz-kill, and Mikey decides that "Buzzkill" should have been a perfect mutant name for Stockman. In "Vengeance is Mine," Stockman-Fly assists Shredder in using Karai has bait so that Shredder can have the Turtles fall into the mutagen vat filled with albino horned viper DNA. This doesn't go as planned for not only did Stockman-Fly (who is startled by Shredder) allow two chemicals to accidentally mix together (which he still adds to the vat), but Karai herself falls into the mutagen vat as well. The resulting fight ends up setting Stockman-Fly's lab on fire, leaving Stockman-Fly horrified as Shredder pushes him out of the way to confront Splinter. In "Return to New York," he creates a mutagen chamber guarded by mutant clones of Shredder and connected to a computer that would enable him to sequence the collected DNA of different animals in them and is instructed by Shredder to restore Splinter's mind. He even taunts Splinter with a piece of Swiss cheese before melting it with his acid and slurping it all up before fighting the Turtles, who come in by surprise to rescue their sensei. In "Serpent Hunt," Stockman-Fly adds warthog DNA and white rhinoceros DNA in the two different mutagen batches to have Anton Zeck and Ivan Steranko mutated. In "The Pig and the Rhino," he is present when Shredder beats up Bebop and Rocksteady. It is later mentioned that Stockman-Fly has fixed Bebop's cloaking device. In "Casey Jones vs. The Underworld," he states that they don't have the equipment for Shredder's plan or the stuff to restore Karai. In "Clash of the Mutanimals," he completes the mind controlling serum which he uses on some worms and tests it first on Slash and Rockwell then on Raph. Later, he fights Pigeon Pete and loses. In "Meet Mondo Gecko," he is present during Fishface's race. In "The Deadly Venom," he is successful in restoring Karai's mind and places a mind-control worm in her.
- MOUSERS - An acronym for Mobile Offensive Underground Search Excavation and Retrieval Sentries, the MOUSERS are small robots that were created by Baxter Stockman to steal on his behalf. Stockman programs them to attack anything tagged with his radioisotope spray. The MOUSERS will attack anyone, including Baxter Stockman himself. In "Showdown" Pt. 1, two them are used by Shredder and Karai as the messengers of Shredder's message for Splinter to come out and challenge him.
- Monster of Doom - An upgraded version of the StockmanPod created by Baxter Stockman. It is first used by Stockman in "Baxter's Gambit" for his revenge on the Turtles, Dogpound, and Fishface. It took the combined strategies of both groups to defeat it.
- Tiger Claw (voiced by Eric Bauza) - Tiger Claw was a Japanese circus performer who was mutated as a child into a 6 1/2 ft. humanoid mutant Bengal tiger with razor-sharp fangs and claws, heightened smell, and superhuman strength. As he grew older, he eventually became part of the criminal underworld where he was indoctrinated into the Foot Clan by Shredder, who trained him as his bounty hunter and a master of all weapons, collecting them from most warriors he defeats. He lost his tail in battle against an as-yet-unidentified rival and searches for the person who is responsible so that he can take his revenge. He first appears in "Wormquake," where he is made Shredder's second-in-command and sent with Karai to attack the Turtles in order to draw out Splinter. After Tiger Claw defeats Raph and Mikey, Leo ends up calling Splinter on the Cheese Phone for help. Splinter arrives and fights Tiger Claw. During the fight, Karai hits Splinter with a dart with a weakening poison on it, enabling Tiger Claw to knock Splinter down and capture him. When Shredder plans to finish off Splinter, Tiger Claw shows his sense of honor by granting Splinter a final showdown with Shredder, but Leo, Raph, and Mikey are able to rescue Splinter and get him to a safe spot. While Leo, Raph, and Mikey are fighting Tiger Claw, Karai, Rahzar, and Fishface, Splinter recovers from the poison and joins the fight. During the battle, April and Casey emerge on a Kraathatrogon where it swallows Tiger Claw upon his jet pack malfunctioning. In "The Wrath of Tiger Claw," Tiger Claw returns with a torn right ear and an eyepatch on his left eye after escaping the Kraathatrogon and fighting his way through different dimensions back to Earth. Soon after he reunites with Shredder, he is sent with Karai to destroy the Turtles. During their mission, Tiger Claw states that Karai was assigned to this mission because she knows where the Turtles hang out. Together, they attack Mr. Murakami's restaurant where they get info on where to find April and Casey. While Karai goes after April, Tiger Claw goes after Casey. Casey works to evade Tiger Claw's attack, thinking that he is still mad about "the worm thing", but ends up getting thrown off the building. Tiger Claw later traces Karai to the Turtles' sewer lair and starts to head there, but she and the Turtles end up luring him to the meat locker of a factory, where the Turtles end up fighting him. When Karai arrives, she attacks Tiger Claw, but he knocks her out. He then leaves with her and informs Shredder of her actions. After Shredder confirms to Karai that Splinter is her true father, he has Tiger Claw lock her up. In "The Legend of the Kuro Kabuto," he teams up with Rahzar to get Shredder's helmet, the Kuro Kabuto. In "Vengeance is Mine," he stops Karai from escaping and has her shackled and locked up in another cell when Shredder prevents him from finishing her off. When Leo and Raph rescue her, Tiger Claw attacks them, only to be temporarily stunned by the dog whistle that Donnie sets up. He chases them in an attempt to recapture Karai, only to get knocked out by the Shellraiser. Later, Shredder has him get in touch with Stockman-Fly. Once Karai is recaptured, Tiger Claw gags her with tape and they hang her above Stockman-Fly's mutagen tank to lure the Turtles and Splinter. However, everything goes wrong when Karai gets mutated and Stockman-Fly's lab catches fire. Tiger Claw then tells Shredder to retreat with him or the whole lab will go down with him and that he won, though Shredder feels that he hasn't won with Karai as a mutant. In "The Invasion," he warns Shredder that the Kraang will "betray" him and that they don't care for the human race. However, Shredder knows that the Kraang wouldn't since he doesn't care for the humans, either. After sending Tiger Claw away, Shredder contacts Kraang Prime. During the invasion, Tiger Claw and the Foot attack the citizens and fight Leo. After he, Fishface, and Rahzar are defeated, Shredder does the honors of finishing off Leo by knocking him out. Tiger Claw then finds Leo's T-Phone ringing, allowing them to head to April's apartment. In "Vision Quest," he appears as a spirit, while fighting Donnie. In "Return to New York," Tiger Claw is not pleased of Shredder going along with the Kraang's plans, warning him about conquering humanity. Shredder warns him to watch his tone, since he had other plans to destroy the aliens and take over the city for himself. As he tells Tiger Claw to continue his search for Karai, the Foot-Bots arrive in with Splinter, who's lost his mind from the injuries he received from his previous fight. He later tries to capture the heroes in the Party Wagon, only to be blasted by fire from the deer's head. In "Serpent Hunt," he is seen standing next to Shredder. When Fishface and Rahzar fail to find Karai, Shredder threatens them to be killed by Tiger Claw if they don't continue their search because Tiger Claw is bored when he has little sport. "In The Pig and The Rhino", Tiger Claw witnesses Shredder fighting Bebop and Rocksteady for a while. In "Casey Jones vs. The Underworld" he and Fishface are present during the Shredder's visit to Don Vizioso. Later, Tiger Claw is seen on Auman Chemicals factory where he is fighting Raph. In "Clash of the Mutanimals" he meets with Fulchi twins at the docks and easily defeats the Mighty Mutanimals, leaving with captured Slash and Rockwell. Later he briefly fights Mikey only to be knocked out by Leatherhead. In "Meet Mondo Gecko" he watches Fishface's race.
- Ivan Steranko / Rocksteady (voiced by Fred Tatasciore) - Ivan Steranko was a Russian arms dealer and artifact collector with a gold tooth, a diamond right eye (which was the result of an accidental gunshot made by Anton Zeck), metal shoulder pads on his coat, and knuckle dusters (which has a picture of a hammer and a sickle on each one) who is an old friend and business partner of Shredder, known with items like Excalibur, the Spear of Destiny, Alexander the Great's armor, a polar bear hunting trophy, and a taxidermy rhinoceros in his collection, as well as the ability to tell the difference between a fake artifact and a real one. He first appears in "Enemy of My Enemy," where he meets with Shredder for a weapons deal. Shredder has the cargo searched just in case Steranko is pulling any tricks. During the Turtles' fight with Shredder, Steranko is knocked out by the weapon that is being sold to the Foot Clan. In "The Legend of the Kuro Kabuto," he sends Zeck to steal Shredder's helmet, the Kuro Kabuto, to add to the collection. When Zeck meets up with Steranko in his helicopter, they discover that Leo has swapped it out with dirty diapers. As a result, Steranko vows to hurt Zeck for it. In "A Chinatown Ghost Story," it is mentioned that Steranko would pay the Purple Dragons through the roof for the Mystic Dagger. In "Serpent Hunt," both he and Zeck are trying to get out of the city and away from the Kraang. In order for them to do that, they will use Karai as a request in exchange for Shredder granting them a way out. Later, they fight the Turtles, who are trying to find Karai as well. After Zeck successfully steals Karai and the motorcycle from Fishface and Rahzar, Steranko contacts Shredder as Zeck notices a spy-roach on him. At the docks, they proceed to make the deal with Shredder until the Turtles arrive. After Karai escapes and the Turtles get away safely, Shredder has Fishface and Rahzar take Zeck and Steranko to Stockman-Fly's lab. At the lab, the two see their names with a picture of them next to the animal they're going to transform into as Rahzar taunts them. Shredder, however is furious at his old friend for sending Zeck to steal his helmet and hunting Karai, but Steranko pleads him to forgive him since they've known each other for about 10 years. After Zeck is mutated, Shredder says to Steranko that his animal is apropos, though Steranko still tries to convince him to spare him because he would be much better as a human to work for him instead of a mutant. However, Rahzar kicks him, making him lose his Ushanka and coat as he falls into the second batch of mutagen within the mutagen vat. As the result of Stockman-Fly pouring white rhinoceros DNA into the vat, Steranko mutates into a large humanoid mutant white rhinoceros (though the form has the mouth of a black rhinoceros) with a jagged horn used as a sword, superhuman strength and speed, and the tops of his knuckle dusters and shoulder pads (which end up assuming a different shape and growing a third spike on each) fused onto his skin that Mikey dubs "Rocksteady". Shortly after the mutation, Rocksteady wears only a yellow tank top, brown bandoliers, and camouflage pants that somehow appeared on him after the mutation. In "The Pig and the Rhino," he and Bebop try to get even with Shredder for causing their mutation only to be beaten up by him. Shredder offers the duo a choice to either serve him or fall at his hand. Rocksteady states that they'll follow him for now as the two are sent out to find Karai where the failure will be them having a more painful experience. However, Rocksteady and Bebop divert from their mission to get revenge on the Turtles. After Bebop captures Donnie and April, he uses Donnie's phone to tip off Rocksteady to where the others might be. Rocksteady attacks Raph and Casey Jones outside the movie theater and manages to defeat them. When the two converge at an amusement park called Coney Comet, Leo works to free the captives while Mikey stalls the captors by deciding their mutant names. While Steranko liked the Rocksteady name, Anton Zeck didn't like the Bebop name. After April, Casey, Donnie, and Raph are freed, a fight breaks out and Rocksteady is struck by a roller coaster, but he and Bebop eventually get away. They later successfully catch Karai and bring her back to Shredder in a cage. In "Casey Jones vs. the Underworld," it is mentioned by Shredder during his meeting with Don Vizioso that he controls the Manhattan branch of the Russian mob through Rocksteady. In "The Noxious Avenger," Rocksteady and Bebop are sent on an errand run to obtain chemicals from an abandoned Kraang lab for a mind-control serum that Stockman-Fly is working on for Shredder. When the Turtles come to stop them, Rocksteady reveals his new weapons as larger brass hammer and sickle similar to the ones on his knuckledusters, and the resulting fight causes a canister mutagen to fall on top of Garson Grunge and turn him into Muckman. After learning of Muckman on TV, he and Bebop manage to trick him into helping them obtain the remaining chemicals at the Kraang lab, but Muckman turns on them and destroys the chemical, causing Rocksteady and Bebop to retreat. In "Meet Mondo Gecko," Rocksteady is seen among the spectators of Fishface's race. In "The Deadly Venom," Shredder has a mind-controlled Karai attack him for hunting her.
- Anton Zeck / Bebop (voiced by J.B. Smoove) - Anton Zeck was a professional thief in a high-tech suit with a purple X-ray visor and armed with high-tech gadgets such as a cloaking device (which is run by Double A batteries), an energy Mohawk, a sliding backpack, a tub of glue, a laser belt, and shurikens that explode into microchips, who was indoctrinated into the employment of Ivan Steranko, whose right eye he shot out by accident in an earlier encounter. He first appears in "The Legend of Kuro Kabuto," where he is sent by Steranko to steal Shredder's helmet, the Kuro Kabuto. Following his theft, where he leaves his calling card on a glued-down Rahzar, Zeck runs into the Turtles, who steal the Kabuto from him. The Turtles, Rahzar, Fishface, Tiger Claw, and Stockman-Fly fight Zeck over the helmet, but he manages to evade them. When Zeck meets up with Steranko in his helicopter, they discover that Leo has swapped it out with dirty diapers at the last minute. As a result, Steranko threatens to pop Zeck's face like blueberry. In "Serpent Hunt," Zeck is seen starving after having to have not eaten in days since the Kraang invasion and can only afford on a dead cockroach that he covers in ketchup, which is taken from him and eaten by Steranko as they plan to get out of the city and away from the Kraang. In order to do that, they need to capture Karai and have Shredder get them to safety in exchange for her. Later, they fight the Turtles, who are searching for her as well, but she manages to avoid them. After Zeck steals a motorcycle, with Karai on it, from Rahzar and Fishface, he brings her to Steranko, who he notices some spy-roaches on while they are contacting Shredder. At the docks, Zeck comes face-to-face with Shredder as Steranko arrives with Karai. Later, the Turtles and Karai escape, and Shredder, knowing that someone else has to pay for what has happened, has Fishface and Rahzar take the two to Stockman-Fly's lab. At the lab, Zeck is terrified and tells Steranko that he doesn't want to be a mutant because he's too handsome. When Shredder returns, he is furious at them for stealing his helmet and hunting Karai, and has Fishface shove Zeck into the first batch of mutagen within the mutagen vat. As the result of Stockman-Fly pouring warthog DNA into the vat, Zeck mutates into a tall and thin humanoid mutant warthog with a short left tusk, heightened smell, superhuman strength, and the high tech parts of his suit fused onto his skin that Mikey dubs "Bebop". In "The Pig and the Rhino," he and Rocksteady try to get even with Shredder for causing their mutation only to beaten up by him. Shredder offers the duo a choice to either serve him or fall at his hand. Rocksteady states that they'll follow him for now as the two are sent out to find Karai where the failure will be them having a more painful experience. However, Bebop and Rocksteady divert from their mission to get revenge on the Turtles. Bebop tracks Donnie and April in the alley near the local dry cleaners and is able to subdue them. During the fight, he mentions that Stockman-Fly has fixed his cloaking technology. Using Donnie's phone, he tips off Rocksteady right to where the other Turtles may be found. When the two converge at an amusement park called Coney Comet, Leo works to free the captives while Mikey stalls the captors by deciding their mutant names. While Steranko liked the Rocksteady name, Anton Zeck didn't like the Bebop name. After April, Casey, Donnie, and Raph are freed, a fight breaks out and Bebop is taken down by Donnie with a smoke bomb, but he and Rocksteady eventually get away. They later successfully catch Karai and bring her back to Shredder in a cage. In "The Noxious Avenger," they are sent on an errand run to obtain chemicals from an abandoned Kraang lab for a mind-control serum that Stockman-Fly is working on for Shredder. When the Turtles come to stop the, the resulting fight causes a canister of mutagen to fall on top of Garson Grunge and turn him into Muckman. After learning of Muckman on TV, Bebop and Rocksteady manage to trick him into helping them obtain the remaining chemicals, but Muckman turns on them and destroys the chemical, causing Rocksteady and Bebop to retreat. In "Meet Mondo Gecko," Bebop is seen beside Rocksteady watching Fishface's race.
- Don Vizioso (voiced by Brian Bloom) - Don Vizioso is a crime lord of an Italian mafia branch who is an old business partner of Shredder. He owns an unnamed restaurant somewhere in Manhattan. He first appears in "Casey Jones vs. the Underworld" where Shredder meets with him at his restaurant. When Shredder mentions mentions that the Kraang's invasion has the power in the Manhattan underworld shifted over to the Foot Clan, Tiger Claw, Fishface, and the Falchi Twins to prepare to attack. Both sides stand down as Vizioso asks Shredder to explain what he means by the power shifting to the Foot Clan. After mentioning that he controls the Russian mob through Rocksteady, the Purple Dragons and other Asian gangs through Hun, and the South American gangs through Fishface, Shredder proves his point that he needs control over the Manhattan branch of the Italian mob through Vizioso by slicing the candles and the meatball on his fork. This convinces Vizioso to swear his allegiance to him. In "Meet Mondo Gecko," Don Vizioso (alongside the Fulchi Twins) was seen amongst the audience of villains watching Fishface's race against Mikey, Casey, and Mondo Gecko.
- Fulchi Twins (voiced by Eric Bauza) - A pair of twin brothers who work for Don Vizioso. They first appear in "Casey Jones vs. the Underworld," standing on both sides of Vizioso during his meeting with Shredder. In "Clash of the Mutanimals," the secure the final component chemical for Shredder's mind-control formula and give it to Tiger Claw when meeting him at the docks, and retreat as Tiger Claw deals with the Mutanimals. In "Meet Mondo Gecko," they are present with Don Vizioso during Fishface's race as Vizioso's bodyguards.
- Shredder Mutants - A trio of mutant crustacean-like clones of Shredder created by Stockman-Fly to serve as the guards of the Foot Clan's lab. While Mikey fights Stockman-Fly, the others fight the Shredder Mutants. Once Splinter manages to regain his mind, he defeats the Shredder Mutants by kicking them into the giant fan below. In "Meet Mondo Gecko" their silhouettes are seen among the audience during the race.
- Shiva Shredder (voiced by Kevin Michael Richardson) - A large four-armed clone of Shredder who was created from the DNA of Shredder and a crab which also gives him a crab shell.
- Claw Shredder (voiced by Kevin Michael Richardson) - A clone of Shredder who was created from the DNA of Shredder and a lobster which also gives him lobster-like claws and tail.
- Mini Shredder (voiced by Kevin Michael Richardson) - A miniature clone of Shredder who was created from the DNA of Shredder and a shrimp which also gives him a shrimp moustache and a shrimp tail.
- Foot Soldiers - An army of ninjas loyal to Shredder, making up the soldiers of the Foot Clan. They wear black suits and masks with bug-like eyes and red bandannas with the Foot Clan logo on them (similar to the outfits worn by the Foot Ninjas from the Teenage Mutant Ninja Turtles films). The Foot Soldiers seem to never talk. Each of the Foot Soldiers fight with staffs, shurikens, katanas, Naginata, Tonfa, and nunchucks. The Foot Soldiers recruits are trained at Chris Bradford's dojos. At the time when Shredder was in Japan, the Foot Soldiers haven't been seen since the Foot Bots came into view. In "Vision Quest," the Turtles encounter spirit versions of the Foot Soldiers in their spirit quests.
- Foot Bots - An army of robotic Foot Soldiers created by the Kraang to strengthen the Foot Clan. The Foot Bots are capable of adapting to the skills of other ninjas. During the Turtles' first fight with the them in "Follow the Leader," the Turtles had to do unpredictable moves and skills to defeat them. In "Target: April O'Neil," the Foot Bots are upgraded with two extra retractable arms with weapons protruding from where the hands would be. They learn how to ice skate among other things as seen when they face off against Casey Jones at the ice skating rink. In "The Lonely Mutation of Baxter Stockman," the Foot Bots are shown to have gliding abilities with retractable fabric wings.
- Chrome Dome (voiced by Nolan North) - A Foot-Bot in a dark ninja outfit (which resembles Chris Bradford's full ninja outfit) armed with a plasma sword and whip that was originally built by the Kraang to keep the Foot Clan sufficient with their invasion plan. It first appears in "Target: April O'Neil," where it is used by Karai in her plan to kill April. During the Foot Clan's fight with the Turtles, Chrome Dome snatches April from her duel with Karai and reveals that the Kraang has programmed it to follow their plan to reserve April, now viewing both sides as its enemy. Mikey is able to defeat it by running it's plasma sword through its chest. In "Vengeance is Mine," another Chrome Dome is used by Shredder as a decoy in order to capture Karai. This Chrome Dome is destroyed by Karai.
The Kraang (voiced by Nolan North) are a race of brain-shaped aliens from Dimension X piloting robotic bodies called Kraangdroids that are responsible for bringing mutagen to Earth a thousand years ago. They have not mastered English and communicate in redundant speech. In "The Gauntlet," the Turtles learn that the Kraang have been abducting scientists so that they can help modify the mutagen's properties. In "The Alien Agenda," the Kraang establish the World Wide Genome Project as a front while they were collecting the DNA of every animal and plant species on Earth. In "The Pulverizer," the Kraang reclaim the power cell that Leatherhead stole from them. In "TCRI," it is revealed that the Kraang have their headquarters in the higher parts of the TCRI building. It is also revealed that the Kraang can also survive in poisonous gas. While inside the TCRI building, the Turtles discover the Kraang's invasion plan: to mutate the whole planet so that their kind can live here, which will wipe out everyone else in the process. When the Turtles manage to get away when their explosives are unable to destroy the Kraang's portal, Mikey manages to obtain a Kraang data storage device which reveals that the Kraang are also after April. In "Cockroach Terminator," the Kraang steal a special lens as part of a plot to use their laser drill to burrow to the Earth's core as part of the Kraang's invasion plan. This plot is thwarted by Raph. In "Enemy of My Enemy," two Kraang operatives pilot a Kraang scout ship as a means of hunting the Turtles up to the point where they end up crashing a weapons trade involving the Shredder. The spacecraft is repelled by Leo and crashes into the harbor, almost dragging Shredder down with it. After he and Karai emerge from the water, Shredder is shown to have captured one of the Kraang pilots. In "Karai's Vendetta," the captured Kraang is interrogated by Shredder on why they hunt the Turtles and learns on how they've been targeting April. The Kraang set up a base in the East River where they start a plot to turn Earth's water into Kraang water and have brought a large unnamed sea monster from Dimension X to help guard the base. The Turtles managed to destroy the base and escape from the sea monster. In "The Pulverizer Returns," the captive Kraang agent tells Shredder that the mutagen that had mutated Chris Bradford and Xever into Dogpound and Fishface has unpredictable results on Earth. After Shredder's mutagen plot is thwarted by the Turtles, the captive Kraang tells Shredder that they have a common enemy in the Turtles which leads to an alliance between the Foot Clan and the Kraang. In "Showdown" Pt. 1, the Kraang begin their invasion by bringing the Technodrome to Earth. Even though the Turtles destroyed the portal, the Technodrome and Kraang Prime have already arrived. In "Showdown" Pt. 2, the Kraang start to collect human specimens for Kraang while Kraang Prime begins to siphon the mental energy from April, but this plot is thwarted by the Turtles. In "The Kraang Conspiracy," the Kraang are shown to have used the energy to create clones of April, including a derp one, but they need a sample of her DNA to perfect them and the mutagen. This plot is however thwarted by April (with the Turtle's help) when she uses her mind to deliver a psychic blast to the clones, destroying them. In "Plan 10," the Kraang develop a mind-swapping device in order to swap the minds of anyone which results in Raph and a Kraang getting their minds switch. After the mind-swap is undone, the Turtles destroy the device. It is also revealed that the Kraang are going to invade Earth with a lot of Kraang soldiers. In "Buried Secrets," it is revealed that the Kraang were awakened at the site of the O'Neil Family's summer house by April's great-grandfather which explained why the Kraang have been targeting April ever since they abducted her mother. They also created a failed infiltration creation using the DNA of a Kraang and April's mom which was too dangerous for them.
- Kraang Prime (voiced by Roseanne Barr) - A 25 ft. brain-shaped alien who is the leader of the Kraang and one of the primary antagonists of the series. When he speaks to other Kraang, he uses redundant speech, but when speaking to anyone else, he uses normal speech. He first appears in "Showdown" Pt. 1 where he tells the rest of the Kraang that the invasion of Earth should begin now as the Technodrome will appear in six hours. Kraang Prime arrives on Earth in the Technodrome. In "Showdown" Pt. 2, he confronts April O'Neil after is captured and states that she has the mental energy needed to transform the Earth so that the Kraang can live on it. Kraang Prime then proceeds to begin siphoning the mental energy from April. As soon as Kraang Prime obtains enough of the mental energy, he begins his plot to mutate the Earth. However, the Turtles arrive to fight Kraang Prime and thwart his Earth mutation plot. Kraang Prime then emerges in a giant robotic body and chases after them. Leo manages to hold him off while the others get away. Luckily, Leo manages to escape with the captive humans as the Technodrome falls into the ocean. In "The Kraang Conspiracy," Kraang Prime is seen in a hologram without his robotic suit, telling the Kraang about his plan with the mutagen and catching April spying on him. In "Plan 10," he is telling two Kraang about swapping minds with humans and invasion, but becomes suspicious about one of the Kraang (which has Raph's mind swapped into it) being a little strange. Kraang Prime also states to the Kraang operatives that he has a lot of Kraang soldiers ready for the next invasion. In "The Invasion," he contacts Shredder and asks him if he's made his decision. When Shredder asked if he helps him and will uphold his end of the bargain, Kraang Prime says he will deliver Splinter and the Turtles to him to have them be killed. When Shredder asked him if he will mutate Karai back to normal once he finds her, Kraang Prime agrees to the terms. In return, he wants Shredder and his clan to help him conquer New York City and then the world. Later, he and his army mutate several humans into Kraang-like creatures and two pigeons into Rocktopus' attachment. He prepares to kill Raph and Casey, but is shortly stopped by the Earth Protection Force. Later, he mutates Kirby into a Kraang-like creature and chases the Turtles, Casey and April in the Party Wagon. Later, he fights the Turtles and April in the Turtle Mech. During their fight, Kraang Prime reveals that he and his army are the ones responsible for the human race. He claims that he and his army mutated the monkeys into humans. He is then defeated when he gets electrocuted with power siphoned from the city's power grid that results in it going down. Kraang Prime then comes out of his robotic body and proceeds to pursue them, but fails when the Turtles and April get away in the Party Van driven by Casey.
- Kraang Subprime (voiced by Gilbert Gottfried) - A Kraang spy with a robotic left eye, a huge scar, a blue tattoo across his right eye, and a robotic claw on his left front tentacle who poses as Irma Langinstein (voiced by Kate Micucci), April O'Neil's best friend in high school. She seems to be a lot more serious than her 1987 incarnation; though she retains the glasses from her previous incarnation, she is more gothic than nerdy. In "Mousers Attack," she calls April when her phone is stolen by the Purple Dragons. In "Mutagen Man Unleashed," she is shown as a background character, but her face is not seen. In "The Good, The Bad and Casey Jones," she makes her first introduction appearance when she and April both discover the bruises on Casey's face. When Irma ask Casey how he got them, she makes a suspicious "Hmm?", though Casey seems annoyed and angrily asks her if she's his interrogator. This makes Irma upset and she tells April to leave for the exam and not be late. In "Of Rats and Men," she has pizza with Casey and April. She seems disappointed that the people claim that pizza was gluten-free, but she claims to have definitely tasted gluten. Casey thanks her for hanging with them on their "date", since they really need a chaperon. When Casey gets spooked by a rat, Irma laughs about someone as big as him for being scared of a little rat. April then spots a stray cat (which would later become Ice Cream Kitty) and decides to find it a home. Irma states that rats are relatively harmless, and explained that they also share many human similarities, which is why they are used in scientific experiments. She doesn't intend to keep the cat, because she's more of a "rat person". She then hears a strange noise behind her, but doesn't seem to see anything watching. When April and Casey leave with the cat, Irma is disappointed that they ditched her again. She says to herself that she'll one day find out where the two are always running off to, which possibly hints that she may encounter the Turtles in a future episode. Suddenly, a strange mutant (later revealed to be a giant rat), that has been spying on her, appears and roars, then Irma turns around and screams in horror as it seemingly attacks her. Later, it is discovered that Irma is captured (along with Casey and several other people) by The Rat King's army of giant rats. The Rat King decides to test his new serum on Irma after the previous mutagen serum is not perfected. However, the Turtles, Splinter and April (even Ice Cream Kitty) find him and April manages to release Casey, Irma and the citizens. When they head to the surface, one of the giant rats attacks April, Irma, and Casey; but the rat is taken out by Casey. In "Pizza Face," she insist that April should watch a scary movie with her, but April lies to her that she has a date with Casey, though Irma doesn't believe the "dating with Casey" excuse. She is also suspicious and wandering about her "secret friends" that she won't let her know, which may be a clue that she'll know the Turtles. Then, she and April accidentally get bumped into a pizza delivery guy, who exclaims that he's being attacked. April leaves with a box of pizza the guy drops, which makes Irma sad that April left with no honest reason. In "The Wrath of Tiger Claw," Irma watches a movie with April and Casey. When April senses that they're being followed, they intend to split up. Once again, they leave Irma, who gets confused about what April was talking about. She is frustrated at them for leaving her again. In "A Chinatown Ghost Story," she and April are captured by the Purple Dragons under Ho Chan's orders. Irma is seen without her glasses when Ho Chan removes them, claiming that she has some sort of power within her. After Ho Chan is defeated, Irma arrives and instead of letting her know who they are, the Turtles leave the scene. In "The Invasion," April decides to let Irma know who her friends are. They are then attacked by Foot-Bots, but they managed to hide in the sewers. However, once they arrive, Irma begins to act strange. Her face starts twitching, her neck expands to reveal a robotic neck. Mikey becomes horrified as he accidentally throws his slice of pizza at Irma, making her eyes glow red while repeatedly saying, "Turtles!" As everyone becomes horrified, Irma expands her body to reveal that she's been a robot the whole time. Then, Kraang Subprime peers out from inside the robot as he laughs evilly. April becomes extremely terrified that Irma was a Kraang as the alien spy throws the arcade set. Kraang Subprime reveals that he's the greatest Kraang spy in all of Dimension X, and that the discovery of the lair was the final component needed to launch full-scale invasions as several portals open to allow several Kraang-droids to enter. April says to herself that the whole thing was messed up about her best friend from the past year being a Kraang, and Kraang Subprime cheerfully says he fooled her and everyone else. He tells the Kraang to destroy the Turtles and wipe out the lair, but says that Splinter comes with them. During the fight, Kraang Subprime pursues the Turtles and fights Splinter. Irma's head was severed from his robot suit, which operates itself and attacks Mikey and Donnie. Leo destroyed the head by impaling it with his katana. Splinter holds off Kraang Subprime and biding his sons and April to escape. Later, he is defeated by Splinter, who destroys his robotic suit and knocks him off. Kraang Subprime vows that the Kraang will dominate the Earth and tells Splinter that he and his children will be destroyed. Before he could say anything else, the stairs fall and crush Kraang Subprime, presumably killing him. His tentacle limps before laying motionless. In "Battle for New York" Pt. 1, he survived his apparent death and his Irma-Bot suit is rebuilt. He plans to set the mutagen missile to mutate everyone in the world, but is also annoyed when the Kraang judge the way he speaks which caused him to kill one of them. When the Mighty Mutanimals attack, Kraang Subprime managed to set off the missile with the Turtles on it. After the missile was stopped, Kraang Subprime was forced to temporarily retreat. In "Battle for New York" Pt. 2, Kraang Subprime follows the Turtles to Dimension X, after a fight with the Turtles, Kraang Subprime summons the Kraang to send the Dracobot after the Turtles. Later, he attacks the Turtles in a different Technodrome, shouting "Here's Kraangy!" as more Kraang-droids come in. However, after the Turtles succeed their mission and are teleported to safety by Dr. Rockwell, Kraang Subprime is left stranded in the Technodrome as it crashes. The head of his Irma-Bot suit begins to float around.
- Mrs. Campbell (voiced by Cassandra Peterson) - A research scientist from the World Wide Genome Project who takes an interest in April O'Neil. She is actually an android created by the Kraang who used the World Wide Genome Project as their front. When she was pursuing April, she ends up fighting the Turtles until her face is sliced off and is then shorted out by water from a nearby water fountain. Another robot of Mrs. Campbell was seen as the receptionist at TCRI. This time, she and the Kraang operatives were taken out by Leatherhead. The same Mrs. Campbell makes an appearance in "Showdown" Pt. 1 where she and the Kraang are taken out by Metalhead at TCRI. Another Mrs. Campbell has an appearance in "The Kraang Conspiracy" where she attacked the Turtles and allowing one of the Kraangdroids to capture April. She was defeated when Raphael threw one of his sais at one of her missile-launching elbows, causing her to explode. She returns in "Battle for New York" Pt. 2, where she sends Irma-Bots after the Mighty Mutanimals. When she threatens to kill the Mutanimals if he doesn't surrender, Slash finally gives in as Mrs. Campbell closes the portal. Later, the Mutanimals broke free and Rockwell was about to be shot by Mrs. Campbell, but Slash saves him by throwing his mace at Mrs. Campbell, destroying her.
- Biotroid - A Yeti-type bio-mechanical suit with powerful arms, blades on its nipples and butt cannons, making it a very awkward villain. It is first used by the Kraang in "The Mutation Situation" on the Kraang stealth ship to protect the shipment of mutagen from the Turtles, with the resulting battle causing the mutagen canisters to fall onto the streets, one of which causes Kirby to mutate into Kirby-Bat when he tries to protect April from the mutagen. It is defeated by the Turtles and the stealth ship is redirected towards the moon. More Biotroids appear in "Wormquake," where two of them are piloted by the Kraang to attack Donnie, April, and Casey during their investigation on a portal to Dimension X. They return in "Battle for New York" Pt. 1 where armies of them have been made.
- Dracodroid - A two-headed cyborg dragon creature created by the Kraang. It serves as their mode of transportation.
- Irma-Bots - A bunch of androids that resemble Kraang Subprime's Irma Laginstein disguise. In "Battle for New York" Pt. 2, they accompany Mrs. Campbell against the Mighty Mutanimals.
Dimension X creatures
The Kraang have used various creatures that come from Dimension X to help them in their plots. Among the Dimension X creatures are:
- Rock Soldiers - A duo of nearly identical 20 ft. rock monsters from Dimension X with regenerating abilities who serve the Kraang as guards.
- Traag - A 20 ft. lava-spewing rock monster from Dimension X with regenerating abilities who is in service to the Kraang.
- Granitor - A 20 ft. blue fire-spewing rock monster from Dimension X with regenerating abilities who resembles Traag (but is pale pink in color) and is in service to the Kraang.
- Dimension X Sea Monster - An unnamed alien sea creature from Dimension X resembling the Loch Ness Monster that acts as an underwater guardian for the Kraang.
- Kraathatrogons - A race of 100 ft. alien worms from Dimension X with antennae used as riding reins that the Kraang "milk" for mutagen.
- Rocktopus - A giant octopus/insect-like alien from Dimension X that sports a small creature-like attachment to draw in its prey.
- Living Atoms - A group of sentient large atoms from Dimension X that shoot a bolt of electricity. They first appear in "Into Dimension X," where they attack the Turtles until they finally manage to outrun them.
- Bio-Electrical Eyeball - A gigantic sun-size eyeball from Dimension X that shoots electricity at its enemies. It first appears in "Into Dimension X," where it blows up a nearby ship with electricity.
The Purple Dragons are a street gang that has been extorting shop owners for protection money in the Lower East Side and Chinatown. Most of them are Chinese-Americans who secretly became allies with the Foot Clan and are commanded by Rahzar and Fishface. In "A Chinatown Ghost Story," they rob a museum to obtain specific artifacts for Ivan Steranko only to be thwarted by Donnie, April, and Casey. However, they do manage to get away with a dagger that contains Ho Chan's ghost as he temporarily makes them his servants.
- Hun (voiced by Eric Bauza) - The new leader of the Purple Dragons. Unlike previous incarnations of the character, Hun is a slender-shaped Chinese-American man (closely patterned after Bruce Lee) who wears yellow shades, sports a half-opened shirt, a gold medallion, rings with spikes on them, and a big Purple Dragons icon tattoo on his left arm. He first appeares in "Casey Jones vs. the Underworld," where he helps his fellow Purple Dragons rob a bank. He manages to outfight Casey Jones and gets away with the Purple Dragons as the police arrive. It is mentioned that Hun has officially aligned with Shredder during his meeting with Don Vizioso where Hun was also able to get the other Asian gangs on Shredder's side. Hun later brings the chemicals that Shredder was looking for and suggests that Shredder should take over the abandoned Auman Chemicals (where the chemicals were obtained from) since it's on the Purple Dragons' turf. At the factory, Hun suggests that the Purple Dragons run the factory. While the other Turtles fought the Foot Clan, Casey faces off against Hun and knocks him into a cheese vat. After the Turtles caused a chemical reaction to the chemical with the additives used in the cheese balls, Shredder states to Hun, Rahzar, Fishface, and Tiger Claw that the Turtles have only delayed him. In "Meet Mondo Gecko," he and his gang encounter Mikey, Casey and Mondo Gecko and watch Fishface's skate race.
- Fong (voiced by Andrew Kishino) - The unofficial leader of the Purple Dragons in Season 1 and 2 (unless Rahzar and/or Fishface is present) who is sometimes armed with a butcher knife. In "A Chinatown Ghost Story," Ho Chan's ghost briefly gives him lightning-based abilities. Staff writer Kenny Byerly named Fong after Benson Fong, an Asian actor from the 1960s who appeared in such films as The Love Bug and Flower Drum Song.
- Sid (voiced by Andrew Kishino) - A large Chinese-American member of the Purple Dragons who is sometimes armed with an axe. In "A Chinatown Ghost Story," Ho Chan's ghost briefly gives him thunder-based abilities. Sid was named by show writer Jeremy Shipp.
- Tsoi (voiced by James Sie) - A moustached Chinese-American member of the Purple Dragons who is sometimes armed with a sledgehammer. In "A Chinatown Ghost Story," Ho Chan's ghost briefly gives him wind-based abilities. He is named after Andrea Tsoi, a friend of show writer Kenny Byerly's.
- Snake / Snakeweed (voiced by Danny Jacobs) - Snake was a Caucasian-American street thug working for the Kraang as their getaway driver, who the Turtles catch and interrogate to find out where the Kraang are holding April and Kirby O'Neil. After getting away from the Turtles upon answering them, Snake meets up with the Kraang at their hideout and warns them that the Turtles are coming. During their mission to rescue the O'Neils, the Turtles crash a truck full of mutagen into the Kraang base where the mutagen heads straight towards him. As the result of falling off balance into a field of ivy weeds, Snake mutates into a 12 ft. regenerating humanoid mutant ivy weed with a hundred leaf-handed vines for arms, a hole in its neck showing his heart and a stem that splits in half to use as legs that Mikey dubs "Snakeweed". While the rest of the Turtles fight Snakeweed, Leo lures him into a power core where he is electrocuted and blown up. After the Turtles leave, Snakeweed's heart starts beating again. In "New Girl In Town," he returns and is abducting people to use them as fertilizer. At the end of the episode, the Turtles fight him again. He is eventually frozen and shattered into pieces, but his heart starts beating once again. In "Metalhead Rewired," Snakeweed is among the mutants captured by Kraang in order for them to control them. He is first discovered in his cell by the Turtles, then he and Spider Bytez are released by the Kraang to attack the Turtles. Luckily, Metalhead frees them from the Kraang's control, and they attack the Kraang, having no intentions of harming the Turtles. Snakeweed then briefly aids the Turtles before making his way to escape. With help from Metalhead, the Turtles frees the captive mutants and they escape through the portal. In "Meet Mondo Gecko," he is seen among the audience of Fishface's race at the time when Fishface was racing against Michelangelo, Casey Jones, and Mondo Gecko.
- Vic / Spider Bytez (voiced by Lewis Black) - Vic was a crabby New Yorker in his 40s who videotapes the Turtles on his cell phone during a rooftop battle with the Kraang after one of the Turtles accidentally knocks down his satellite dish. Calling the Turtles "Kung Fu Frogs", Vic also insults Raph, causing him to lose his temper. When Vic attempts to sell his video to the Kraang, they kidnap him. Leo, Mikey and Donnie attempt to rescue him, but he gets splashed with mutagen in an attempt to get his phone back. As the result of being bitten in the finger by a red spider that crawls onto the phone, Vic mutates into a humongous, round humanoid mutant black spider with red and orange markings, short arms and legs, agile arachnid legs for hair, and a huge fanged mouth releasing an acid that dissolves metal that Mikey dubs "Spider Bytez". Spider Bytez blames the Turtles for his mutation and attacks them. During the battle, his cell phone is destroyed. Just when Spider Bytez has the advantage, Raph shows up and gains control over his temper. Spider Bytez escapes, vowing to get revenge on the Turtles later. In "Metalhead Rewired," Spider Bytez is among the mutants captured by Kraang in order for them to control them. He is first seen in the sewers, being chased by the Kraang, and begging for the Turtles to help him. The Kraang manage to capture him, then they lock him in a chamber and brainwash him. Then, Spider Bytez and Snakeweed are released to destroy the Turtles, but Metalhead frees them. Spider Bytez is last seen with Pete and Slash as they head for the portal. With help from Metalhead, the Turtles free the captive mutants and they escape through the portal. In "Meet Mondo Gecko," he is among the audience of Fishface's race at the time when Fishface was racing against Michelangelo, Casey Jones, and Mondo Gecko.
- Dr. Victor Falco / Rat King (voiced by Jeffrey Combs) - Victor Falco was a scientist presumably working for the Kraang on an experiment involving mutagen and monkey DNA. Believing that he was close to developing a neurochemical that could make him psychic, Falco tests the chemical on his neurochemist colleague Dr. Tyler Rockwell, mutating him into a humanoid mutant monkey that can read emotions. After the Turtles figure out that Falco was lying about Rockwell's involvement in the research, they confront him. Falco injects himself with the chemical, which gives him the ability to predict the Turtles' every move. Donatello figures out how to close off his mind from Falco to defeat him. Falco escapes before the Turtles can interrogate him about the Kraang's plot. In "I, Monster," he is destitute but has salvaged some mutagen and has recreated the psychic chemical in his rat-infested lab. An accident with the chemical makes his body into a corpse-like state as well as gives him psychic control over rats who help him out of the rubble caused by the explosion. While taking over all the rats in the city including Splinter upon donning some bandages, a brim hat, and an overcoat, Falco dubs himself "The Rat King" and attempts to take over New York with his legion of rats. He manipulates Splinter into fighting the Turtles, but Splinter frees himself from the mind control and defeats him. The rats then swarm over Rat King's unconscious body to get him away from the Turtles. In "Of Rats and Men," the Rat King resurfaces and has his giant rats attack Manhattan while trying to control Splinter again. The Rat King does peer into Splinter's mind to get what he needs. The Turtles end up fighting the Giant Rats as they are abducting humans with one of them being Irma. In Rat King's lair, Rat King tells the captives that he created the Giant Rats from the Mutagenic Growth Serum so that he can use the mutagen to turn the captive humans into Rat People. Though Rat King has had some failed experiments in the past. When The Rat King plans to make Irma his first subject, the Turtles and Splinter fight Rat King while April tries to free the captive humans. Michelangelo throws Ice Cream Kitty at Rat King breaking his control over Splinter. While Splinter faces The Rat King, the Turtles face the giant rats. Splinter engages Rat King further underground where he knocks Aristotle off of Rat King's shoulder and then kicks Rat King into the pit. In "Mazes & Mutants," there is a skeleton (or more) that has decaying looking teeth and messy hair which resembles the Rat King's skeleton in Sir Malachi's illusions.
- Aristotle - The Rat King's pet white rat. At the end of "Of Rats and Men," Splinter manages to knock him off of Rat King's shoulder as the rat falls into a chasm. It is unknown if he survived, but it is likely (depending on how high he was), since a rat can fall as far as 50 feet and land uninjured. He was named after the Greek philosopher Aristotle.
- Caligula - A giant rat who serves as Rat King's mode of transportation. He is named after the historical Roman Emperor Caligula.
- Claudius, Nero, and Commodus - The other three giant rats that are named by Rat King. They are named after Roman Emperors Claudius, Nero, and Commodus.
- Rat Man Freak (voiced by Jason Biggs) - A humanoid mutant rat who just appears in "Of Rats and Men." When the Rat King is planning to turn the humans into rat people with his Mutagenic Growth Serum, Aristotle tells him that the serum's not perfected. Then, both the Rat King and Aristotle witnesses the man he tests the serum on mutates into a hideous, disabled monstrosity. His only line was "Cheese! Please give me CHEESE!" His name is not mentioned in the show, but the name comes from the credits.
- Justin - When Karai pushed a button on the machine at the World Wide Genome Project, it caused a variety of animal DNA samples (examples being the DNA of a jellyfish, an isopoda, an octopus, a cobra, and a cat) gathered by the Kraang to dump into the machine's mutagen container and mix together. This ends up forming a composite monster that Mikey calls Justin. It has octopus tentacles for legs, a snake-like neck hooded by piscine fins, a vertical mouth filled with teeth and fangs, a cat-like upper lip, an isopod shell, jellyfish-shaped eyes, and a forked cobra-like tongue. After Karai leaves, Justin attacks the Kraang until only the Turtles are left, but Leo manages to use his katanas as a conductor of electricity to defeat it. In "Metalhead Rewired," Justin is among the mutants captured by the Kraang in order for them to control them. It is seen briefly with Spyroach when he escapes his chamber. He is shot down by a Kraangdroid as he falls several feet, but he managed to survive and escape. With help from Metalhead, the Turtles free the captive mutants and they escape through the portal. In "Meet Mondo Gecko," his silhouette is seen before the start of Fishface's race against Michelangelo, Casey Jones, and Mondo Gecko.
- Spy-Roach / Cockroach Terminator - A cockroach that was trained by Donnie in to spy on the Kraang with special micro-equipment in "Cockroach Terminator," where Raph's fear of cockroaches is revealed. An accident on Donnie's part that happens while it was spying on the Kraang causes Spy-Roach to fall into a vat of mutagen and mutate into an 8 ft. humanoid mutant cockroach with the micro-equipment melted onto its skin (dubbed "Cockroach Terminator" in the toyline). After escaping from the Kraang base, Cockroach Terminator runs into the Turtles and attacks them. Raph is able to use the Shellraiser's cannon to knock it out, yet Cockroach Terminator manages to sneak away behind the Turtles's back. When the Turtles thwart the Kraang's robbery of the special lens, Cockroach Terminator catches up to the group and defeats the Kraang. Then it attacks Raph until Leo saves him. The Turtles use bug spray in order to get Cockroach Terminator out into the street where it gets hit by a truck and collides into the wall. Yet it survives and goes after them. The turtles discover that Cockroach Terminator is targeting Raph, desiring retribution after he attempted to squash it with his Sai prior to its mutation. It chases him until it gets caught in the wet cement, but Cockroach Terminator molts its skin and emerges in a second form which it can now fly. It then chases after Raph while the Turtles are trying to get to the Kraang. When Cockroach Terminator grabs Mikey to force Raph out of hiding, Raph ends up having to overcome his fear to rescue Mikey, piloting his vehicle to lure Cockroach Terminator away so that the other Turtles can stop the Kraang. Raph's fight with it ends up disrupting the Kraang's laser drill. Raph then turns the laser drill on Cockroach Terminator, blasting it apart. Although a new Cockroach Terminator starts to form from one of the fragments of the old Cockroach Terminator or it could be the head of the original Cockroach Terminator that has signs of life. In "Fungus Humungous," he appears as a hallucination (as a larger version of his normal form) as Raph's fear, which are, of course, cockroaches. In "Metalhead Rewired," the real Cockroach Terminator is among the mutants captured by the Kraang in order for them to control them. It is seen briefly with Justin as they both escape their chambers, and then, in its final form, flies out during its escape. With help from Metalhead, the Turtles free the captive mutants and escape through the portal. In "Meet Mondo Gecko," the silhouette of Cockroach Terminator's first form is seen during Fishface's race against Michelangelo, Casey Jones, and Mondo Gecko.
- Parasitica Wasp - A giant mutant parasitoid wasp that hypnotizes the Turtles into protecting its egg by stinging them (the hypnotized victims infect their enemies by biting them). They nearly possessed the Turtles until they were broken free by Mikey and destroyed by the Turtles. Also, it showed that when the wasp stung Leo, it died after having lost its stinger. In real life, wasps do not die after stinging their enemies and therefore they do not lose their stingers since they're not barbed. In "Metalhead Rewired," at least two Parasitica Wasps are among the mutants captured by Kraang in order for them to control them. The first one is seen with a Squirrelanoid, Kirby Bat and Cockroach Terminator when they discover that Metalhead has opened their cells and the portal. Another wasp is seen shortly with a Squirrelanoid and Pete as it flies to the portal. The other wasp is not able to escape as it got knocked out of the air when the portal closes and crashes on the ground. With help from Metalhead, the Turtles free the captive mutants and they escape through the portal.
- Newtralizer (voiced by Danny Trejo) - A tall mutant fire-belly newt in a weapon-upgraded suit of high-tech armor with a huge mouth used to eat the Kraang that was the result of one of the Kraang's experiments with mutagen where he was considered dangerous to them. He first appears in "Operation: Breakout," where he is accidentally released by Donnie from a Kraang detention cell during the second attempt to rescue Kirby O'Neil. Mikey drives a car on top of him, crushing him and allowing them to escape. Newtralizer is shown to have survived after the Turtles leave. In "Metalhead Rewired," Newtralizer is among one of the mutants captured by the Kraang in order for them to control them. He is seen briefly in a background when Slash punches one of the Kraangdroids as Newtralizer, Rockwell, and a Squirrelanoid escape their chambers. He also doesn't have its gear, though he may have reclaimed it before heading to the portal. With help from Metalhead, the Turtles free the captive mutants and they escape through the portal. In "Newtralized," Newtralizer frees Slash from the Kraang and works with him to stop the Kraang's plots and steal some plutonium for their teleporter devices. It is shown that a part of Newtralizer's armor had a program that enabled him to speak human language. When it comes to Newtralizer's collaboration with Slash, it is shown that Newtralizer doesn't care for the humans when it comes to stopping the Kraang. During a fight with the Kraang at the docks, Newtralizer hijacks the Kraang Walker and uses it to attack the Kraang while planning to attack the city, so Raph and Casey Jones work with Slash to stop it. After the Kraang Walker is destroyed, Newtralizer is defeated. The final scene of the episode shows that Newtralizer survives the Kraang Walker's destruction.
- Squirrelanoids - A group of 9 ft. humanoid mutant eastern gray squirrels with red skeleton-like skin, glowing green eyes and mouths and retractable tongues with a secondary head (similar to the Xenomorph from the Alien franchise) that are the results of an eastern gray squirrel drinking from one of the mutagen canisters that fell from the Kraang's stealth-ship during the Kraang's fight with the Turtles in "The Mutation Situation". In "Invasion of the Squirrelanoids," the Turtles find the mutated squirrel and bring it back to the lair where it begins to multiply and mutate. When the Turtles are being overwhelmed by the Squirrelanoids, Splinter arrives and fends them off, allowing them to escape into the tunnels. The Turtles end up going after them to keep them from reaching the surface and causing havoc. Using some popcorn and his knowledge of comic books, Mikey baits the Squirrelanoids into a grain pipe and flushes them into the septic tanks until Donnie can come up with a retro-mutagen to use on them. However, one of the Squirrelanoids manages to escape and attacks a sewer worker who finds the bag of popcorn. In "Fungus Humungous," it appears as a hallucination as Mikey's worst fear after he is sprayed by one of the mushroom's spawns. In "Metalhead Rewired," at least 3 Squirrelanoids are among the mutants captured by Kraang in order for them to control them. One is first seen with a Parasitic Wasp, Kirby Bat and Cockroach Terminator when they discover Metalhead opening their cells. The second one is seen with Dr. Rockwell and the Newtralizer when Slash punches one of the Kraangdroids. The other is seen with a Parasitic Wasp and Pete before making its way to the portal. One of the Squirrelanoids is seen again in a background when Dr. Rockwell beats up one of the Kraangdroids. With help from Metalhead, the Turtles free the captive mutants and they escape through the portal. In "Meet Mondo Gecko," the silhouette of two Squirrelanoids are seen before Fishface's race against Michelangelo, Casey Jones, and Mondo Gecko.
- April Derp (voiced by Mae Whitman) - A reject clone of April O'Neil who only appears in "The Kraang Conspiracy". Unlike most of the clones, she is very large, her right leg and left arm are terribly deformed, a large mouth grows on her back, and a small head on the side of her left eye that resembles the real April. The Kraang sends her to attack the Turtles, but she is killed by the real April's psychic powers.
- Fungus Humungous (voiced by Fred Tatasciore) - A humongous one-eyed mutant mushroom that can grow smaller mushroom spawns and release spores that cause people to see their worst fears. It first appears in "Fungus Humungous," where it is first encountered by a sewer worker who runs by April and Casey ranting about a monstrous squirrel. When April is exposed to the spores, she sees her worst fear of bats including a vision of her mutated dad. The Turtles come with Casey to find April, but when Casey is exposed to the spores, he experiences his fears of being overwhelmed by a swarm of rats. When the Turtles find April, one of Fungus Humungous's mushroom spawns attacks where Raph is exposed to the spores, causing him to see Leo as Spyroach. The Turtles find a lair filled with mushroom spawns causing Leo, Donnie, and Mikey to fight them. Mikey gets exposed to the spores and experiences his fear of the Squirrelanoids. Donnie gets exposed as well, causing him to experience his fear of April hating him. Leo then gets exposed, causing him to experience the fear of losing his team. Leo then falls into the Fungus Humungous's lair, where he finds that the mutagen is responsible for its creation. As Fungus Humungous spreads its spawns, Mikey fights through them while facing his fears. Leo faces his fears and discovers that Fungus Humungous can't stand sunlight. Once Leo lets in a lot of sunlight through the hole in the ceiling, he uses it to defeat Fungus Humungous and neutralize the spores on the others. A twist ending reveales that one of Fungus Humungous' spawns had survived when Mikey finds it on his pizza.
- Antonio / Pizza Face (voiced by John DiMaggio) - Antonio was an Italian pizza chef who ran Antonio's Pizza until he ingested mutagen thinking that it would be a good pizza topping. As a result of this, he mutated into a big mutant blob of pepperoni and mushroom pizza with arms, a gooey mouth, a nose made of mushroom, eyes made of pepperoni and control over different pizzas that come to life by attaching themselves to their victims in a zombie-like state that Mikey dubs "Pizza Face". He first appears in "Pizza Face," where Mikey goes to Antonio's Pizza to get his money back and finds the other victims of Pizza Face as he is attacked by them. Upon returning to the lair, Mikey finds that his fellow Turtles and Splinter have become affected as Mikey fights off Pizza Face's pizzas. Mikey ends up interrogating one of these pizzas to find out who he works for. The pizza ends up telling Mikey about his origin and plans to feed off them. After putting the pizza into the freezer with Ice Cream Kitty, Mikey infiltrates Antonio's Pizza restaurant where Pizza Face (who likes the name that Mikey called his appearance as) is starting to make the humans into calzones for him to feed off of. Mikey confronts him and fights the pizza-controlled Turtles until he ends up trapped in Pizza Face's cheese. Upon eating his way out of the cheese, Mikey fights his way past Pizza Face's victims where he ends up swallowed up by Pizza Face only to eat himself out. Mikey threatens Pizza Face to free his victims or else, and Pizza Face does what Mikey does as every one he brainwashed is freed. Even though it seemed like a nightmare to Mikey, it turns out that Pizza Face's slice has survived and is hiding out in one of the pizza boxes. In "Meet Mondo Gecko," Pizza Face's slice is seen during Fishface's race against Michelangelo, Casey Jones, and Mondo Gecko.
- Ho Chan (voiced by James Hong) - A powerful martial artist during China's Shang Dynasty whose martial arts powers were so incredible that they were mistaken for sorcery. He was cursed without flesh and trapped in an ancient dagger which is stolen by the Purple Dragons (who were stealing artifacts for Steranko) in "A Chinatown Ghost Story". The Purple Dragons release him and he gives them the powers of lightning, thunder and wind, making them his loyal servants and giving him control over their minds. Ho Chan orders the Dragons to go after April O'Neil, since only with her powers could he be mortal again. Irma is also captured where Ho Chan claims that Irma has some type of power in her (Ho Chan was unaware that Irma was actually Kraang Subprime in disguise). Later, Ho Chan takes the Purple Dragons' powers since they were "losers" and gives it to Leo, Raph and Mikey, turning them against Casey and Donnie. April is able to defeat him by stabbing him with the dagger, trapping him inside once again. As Donnie sends the Mystic Dagger to the depths of the ocean, Ho Chan vows to return. Ho Chan is a homage to James Hong's character Lo Pan from Big Trouble in Little China.
- Creep - A regenerating 8 ft. mutant swamp monster made of mud and moss with the clothes of a sun-beaten scarecrow, superhuman strength and vines used as whips growing out of his body that is the result of Leo vomiting a medicine that had mutagen in it onto the shores of a creek in "Within the Woods". Following this, he stalks the Turtles, April, and Casey near the O'Neil Farmhouse, targeting Raph first. He then ambushes Donnie and Mikey near a shack containing the bottle of the mutagen medicine. During the fight that follows, the medicine causes Raph to mutate into a plant mutant. As soon as Creep finds and attacks Casey and April, who try their best to take him down, he ends up taking Casey's mask. Upon seeing April get abducted, Leo traces Creep to his shack and fights him and fails to defeat him. After Leo walks back to the shack with the group, they use the mutagen medicine bottle and play keep away with Creep until the bottle is destroyed by Leo and Creep is chained by April and Casey. Donnie then uses an I.V. vacuum to drain the mutagen out of him in order to restore Raph to his regular form. The rest of Creep ends up back into his goo-like form which starts to glow in a glass jar as it begins to crack. Creep is intended as an homage to the horror movie villain Jason Vorhees, mostly to his appearance in Friday the 13th Part 2 and the use of Casey Jones' mask.
- The Finger (voiced by Jesse Ventura) - A hunter and collector wearing a shrunken head around his neck that he refers to as his mother (because it almost looks like that is where his high voice is coming from) whose name is attributed to an extra finger he has on his right hand. He first appears in "A Foot Too Big," where he hunts down Bigfoot and stumbles upon the Turtles as well. After Bigfoot runs into the forest after hearing Leo and Casey making fun of her, she falls into The Finger's trap. When Donnie and Mikey run after her, they are captured by as well. The two Turtles manage to escape and try helping Bigfoot but are overpowered by The Finger's fighting moves. When The Finger is about to kill Bigfoot, he realizes that Bigfoot is a lady (due to April giving her a makeover earlier) which he says he would never harm. After he apologizes to his mother and breaks down in tears, Bigfoot carries him off into the woods.
- Mom Thing (voiced by Renae Jacobs) - A Kraang/human abomination that was a composite of the thoughts and Kraang DNA of April's mother, Mrs. O'Neil. It first appears in "Buried Secrets," where the Turtles, April, and Casey discover a Kraang ship containing the creature's frozen body in Mrs. O'Neil's form in the basement of the O'Neil family house. After she is unfrozen, the creature acts like Mrs. O'Neil is surprised to see her daughter again. However, Mikey has his suspicions about her, which the rest of the guys don't believe. While following her into the woods, Mikey discovers that he is right, and that Mrs. O'Neil is actually a Kraang in disguise. She overpowers him, however, and places him under mind control. After she does the same to Donnie and Leo, Raph finally realizes that Mikey was telling the truth, but April and Casey still don't believe him. It isn't until Mrs. O'Neil (in her human form) forces April to leave with her that she reveals her true identity, turning into a giant spider-like Kraang that Raph dubs "Mom Thing". After attacking the remaining three in the barn and swallowing Raph and Casey, she convinces April to join her. April defeats her by using her psychic powers to blast her apart and turn everyone back to normal. Donnie reveals that the Mrs. O'Neil they discovered was only a composite of her thoughts and Kraang DNA, assuming that the real Mrs. O'Neil is still dead. April is convinced however that her mother is still alive somewhere. In a twist ending, the mutagen that Mom Thing spills plays a part in the origin of the Punk Frogs. Mom Thing is intended as an homage to John Carpenter's The Thing (which in turn is based on the novella Who Goes There?).
- Dream Beavers - A family of over-sized humanoid North American beavers from the Dream Dimension with dream-infiltrating abilities who sought to take over Earth after they were brought to the dreams of Earth's people when a physicist named Bernie was working on dimension-traveling machine called the Dream Plug. He kept this machine ever since in his Latin book to prevent penetration of the Beavers into the earthly dimension, and has been keeping himself awake for forty years in order to prevent them from getting into his dreams. They first appear in "In Dreams," where they infiltrate the dreams of the Turtles and bring their nightmares to life in order to drain their life-force. April uses her powers to enter their dreams in order to get them to wake up. When the Turtles realize that they are in a dream, the Dream Beavers come together to attack them. Upon learning about them from Bernie, Casey destroys the Dream Plug which not only wakes the Turtles but also frees the Dream Beavers who convert into a smaller size and return to their dimension as Bernie finally falls asleep. The Dream Beavers are a loose homage to horror movie villain Freddy Kreuger (who was originally portrayed by Robert Englund who voiced two of the beavers).
- Dire Beaver (voiced by Robert Englund) - The purple-furred leader of the Dream Beavers with glowing red eyes and a bomb symbol tattooed on his stomach who infiltrates Leo's dream.
- Dark Beaver (voiced by John Kassir) - A red-furred member of the Dream Beavers with glowing red eyes and a flaming skull symbol tattooed on his stomach who infiltrates Donnie's dream.
- Dread Beaver (voiced by Robert Englund) - An orange-furred member of the Dream Beavers with glowing red eyes and a crying cracked skull symbol tattooed on his stomach who infiltrates Raph's dream.
- Dave Beaver (voiced by John Kassir) - A blue and pink-furred member of the Dream Beavers with blue eyes and a rainbow-and-starred heart symbol tattooed on his stomach who infiltrates Mikey's dream than the Turtles shared dreams. Dave is the unintelligent member of the group.
- Speed Demon (voiced by Steven Blum) - A mutant purple muscle car entity capable of turning whoever is driving it into its mutant host with the need for speed that is the result of a car running over a spilled mutagen supply that Rasputin the Mad Frog looses during the Punk Frog's fight with the Turtles in "The Croaking". In "Race with the Demon," it pursues Donnie, April, and Casey in their station wagon and tries to run them off the road. News of the Demon Racer's vehicle causing trouble on the road reaches the local news. In order to get even with the Speed Demon, Casey and Donnie construct a racing vehicle to compete with it. When Casey later encounters Speed Demon's vehicle, he finds out that Speed Demon is actually a mutant. Speed Demon then plans to run an old lady and her vehicle off the road, but Casey repels him just as the rest of the Turtles and April catch up. Mikey finds mutagen that leaked from Speed Demon onto the road as Donnie claims a sample of it. While piloting the new car (which is made from parts of Kraang technology) with Dr. Cluckingsworth, Casey tries to take down Speed Demon by using a smokescreen to slow it down. Donnie then removes the driver (who returns to normal) from the car, but is too late to learn that the car is the actual mutant as Speed Demon possesses him. In order to get Donnie out of Speed Demon, Casey is challenged to a race to Dead Man's Curb. With help from Dr. Cluckingsworth, Casey frees Donnie from Speed Demon as it starts attacking them, only to get knocked off a cliff when the other Turtles and April arrive in the party wagon. As Speed Demon falls into the forest below and explodes, it vows to return. In "Eyes of the Chimera," Speed Demon's explosion causes some of the mutagen inside it to play a part in creating the Chimera.
- Chimera - An 11 ft. mutant falcon/fish/earthworm hybrid that is the result of a falcon getting soaked with mutagen from the exploded Speed Demon after it catches and consumes a fish with an earthworm in its mouth. The next day, in "Eyes of the Chimera," it attacks the O'Neil Family summer house and fights the Turtles and Casey Jones. When Donnie mentions it to be a Chimera, Mikey joked that it was a "Turducken." The Chimera manages to make off with Raph, Donnie, Mikey, and Casey. Due to the side effects of the neuro-transmitter, April is able see through the Chimera's eyes and suspects that the Chimera would eat them. But she and Leo first had to overcome their disabilities in order to get to Talbot Peak and rescue them. Once at the peak, the Chimera traps Raph, Donnie, Mikey, and Casey in a hole that appears to be a geyser. When Leo and April arrive near the geyser hole, April sees the Chimera arriving as it snatches them and manages to get to the Chimera's gills in order to steer it as Leo hits it on the head hard enough for it to get stuck in the hole which starts to cause Talbot Peak to have an rockslide. The Chimera manages to get out of the burial as it prepares to eat a squirrel. Chimera bares a striking resemblance to the "bird the size of a battleship" from the 1957 B-movie The Giant Claw.
- Tang Shen - The wife of Hamato Yoshi and the mother of Hamato Miwa, who died 15 years ago when Splinter's adoptive brother and rival suitor, Oroku Saki, broke into the Hamato Clan monastery and burned it to the ground while spiriting away Karai. She only appears in flashbacks since her death.
- Mrs. O'Neil (voiced by Renae Jacobs) - The mother of April and the wife of Kirby. In "Karai's Vendetta," April first mentions her, distracting Karai with the fact that April has lost her mother as well as she manages kick her down a flight of subway stairs and escape. Mrs. O'Neil first appears for the first time in "The Kraang Conspiracy" in an old family photo as Jack Kurtzman reveals the extradimensional Kraang wanted for yet unexplained reasons a suitable human host for their plans of conquest for the Earth and finally found it in Mrs. O'Neil, so they kidnapped her before April was born and subjected her to experiments in which her human DNA was mixed with the their genetic material. As a result, April was born half Kraang, half human. In "Buried Secrets," the turtles find April's long-lost mother frozen in a Kraang ship buried under the O'Neil farmhouse, but the "Mrs. O'Neil" they find turns out to be a Kraang/human hybrid with Mrs. O'Neil's memories that Raph dubs "Mom Thing". After the Mom Thing is destroyed, April believes that her real mother is still alive somewhere.
- Metalhead - A durable 4 ft. turtle robot armed with a variety weapons at its disposal such as a flamethrower and a laser cannon that is built by Donnie from salvaged Kraang technology. It first appears in "Metalhead," where it is ironically used by Donnie to thwart the Kraang's plot in dumping mutagen in the city's water supply. Unfortunately for Donnie, a Kraang crawls onto Metalhead's head seizes control of it before attacking the Turtles. It is defeated when Donnie arrives and knocks down a column onto his creation and thrusts his bo-staff into Metalhead's chest, shutting it down and breaking the Kraang's control over it. In "Metalhead Rewired," it sacrifices itself to save the Turtles and the mutants from the Kraang. The only thing that remains of Metalhead is its head, although Donnie may build another Metalhead one day in the future. Metalhead's severed head is seen on the shelf in the background of the lab in some episodes.
- Carlos Chiang O'Brien Gambe (voiced by Jim Meskimen) - A local TV news reporter who reports on the different happenings in Manhattan.
- Mr. Murakami (voiced by Sab Shimono) - A blind, but skillful Japanese chef who runs a noodle shop. He becomes a friend to the Turtles after they save him from an extortion attempt by the Purple Dragons. Despite being blind, he knows what the Turtles are, but isn't afraid of them. Murakami rewards the Turtles with a dish called "Pizza Gyoza" (a type of Japanese-style dumpling that is stuffed with pizza ingredients) which the Turtles love. April and The Turtles address Mr. Murakami as "Murakami-san."
- Joan Grody (voiced by Kari Wahlgren) - The hostess of a TV show called "Grody to the Max." In "The Noxious Avenger," Joan Grody later reports on the heroic antics of Muckman and nearly sees the Turtles. By Muckman's latest appearance, he told Joan Grody that the "Turtles" were actually humans dressed as turtles like how the Pulverizes had operated.
- 80's Teenage Mutant Ninja Turtles - While in a room full of portals, Donatello, April O'Neil, and Casey Jones look into a portal where they see their 80's counterparts. In the final scene, the 80's Teenage Mutant Ninja Turtles see a Kraathatrogon emerge in Manhattan and engage it. The 80's Turtles are also seen in a flashback of "The Wrath of Tiger Claw," where they encounter Tiger Claw in their own dimension when he got out of the Kraathatrogon.
- 80's Leonardo (voiced by Cam Clarke) - The 80's counterpart of Leonardo.
- 80's Donatello (voiced by Barry Gordon) - The 80's counterpart of Donatello. An error in the credits shows 80's Donatello is credited as Townsend Coleman.
- 80's Raphael (voiced by Rob Paulsen) - The 80's counterpart of Raphael.
- 80's Michelangelo (voiced by Townsend Coleman) - The 80's counterpart of Michelangelo. An error in the credits shows 80's Michelangelo is credited as Barry Gordon. He also made an appearance in "Never Say Xever" when Michelangelo imagined himself having his 80's counterpart's face when he thinks about getting his first tattoo.
- Martin Milton / Sir Malachi (voiced by Paul Reubens) - Martin Milton was a boy who played LARP game "Mazes & Mutants" so much that he played it for every hour of every day. One day, he was exposed to a falling mutagen canister while he was feeding a flock of house sparrows some bread that was in his hands. As a result of this, Martin mutates into a dwarfish mutant house sparrow in a medieval-style hood and tunic with a left peg leg and carrying a staff with an egg-shaped decoration on top used to perform magic and illusions that dubs himself "Sir Malachi," referring himself as a "sparrow wizard" and doing solo LARP in the sewers. He first appears in "Mazes and Mutants," where he uses his magic to send the Turtles into the "Mazes & Mutants" game where he has them go through the quest in order to defeat a dragon and free Princess April. The Turtles go through Sir Malachi's game where the first riddle involves fighting the Monkey Goblins that resemble Dr. Tyler Rockwell's mutant form. When Raph challenges Sir Malachi, he turns Raph's head into a turkey's head. The next riddle Sir Malachi gives involves the Turtles evading a rolling fireball. When the Turtles find April and end up fighting the dragon, which resembles Leatherhead, Sir Malachi arrives upon the dragon's defeat where he wants the Turtles to play his game until his heart is content. Leo states that Sir Malachi is a mutant who created the maze in their mind. Raph throws Mikey's Ring of Awesomeness towards Sir Malachi. Upon the Turtles not believing in Sir Malachi's illusion, the spell is broken and the Turtles learn Sir Malachi's origin. After being promised not to play the "Mazes & Mutants" his way again, Sir Malachi leaves with the illusions of Leatherhead and the Monkey Goblins right behind him. The creators of this show have said that Malachi's character was inspired by the role-playing games that they all enjoy and they very much wanted a "wizard" character.
- Long-Tongue Worms - Small alien worms from Dimension X that all appear harmless unlike most creatures from Dimension X. They appear in "Into Dimension X" where Mikey demonstrates that they use these worms as lassos, and the green liquid that comes out of their rear end is edible. He then takes one with him back to Earth. In "Battle for New York", Mikey in his "savage" outfit uses a lone long-tongue worm to fight a Kraathatrogon.
- Earth Protection Force - A secret black-ops unit created to handle extraterrestrial threats. They first appear in "The Invasion" where they take on Kraang Prime to protect New York City. In "Return to New York," they are put under the Kraang's control and forces the Turtles, April and Casey not come to New York. When April notices a Kraang Mind Control Device on one of the soldiers and bets they all have them, Casey drives to the city with all his might as the brainwashed force start shooting, failing to destroy them.
- April's Great-Grandfather - The unnamed great-grandfather of April, who built the O'Neil farm many years ago. Unknowingly to him, he didn't realize that a Kraang ship (which crashed on Earth) was under the house. One day, he discovered the Kraang ship and accidentally awoke several Kraang before they experimented on him.
- Deer Spirit - A spirit of nature residing in the woods of North Hampton with two forms: a normal white-tailed deer and a humanoid white-tailed deer. It first appears in "Vision Quest" in its humanoid form, although Leo is also able to see it as the ordinary deer buck that he had tried to hunt. The Deer Spirit allows Master Splinter to contact the Turtles through its presence via a bonfire and puts the Turtles through a rigorous test on the spectral plane to sharpen their spiritual strength and overcome their fear of the Foot Clan leading to their preparedness for their return to the city. The Deer Spirit is possibly a reference to the Trickster of Native American legend.
TV show characters
The following characters appear in the TV shows that are watched by the Teenage Mutant Ninja Turtles:
Space Heroes characters
Space Heroes is fictional animated science fiction TV series that is Leonardo's favorite show. It is a parody of Star Trek: The Animated Series.
- Captain Ryan (voiced by Brian Bloom) - The main hero and leader of a spaceship crew in "Space Heroes." He resembles Captain James T. Kirk.
- Crankshaw (voiced by Scott Menville) - A young ensign who Captain Ryan slaps every time he panics.
- Dr. Mindstrong (voiced by Ben Cross) - An alien scientist.
- Commander Grundch (voiced by Nolan North) - The second-in-command of Captain Ryan.
- Rodriguez (voiced by Greg Cipes) - A soldier chosen by Captain Ryan for a suicide land mission.
- "That Other Guy" (voiced by Rob Paulsen) - A green-skinned human-like alien who was chosen by Captain Ryan for a suicide land mission. He resembles an Andorian from the Star Trek franchise.
- Trumplets - Small, cute and furry, yet annoying creatures. They are a parody of the Tribbles from Star Trek.
- Celestial (voiced by Anna Graves) - A minor character who tried to seduce Captain Ryan into giving her the secret codes only for Ryan to disintegrate her. Captain Ryan keeps her boots as a memento.
- Hypnotica - An alien that brainwashed Captain Ryan into thinking it was a beautiful woman.
- Cortexicons - A race of strange mind-controlling aliens. One of them took control of Dr. Mindstrong in one episode (a cryptic prediction of Metalhead getting possessed by the Kraang).
- Digesters - A race of large, orange blob-like creatures (although one was shown) that attacked a landing party sent by Ryan. It is later heard eating the trio and belches. The digester resembles Cloggy Colon Creature from Super Robot Monkey Team Hyperforce Go!
Super Robo Mecha Force Five characters
Super Robo Mecha Force Five is a fictional anime show that was discovered by Michelangelo in "Mutagen Man Unleashed" and has very bad acting. It is also called SRMFF! for short. The series is a pastiche of the animated series Voltron and includes elements of the anime Mazinger Z, the American/Japanese animated television series Super Robot Monkey Team Hyperforce Go, and the Power Rangers franchise (which actually crossed over with Ninja Turtles: The Next Mutation in an episode of Power Rangers in Space). Unlike Space Heroes, all four Turtles like the show.
- Captain Dash Coolstar (voiced by Brian Bloom) - The leader of the Super Robo Mecha Force Five and main character of the "Super Robot Mecha Force Five" anime who controls the torso of Mighty Super Robo Mecha. He represents Leonardo.
- Dr. Blip (voiced by Scott Menville) - The scientist of the team who controls the right leg. Similar to Crankshaw, Dr. Blip gets slapped by Captain Dash Coolstar every time he panics. He represents Donatello.
- Squeakums - An alien monkey and animal sidekick of the team who pilots the right arm. He represents Michelangelo.
- Lunk (voiced by Nolan North) - The hot-tempered member who controls the left arm. He represents Raphael.
- Princess (voiced by Mae Whitman) - The female member who pilots the left leg. She is the princess of an entire planet and Dr. Blip has a crush on her. She represents April.
- General Unsura (voiced by Kevin Michael Richardson) - A villain who once took control of Mighty Super Robo Mecha. He resembles Baron Ashura from Mazinger Z (due to his face) and Count Brocken from Mazinger (as his actual face is separated from his body).
- Mind Master (voiced by Nolan North) - A villain who once tried to fill Coolstar's mind with madness.
- Skele-Lord (voiced by Josh Peck) - A skeleton-like villain who was defeated by SRMFF when they stomped on him. He later came back with a giant mecha of his own. He is a parody of the Skeleton King from Super Robot Monkey Team Hyperforce Go! and Skeletor from the Masters of the Universe franchise.
- Cyberoid X (voiced by Brian Bloom) - A minor villain.
- Kill Beast Bots - Robotic yellow beasts from the planet Sevenorth.
- Giant Space Squid - An alien squid that was destroyed by SRMFF.
- Hydra Beast - A three-headed dragon-like alien. It is a parody of King Ghidorah from the Godzilla series.
Crognard the Barbarian characters
- Crognard the Barbarian (voiced by Brian Bloom) - The main character who is a spoof of Thundarr and somewhat resembles He-Man. He can get stronger by quoting "By the Power of Lobnarr, I Have the Energy."
- Wizardess (voiced by Mae Whitman) - The magic-wielding ally of Crognar. She is a spoof of Princess Ariel.
- Graah (voiced by Nolan North) - The monstrous ally of Crognar. He is a spoof of Ookla the Mok, but he resembles the monster Spooky Space Kook from Scooby-Doo, Where Are You!.
- Spooch (voiced by Scott Menville) - A small floating fish-like creature who is Crognard's ally. Unlike the other three main characters, he does not appear to resemble a character from Thundarr the Barbarian, though he was probably modeled after Slimer from the Ghostbusters franchise. He also appears to be cowardly and likes to repeat his own name much like Snarf from ThunderCats.
- Mounts - Various creatures that are used as mounts for the heroes.
- Go-lek - Crognard's pet lizard steed. It appears to be based on Megalania.
- Horses - The heroes' first mounts that are parodies of the horses from Thundarr. They reappear in "Return to New York".
- Reptilian Steeds - Three dinosaur-like creatures that the heroes use to chase Muurg. They resemble Parasaurolophus.
- Slug People - A race of slug-like creatures who tried to show their kindness to the heroes. Instead, they were beaten up when Wizardess had a bad vibe about them.
- "Slug People Leader" (voiced by Nolan North) - The supposed leader of the Slug People who also tries to show kindness to the heroes, but is brutally beaten up by Crognard.
- Giant Mountain Demon - A giant mountain-sized demon that swallowed Wizardess, but is defeated by Crognard.
- Muurg (voiced by Brian Bloom) - An evil horned centaur that stole the Mystic Jewel of Koweewah. He is pursued by Crognard's group and is defeated by Crognard after Wizardess froze Muurg's feet.
- Megalord Zarrik (voiced by Jim Meskimen) - A villain who is able to change faces. He uses demonic soldiers to guard the entrance to the Fortress of the Ragnaroid. He cheerfully taunts Crognard, telling him that he will never get through the Gates of Eternal Stagnation. He appears to be modeled after Thundarr villain Gemini (who is able to change between his two faces), but he is also similar to Man-E-Faces from the Masters of the Universe franchise.
- Grom and Grum (voiced by Fred Tatasciore and J.B. Smoove) - A two-headed ogre with a blue right side named Grum and a purple left side named Grom that share the same body and are considered brothers. Grom and Grum were known for terrorizing the village of Magooloorooroo. They fought Crognard's group until they are beaten by them. Grom and Grum's color scheme is similar to Two-Bad from the Masters of the Universe franchise.
- Gorrick Army - An army of muscular orc-like creatures that carrying various weapons. Crognard yells at the Gorrick for blaming his enormous pecs. When Wizardess told him that the Gorrick army outnumbers them 1,000 to 1 and saying they're doomed, Crognard doesn't give up easily as he jumps into battle, but a stabbing sound can be heard.
- Malfidor (voiced by Tom Kenny) - A mind-controlling wizard who took control of Wizardess, Graah, and Spooch. He finds himself unable to take over Crognard's mind as Crognard breaks Malfidor's mind-control. Wizardess, Graah, and Spooch then beat up Malfidor.
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- Exclusive: Teenage Mutant Ninja Turtles Guest Cast Includes Roseanne Barr - Today's News: Our Take | TVGuide.com