A team of anthropomorphic freshwater turtles who are kept a secret from the world by usually going to the surface only in the night time.
Leonardo/"Leo" (voiced by Jason Biggs) - 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 (a parody of the 1970s Star Trek animated series) which annoys his brothers to no end. In this incarnation, his skin seems darker than his brothers'. Leo drives the Shellraiser.
Raphael/"Raph" (voiced by Sean Astin) - Raphael often lets his impulsiveness get in the way of rational thinking. 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. This incarnation of Raphael is depicted with a lightning bolt-shaped crack in his upper left plastron. In "Cockroach Terminator," it was revealed that Raphael was afraid of cockroaches until he managed to defeat the mutant cockroach Spyroach. Raph is in charge of the Shellraiser's weapons systems.
Michelangelo/"Mikey" (voiced by Greg Cipes) - Michelangelo is a lover of video games, skateboarding, pranks and pizza. He 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. Despite possessing a childlike innocence, he always brings his best game to a fight. Mikey is in charge of navigating the Shellraiser.
Hamato Yoshi/Splinter (voiced by Hoon Lee) - Splinter is the turtles' rat sensei. Ninjutsu master Hamato Yoshi (Splinter) once lived in Japan, where he was good friends with another ninja clan leader, Oroku Saki (Shredder). The two men fell in love with the same woman, Tang Shen, who ultimately chose Splinter over Shredder. As a result, the men's friendship ended. Splinter and Tang Shen married and had a daughter Miwa. Shredder, still bitter over the loss, sought to finish Splinter. Their battle resulted in a fire that killed Tang Shen and Miwa, and burned down Splinter's home. After moving to New York City, Splinter had just purchased four young pet turtles when he was bumped by a strange man in the street. According to Splinter, "something felt 'off'" about the man, so Splinter followed him and witnessed a suspicious conversation between two humanoid Kraang robots. The Kraang spot Splinter and attack him to keep him quiet. During the fight, a canister the Kraang were carrying breaks open and splashes Splinter and his turtles with an alien chemical. Splinter transforms into a humanoid rat after having come into contact with a rat when he entered the alley and it ran into him. Realizing he could no longer live a normal life on the surface, Splinter retreats to the sewers where he raises his pets as his sons and teaches 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 "Showdown" Pt. 2, Splinter finds out from Shredder that his daughter Miwa is still alive. When he was 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.
April O'Neil (voiced by Mae Whitman) - April O'Neil is the 16 year-old daughter of Dr. Kirby O'Neil. April 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 steel 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 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," Karai tries to hunt April down again. April's friendship with the Turtles is rekindled after they rescue her from Karai.
Kirby O'Neil (voiced by Keith Silverstein) - Kirby O'Neil is a scientist and the father of April O'Neil. He and April were captured by the Kraang. Although April was rescued by the Turtles, the Kraang made 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 were unable to rescue Kirby as he was recaptured, buying the Turtles time to escape. In "TCRI", it is revealed that Kirby O'Neil is a psychologist and that 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 has been 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. As a result of falling past a flock of bats, Kirby turns into a mutant bat with a large head, wings on his back, ears shaped like bat wings, and the retaining of his red hair and beard. Kirby's mutated form chases after April and flies off with her. Mikey comes up with names for Kirby's mutated form like "Kirby Bat" (which is what the action figure of his mutated form is referred to) and "Wingnut", but Donnie tells Mikey not to give him a "monster name". When April awakens on another roof, the mutated Kirby arrives and regurgitates what he would consider food, such as rats and garbage. With Michelangelo dressed up as a butterfly as part of a plan to get Kirby, the turtles use Mikey as bait to trap Kirby in the warehouse by drawing Kirby's mutated form towards them. The Turtles struggle to get through to Kirby'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 Donatello vows to find a way to cure Kirby, he breaks free and ends up flying off. The mutation of Kirby has temporarily put a strain in April's friendship with the Turtles.
Pete (voiced by A.J. Buckley) - Pete is a pigeon that was mutated by the Kraang. Pete learned to talk and befriended Kirby O'Neil who used him to send a message to his daughter. He told the Turtles the location of where Kirby is in exchange for some bread.
Leatherhead (voiced by Peter Lurie) - Leatherhead is an alligator that was originally owned by a young boy until his parents found out and flushed him down the sewer. The Kraang took him to Dimension X, mutated him, and experimented on him. Leatherhead eventually escapes from the Kraang, steals the energy source that powers the portal between the Kraang dimension and Earth, and retreats to the sewers. The Kraang locate and attack Leatherhead, to demand the return of the power cell. The Turtles witness this event and Michelangelo urges his brothers to help intervene. The Turtles protect Leatherhead, restore his health, and keep the power cell from the Kraang. In "TCRI," Leatherhead tells the Ninja Turtles where the Kraang's base is by drawing the shape of the TCRI building. Leatherhead helps the Turtles by attacking the Kraang while the Turtles make their way to the top of TCRI. Leatherhead even helps to fight Traag which ends with Leatherhead dragging Traag back to Dimension X.
The Pulverizer/Timothy/Mutagen Man (voiced by Roger Craig Smith) - Timothy is an ineffective costumed vigilante who calls himself the Pulverizer and models his appearance after the Turtles. In their first encounter with The Pulverizer, The Turtles rescue him from a bungled attempt to stop the Purple Dragons from looting a warehouse. The Pulverizer winds up back at the Turtles' lair after he accidentally gets stuck to the Shellraiser. Taking pity on the would-be hero, Donatello attempts to train The Pulverizer in basic self-defense, but The Pulverizer shows little capacity to learn. In a failed attempt to stop the Kraang from fleeing with their power cell, The Pulverizer winds up in need of help, and Donnie chooses to save him instead of getting the power cell back. The 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 "cannon fodder") and he agrees to gather info on Shredder's plans for the Turtles, and later volunteers to be a test subject for a supply of stolen Kraang Mutagen. During the Turtles' rescue attempt, he attempts to activate the mutagen machine, although he is stopped multiple times by Donatello. However, he was successful on one attempt, causing the mutation to occur. Since he had not come into contact with anything animal or plant-related prior to volunteering, the Pulverizer is transformed into a mutant blob with floating organs and a disintegrating touch (becoming this series' interpretation of Mutagen Man). Timothy is rescued by the Turtles (who worked together to place Timothy in the empty mutagen container) and Donatello vows to find a way to restore Timothy back to normal. In "Mutagen Man Unleashed," Donatello 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 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 manages 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 Mutagen Man with a retro-mutagen prototype. Mutagen Man's frozen body is taken back to the lair as Donatello vows to continue finding a cure for him.
Casey Jones (voiced by Josh Peck) - Casey Jones is a young student at April's School who got held back. He is missing his two front teeth, is usually dressed in black, and almost never goes anywhere without his hockey stick. When April was hired to tutor him for an extra credit assignment when they first met, Casey shows April his courtesy and the two quickly become friends, much to Donatello's jealousy. He shows admirable fighting skills, especially when he helps April fight of an entire Foot Soldier squad which he eventually ends up defeating himself.
Ice Cream Kitty - Ice Cream Kitty is a mutant cat/ice cream hybrid that will appear in season 2. Its body is colored like Neapolitan Ice Cream.
Kurtzen (voiced by Robert Forster) - Kurtzen is a human character coming in season 2. Kurtzen tells the Turtles and April that the Kraang have been attempting to terraform the Earth for thousands of years, but needed a "specific chain of human DNA". Kurtzen was a journalist investigating the disappearance of April’s father, leading to him discovering the Kraang and investigating them on his own. Displaying a book full of notes, Kurtzen insists that the Kraang presence on Earth is “ancient” and actually goes back thousands of years.
Foot Clan - An evil ninja organization led by Shredder.
Oroku Saki/Shredder (voiced by Kevin Michael Richardson) - One of the main villains of the series and leader of the Foot Clan. Once friends in Japan, Oroku Saki (Shredder) and Hamato Yoshi (Splinter) fell in love with the same woman, Tang Shen. Tang Shen ultimately chose Splinter, which made Shredder jealous, which caused their friendship to end. Shredder's jealousy turned to anger and hatred. When Shredder sought to finish Splinter, their battle resulted in a fire that killed Tang Shen and their daughter Miwa, burned down Splinter's home, and disfigured part of Shredder's own face. Years later, Shredder learns that Splinter is alive and in New York after noticing the Hamato clan crest imprinted on a shuriken during a television news report. Seeking to finish his business with Splinter, Shredder and his Foot Clan relocate to New York. The Turtles first encounter Shredder in "The Gauntlet", where he dominated them all in combat. Shredder almost kills Leonardo, but the distraction of the newly mutated Xever and Chris Bradford gave the Turtles the chance to escape. In the same episode, Shredder is shown to have a pet Akita named Hachinko. Shredder is also Karai's father as seen in "New Girl in Town." In "The Alien Agenda", Shredder didn't believe in the Kraang until Karai brought him the robot body of one of the Kraangs. 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. Shredder ends up sending Karai to capture April in order to draw the Turtles to him. In "The Pulverizer Returns," Shredder decides to obtain mutagen so that he can transform some of the Foot Ninjas into mutants just like how Chris Bradford and Xever were mutated. After the Turtles thwarted the plot, the captive Kraang operative tells Shredder that they have a common enemy in the Turtles. In "Showdown" Pt. 1, April's capture leads to Master Splinter confronting Shredder at his base where Shredder sees that Splinter is a humanoid rat as they begin to fight. In "Showdown" Pt. 2, Shredder and Splinter continue their battle. During the course of the battle, Shredder reveals that to complete his revenge he actually took Splinter's daughter Miwa (who was revealed to have survived the fire,) renamed her Karai, and deceived her from infancy to believe that Splinter had been responsible for her mother's death. In "The Mutation Situation," Shredder orders some mutagen from the Kraang. After the mutagen canisters are scattered throughout the city, Shredder plans to build his army on his own. In "Follow the Leader," Shredder leaves for Japan to take care of an urgent matter where he tells Karai not to do any action towards the Turtles while he is away.
Karai/Miwa (voiced by Kelly Hu) - Karai is a rebellious teen member of the Foot Clan and an expert kunoichi. She first appears in a duel with Leonardo, while the other Turtles are out looking for Snakeweed. She is also the daughter of the Shredder. Karai tries to encourage Leonardo to break the rules for a change, daring him to help her steal a sword once owned by swordsman Miyamoto Musashi. When Leonardo's life is threatened by Snakeweed and he asks for her help, Karai throws a knife toward him, (which helps him break free), which Leonardo interprets as an act of friendship but which Raphael considers malicious. She later attacks the Turtles at the Kraang's World Wide Genome Project. Karai pushed 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 escaped with the Kraang robot body and presented it to Shredder as Baxter Stockman gets to work studying the technology. Shredder then 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. Shredder ends up sending 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 Miwa. But Karai reveals she believes Splinter killed her mother Tang Shen, a lie fed to her from birth by Shredder. Upon learning this, Splinter evades Karai's attacks and retreats in sadness. In "Follow the Leader," Karai trains with the Foot Bots until Shredder arrives. Shredder tells Karai not to do any actions towards the Turtles while he is in Japan dealing with an urgent matter. Karai goes against Shredder's orders and decides to test the Robot Foot Soldiers on the Turtles. When Leonardo gets captured, Karai has the Foot Bots attack Leonardo as part of their training at the Bradford Dojo where they managed to defeat them. Upon the other Turtles arriving, Karai has the Foot Bots restrain the Turtles so that she can draw Splinter to her. When the Turtles make a tactical retreat, Karai orders the Foot Bots to pursue them. Karai even engages Leonardo to a sword fight where Leonardo tries to convince her that Splinter did not take the life of her mother.
Chris Bradford/Dogpound/Rahzar (voiced by Clancy Brown) - Chris Bradford is a famous martial artist (who is modeled after Chuck Norris) and secretly also a member of the Foot Clan. Chris Bradford is ordered to New York with Xever to find Splinter. After his first encounter with the Turtles, he befriends Michelangelo on a social mediawebsite in an attempt to entrap the Turtles, going so far as to teach Mikey his secret kata "The Death Dragon", which Bradford 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 Xever are flushed down the sewers. In "The Gauntlet", Bradford and Xever go after the Turtles again and are exposed to mutagen when Chris Bradford stabs the mutagen container part of the bomb on top of the Wolf Hotel which washes him and Xever off the building. As Bradford was previously bitten by Shredder's pet Akita Hachiko, the mutagen transforms him into a spike-backed dog-like mutant with a large left arm, a right arm that is hard as his spikes, heightened senses, and super-strength that Mikey dubs Dogpound. He also has a mustache. 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 goes after Baxter Stockman so that he can make him normal. During the fight at Baxter's lab, Dogpound falls into Baxter's mutagen tank during his fight with Michelangelo and emerges as a near-skeletal werewolf-like mutant that Mikey called "Rahzar" who is stronger and more agile. Mikey tricks Rahzar into attacking the electric system as the sprinklers go off, electrifying Rahzar, Fishface, and Baxter Stockman.
Xever/Fishface (voiced by Christian Lanz) - Xever was a Brazilian street urchin who lived on the streets and survived whatever way he could. He grew up as a successful thief until he was caught by the authorities during one of his burglaries and imprisoned until Shredder freed him (the briefcase that Xever tried to steal belonged to Shredder) and indoctrinated him into the Foot Clan. Shredder orders this ruthless, accomplished fighter to assist Chris Bradford in finding Splinter. He has been paired up with Chris Bradford since Xever is familiar with the criminal underworld of Manhattan. During a battle in "The Gauntlet", Bradford and Xever go after the Turtles again and are exposed to mutagen when Chris Bradford stabs the mutagen container part of the bomb on top of the Wolf Hotel which washes him and Xever off the building. As Xever previously touched an exotic fish at a Chinatown Marketplace, the mutagen transforms him into a mutant fish that Mikey dubs Fishface. After his transformation, Fishface lives in the waters within Shredder's hideout. In "The Alien Agenda", Baxter Stockman creates a water-breathing rig for Fishface and mechanical legs that Baxter tries to get working. In "The Pulverizer," Fishface gains full control of his robotic legs. During the battle, he bites Raph with venomous fangs, causing him to experience delusions, fever, and nausea. In "Baxter's Gambit," Raphael learns more about Xever's past. 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.
Tiger Claw - Tiger Claw is a skilled assassin from Japan. As a young Japanese boy, Tiger Claw was mutated into a mutant tiger and grew up as a circus performer. He eventually became part of the criminal underworld when he was trained by Shredder. He is a master of all weapons and collects them from most warriors he defeats. He lost his tail in battle and searches for the person who took it. Tiger Claw will debut in season 2.
Foot Ninjas - The Foot Ninjas are ninjas loyal to Shredder and make up the soldiers of the Foot Clan. The Foot Ninjas wear black suits and masks. The masks appear to have bug-like eyes and have the Foot Clan logo on it (similar to the outfits worn by the Foot Ninjas from the Teenage Mutant Ninja Turtles films). The Foot Ninjas seem to never talk. Each of the Foot Ninjas fight with staffs, shurikens, katanas, and nunchucks.
Foot Bots - The Foot Bots are robotic Foot Ninjas that were created by the Kraang to strengthen the Foot Clan. The Foot Bots can adapt to every ninja moves and skills. During the Turtles' fight with the Foot Bots, the Turtles had to do unpredictable moves and skills to defeat them.
The Kraang (voiced by Nolan North) - One of the main villains of the series. The Kraang are a race of brain-shaped aliens from Dimension X that pilot robotic bodies and are responsible for bringing mutagen to Earth. The Kraang 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, Michelangelo managed to obtain a Kraang data storage device which revealed 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 was thwarted by the Turtles. In "Enemy of My Enemy," two Kraang operatives pilot a spacecraft when hunting the Turtles up to the point where they end up crashing a weapons trade involving the Shredder. The spacecraft was repelled by the Turtles. In "Karai's Vendetta," a 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 have started 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. After Shredder's mutagen plot was thwarted by the Turtles, the captive Kraang agent tells Shredder that they have a common enemy in the Turtles which led 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 Ninja Turtles destroyed the portal, the Technodrome and Kraang Prime had 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. This plot was thwarted by the Turtles.
Kraang Prime (voiced by Roseanne Barr) - The leader of the Kraang. Kraang Prime is a brain-shaped alien. When Kraang Prime speaks to other Kraang, it uses redundant speech, but when speaking to anyone else, it uses normal speech. speaks in a redundant manner. It first appeared in "Showdown" Pt. 1 where it 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, Kraang Prime confronts April O'Neil after she has been captured, who 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, Kraang Prime begins its plot to mutate the Earth. The Turtles arrive to fight Kraang Prime which thwarted the Earth mutation plot. Kraang Prime then emerges in a giant robotic body and chases after the Turtles. Leonardo manages to hold off Kraang Prime while the others get away. Luckily, Leo managed to escape with the captive humans as the Technodrome falls into the ocean.
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.
Biotroid - The Biotroid is a Yeti-type bio-mechanical suit that can be piloted by a Kraang. The Biotroid has powerful arms. It also has blades that are on its nipples and butt cannons, making it a very awkward villain. The Yeti Kraang was first used on a 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 caused Kirby to mutate when he tried to protect April from the mutagen. The Biotroid was defeated by the Turtles and the stealth ship is redirected towards the moon.
Purple Dragons - A street gang that has been extorting shop owners for protection money who have become allies with the Foot Clan. The Purple Dragons are commanded by Dogpound and Fishface.
Baxter Stockman/Baxter Fly (voiced by Phil LaMarr) - Baxter Stockman is an inventor who worked at TCRI. After being fired from the company for spilling copier toner, he plots revenge against the company and his co-workers. The Turtles mispronounce his name, which annoys him. The Turtles first encounter Stockman in rudimentary battle armor, while he attempts to break into a building. The Turtles defeat him, but Stockman obtains Donatello's T-Pod, which contains a military-grade artificial intelligence chip, and incorporates it into his battle armor. The next time the Turtles run into Stockman, his battle armor has upgraded itself. Eventually, the Stockman battle armor and the T-Pod merge into a destructive robotic being, which Mikey dubs "The StockmanPod". The 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. Following the incident with the MOUSERS, Dogpound brings Stockman to Shredder. Shredder threatened to kill Stockman for interfering with his plan to kill the Turtles, but spares him and comments on how his intelligence could be useful. In "The Alien Agenda", Baxter creates a water-breathing rig and his prototype mechanical legs for Fishface. After Karai returned to Shredder's hideout with the Kraang body and the controls to it, Baxter Stockman gets to work on studying the machine so that he can get Fishface's mechanical legs operational. In "The Pulverizer," Baxter Stockman gets the technology that he uses to successfully get Fishface's mechanical legs operational. In "Baxter's Gambit," Baxter Stockman tells Shredder of his full-proof plan. This plan secretly has him planning revenge on the Turtles(who have been foiling his plans), as well as Dogpound and Fishface (who have been abusing and threatening him), where he traps them in the Maze of Doom. During this time, it was revealed that Baxter Stockman was once expelled from school after he made a volcano project that contained real lava, which burned down the whole gym. When the Turtles, Dogpound, and Fishface make it to the end of the Maze of Doom, Baxter Stockman unleashes a giant robot called the Monster of Doom upon them. After the Monster of Doom is destroyed, Baxter Stockman uses his helicopter hat to get away from Dogpound, Fishface and the Turtles. In "Mikey Gets Shellacne", Baxter Stockman sets up a headquarters in the remains of TCRI so he can start his mutation. The Turtles find him while looking for a molecular centrifuge. As Baxter Stockman unleashes the MOUSERS to attack the Turtles, Dogpound also arrives. Dogpound manages to catch Baxter Stockman and the molecular centrifuge. Upon Dogpound seeing some mutagen tanks in Baxter's lab, Baxter states that he has been planning to make his army of mutants. Upon Baxter claiming that he can make Dogpound and Fishface normal, Dogpound places a mutagen collar around Baxter's neck as "insurance." Baxter's project is crashed by Michelangelo. When Michelangelo tricks Rahzar (Dogpound's secondary mutated form) into attacking the electric box, Baxter Stockman, Rahzar, and Fishface are shocked when the sprinklers are activated. By the time Baxter wakes up, Karai has arrived at his lab where she tells him that he works for her and Shredder now.
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, Shredder and Karai use two MOUSERS so that Splinter can receive Shredder's message to come out and challenge him.
Monster of Doom - An upgraded version of the StockmanPod that was created by Baxter Stockman. It was used by Baxter Stockman in his revenge on the Turtles, Dogpound, and Fishface. It took the combined strategies of both groups to defeat the Monster of Doom.
Snake/Snakeweed (voiced by Danny Jacobs) - Snake is a thug working for the Kraang as their getaway driver. The Turtles interrogate him and find out where the Kraang are holding April and Kirby O'Neil. During their mission to rescue the O'Neils, the Turtles crash a truck full of mutagen into the Kraang base. Snake is exposed to the mutagen and some nearby weeds, which turns him into a 12 ft. regenerating plant monster who Michelangelo dubs "Snakeweed". The Turtles fight Snakeweed. Leonardo lures him into a power core where Snakeweed 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. 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.
Vic/Spider Bytez (voiced by Lewis Black) - Vic is a crabby New Yorker in his 40s who videotapes the Turtles on his cellphone during a rooftop battle with the Kraang after one of the Turtles accidentally knocked down his satellite dish. Vic also insulted Raphael, which caused 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 Vic who is splashed with mutagen shortly after coming into contact with a spider. He mutates into a giant spider-like monster, whom Michelangelo dubs "Spider Bytez". Spider Bytez blames the Turtles for his mutation, and attacks them with acidic spit. During the battle, Spider Bytez' cellphone is destroyed. Just when Spider Bytez has the advantage, Raphael shows up and gains control over his temper. Spider Bytez escapes vowing to get revenge on the Turtles later.
Dr. Victor Falco/The Rat King (voiced by Jeffrey Combs) - Dr. Victor Falco is a scientist presumably working for the Kraang on an experiment involving a combination of mutagen and monkey DNA. Believing that he was close to developing a neurochemical that could make him psychic, Falco tests the chemical on his colleague Dr. Tyler Rockwell, transforming him into a man/monkey monster who 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", Falco 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, 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 mind control and defeats the Rat King.
Justin - After Karai pushes a control button on a machine at the World Wide Genome Project, a variety of animal DNA samples (examples being the DNA of a jellyfish, a beetle, an octopus, a cobra, and a cat) gathered by the Kraang are dumped into the mutagen resulting in the creation of a composite monster that Mikey simply names Justin. After Karai leaves, Justin attacks the Kraang until only the Turtles are left. Leonardo manages to use his katanas as an conductor of electricity to destroy Justin.
Traag - Traag is a lava-spewing, 15 ft. rock monster with regenerating abilities in service to the Kraang. The Kraang bring the giant through a portal that connects TCRI to Dimension X. Traag proves a challenge to the Turtles, but Leatherhead ends up dragging Traag through the portal back to Dimension X. In "Showdown," Traag was seen guarding the portal again where the portal has a force field around it. When the Turtles try to destroy it, they draw the attention of Traag and the Kraang. Leonardo uses the laser to disintegrate Traag.
Spyroach - Spyroach is a cockroach that was trained by Donatello to spy on the Kraang with special micro-equipment on it. Raphael has a fear of cockroaches. An accident that happened while it was spying on the Kraang caused Spyroach to fall into the mutagen and mutate into a humanoid cockroach with the equipment fused to its body. After escaping from the Kraang base, Spyroach ran into the Turtles and attacked them. Raphael was able to use the Shellraiser's cannon to knock out Spyroach, yet Spyroach managed to sneak away behind the Turtles's back. When the Turtles thwart the Kraang's robbery of the special lens, Spyroach catches up to the group where Spyroach defeats the Kraang. Then Spyroach attacks Raphael until Leonardo saves him. The Turtles then use the bug spray in order to get it out into the street where it gets hit by a truck and collides with the wall. Yet Spyroach survives and goes after the Turtles. Leonardo discovers that Spyroach is targeting Raphael and chased him until he got caught in the wet cement. It is then discovered that Spyroach had molted its skin and emerges in a second form where it can now fly. Spyroach then chases after Raphael while the Turtles are trying to get to the Kraang. When Spyroach grabs Michelangelo, Raphael ends up having to overcome his fear to rescue Michelangelo. Raphael then pilots his vehicle to lure Spyroach away so that the other Turtles can stop the Kraang. Raphael's fight with Spyroach ends up disrupting the Kraang's laser drill. Raphael then turns the laser drill on Spyroach, who ends up blasted apart, although a new Spyroach starts to form from one of the fragments of the old Spyroach.
Steranko (voiced by Fred Tatasciore) - Steranko is a Russian arms dealer with a diamond eye who is an old friend of Shredder's. He first appeared in "Enemy of My Enemy", where he meets with Shredder for a weapons deal. During the Turtles' fight with Shredder, Steranko was knocked out by the weapon that he was going to give to Shredder. Steranko's name was revealed in the credits.
Parasitic Wasp - A giant mutant wasp that hypnotizes the Turtles into protecting its egg by biting them. They nearly possessed the Turtles until they were broken free by Michelangelo and destroyed by the Turtles.
Newtralizer (voiced by Danny Trejo) - Newtralizer is a mutant newt with high-tech armor and weapons. It was result of the Kraang's experiments with the mutagen where it was considered dangerous to them. The Newtralizer takes on the Turtles when Donatello accidentally releases it from Kraang detention cell during the second attempt to rescue Kirby O'Neil. It is a carnivorous creature that eats Kraang. Mikey drives a car on top of the Newtralizer, allowing them to escape. The Newtralizer is shown to have survived after the Turtles leave.
Squirrelanoids - The Squirrelanoids are mutant squirrels. They have red skeleton like skin, glowing green eyes and a glowing green mouth. Their mouths contain extra mouths in their jaws. The Squirrelanoid is the result of a squirrel drinking from one of the mutagen canisters that fell from the Kraang's stealth-ship during the Kraang's fight with the Turtles as seen at the end of "The Mutation Situation." In "Invasion of the Squirrelanoids," the Turtles find the mutated squirrel and bring it back to the lair. The Squirrelanoid begins to multiply and mutate into hideous forms where they develop secondary mouths (similar to the Xenomorph in Alien) as they are given their name by Michelangelo.. When the Turtles were being overwhelmed by the Squirrelanoids, Splinter arrived and fended them off where they escaped into the tunnels. The Turtles end up going into the tunnels to keep them from reaching the surface and causing havoc. Using some popcorn and his knowledge of comic books, Michelangelo baited the Squirrelanoids into a grain pipe and flushed them into the septic tanks until Donatello can come up with a retro-mutagen to use on them. However, one of the Squirrelanoids managed to escape and attacked a sewer worker that found the bag of popcorn.
Chrome Dome - Chrome Dome is an android in a dark ninja outfit (which resembled Chris Bradford's full ninja outfit) that was Karai had the Kraang develop in her plan to target April O'Neil. In battle, Chrome Dome can wield two laser swords. During the Foot Clan's fight with the Turtles, Chrome Dome snatches April from her duel with Karai where the Kraang plan to reserve April and it now views both sides as it's enemy. Michelangelo was able to defeat Chrome Dome by running Chrome Dome's laser sword through it's chest.
Pizza Face - Pizza Face was a man who became a mutant pizza. Pizza Face looks like a pepperoni and mushroom pizza with arms, a mouth, and eyes made of pepperoni. Pizza Face will appear in season 2.
Metalhead - Metalhead is a durable turtle robot built by Donatello from salvaged Kraang technology. Donnie uses Metalhead to fight the Kraang. Metalhead also has many weapons at its disposal, such as a flamethrower and a laser cannon.
Spike/Slash (voiced by Corey Feldman) - Spike is Raphael's pet turtle. Raphael has a soft spot for Spike, and often talks to him about his feelings in private. This is important for Raph as 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. Raph often lets Spike ride around on his shoulder. In "Slash and Destroy," Spike mutates by drinking some mutagen that spilled in Raphael's room after he had confiscated it following an incident that nearly killed Spike. Upon understanding about what Raphael has to go through, Spike becomes Slash, obtains a mace for a weapon, and states to Raphael that they need to lose some dead weight when they head out to find a mutagen container. During the mission, Slash started attacking Donatello and Michelangelo where Raphael claims that the mutation has warped Slash's mind. As Slash plans to dispose of Michelangelo and Donatello, Raphael states that he didn't want this happening to his brothers. Slash states that there is no turning back now. Raphael ends up working to prevent Slash from disposing of Donatello and Michelangelo. Slash reveals that he has spent years watching Raphael train and knows what he can do. Raphael comments that he doesn't know all of his moves. Their fight wrecks the area where Leonardo is having tea time with a girl who was using the "mutagen" to pass as tea. Leonardo ends up showing up to help Raphael only to knock him down. During the fight, Raphael hits a vulnerable part on Slash's arm and falls off the building. When Raphael looks over the building, Slash's body is gone as the Turtles suspect that Slash had gotten away.
Dr. Tyler Rockwell (voiced by Frank Welker) - Dr. Tyler Rockwell is Victor Falco's missing science partner who was unknowingly used as a subject in Falco's experiments involving mutagen, a neurochemical, and monkey DNA. April and the Turtles learn Rockwell has gone missing and investigate. They discover that Falco had transformed Rockwell into a monkey-like monster that can sense emotion. So far, it hasn't been shown what Tyler Rockwell's human form looks like.
Mr. Murakami (voiced by Sab Shimono) - Mr. Murakami is a blind, 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."
Sir Malachi - Sir Malachi is a mutant sparrow wizard that will appear in season 2. He wears medieval-style hood and tunic and carries a staff with an egg-shaped decoration on top. The creators 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.