List of Invader Zim characters

From the left: Top: Zim, Zim in his human disguise, GIR, GIR in his dog disguise, Dib, Gaz,
Bottom: Professor Membrane, Ms. Bitters, Almighty Tallest Red and Almighty Tallest Purple.

Invader Zim is an American animated television series created by Jhonen Vasquez. Twenty-one of the twenty-seven episodes originally aired on Nickelodeon from March 30, 2001 to December 10, 2002 while the remaining six were originally released on DVD on October 12, 2004. The recurring cast includes voice actors Richard Steven Horvitz, Rodger Bumpass, Kevin McDonald (The Kids in the Hall) and Wally Wingert. Vasquez voices parts in the show. The show was cancelled early in its run and some episodes were unfinished. The show ran for two seasons before its cancellation.

Overview

  = Main cast (credited)

  = Recurring cast (4+)

  = Guest cast (1-3)

Actor	Character	Appearances
		First	Last	Season 1	Season 2	Christmas Special	Comic Series	Enter the Florpus
Richard Steven Horvitz	Zim	"Pilot"	Invader Zim: Enter the Florpus	Main
Rosearik "Rikki" Simons	GIR			Main
Andy Berman	Dib Membrane			Main
Melissa Fahn	Gaz Membrane			Main
Rodger Bumpass	Professor Membrane			Main
Olivia d'Abo	Tak	"Tak: The Hideous New Girl"		Main
Kevin McDonald	Purple	"Pilot"		Also starring		Mentioned	Recurring	Main
Wally Wingert	Red			Also starring			Recurring	Main
Lucille Bliss	Ms. Bitters		"The Voting of the Doomed"	Also starring		Silent cameo	Recurring	Silent cameo
Jhonen Vasquez	Minimoose	"The Most Horrible X-Mas Ever"	Invader Zim: Enter the Florpus	Does not appear		Main

Main characters

Zim

Zim (voiced by Richard Steven Horvitz, Billy West in the pilot and Melissa Fahn as a newborn in his flashback of "Parent-Teacher Night") is an incompetent Irken who is arrogant, foul-tempered, reckless, overzealous, uppity, impatient, impulsive, naive, megalomaniacal and convinced of his own greatness. He dreams of regaining his leaders' trust by taking part in Operation Impending Doom II, so Zim is assigned as an “invader” to Earth, a planet which the Almighty Tallest believe has little to no chance of existing. However, against all odds, Zim makes it to Earth and establishes a base on a fake conquest mission. Zim disguises himself as a human child using a hairpiece to cover his antennae and contact lenses to make his eyes look normal.

No one realizes that Zim is an alien, except Dib and Gaz. Zim has no friends, and often physically harms his classmates if they attempt to befriend him. However, despite this, they always naively defend him when Dib tries to warn them that Zim is a space alien. Zim is equipped with a PAK, a cybernetic backpack-like device with life support and (among other gadgets) long, retractable robotic spider legs that enable him to move about quickly and climb almost any obstacle.

Zim constantly schemes to enslave or destroy mankind, and despite his access to potent Irken technology, his plans are never successful. Zim also has a high opinion of himself, and will sometimes refer to himself in the third person.

GIR

GIR (Garbage-issue Information Retrieval Unit) (voiced by Rosearik "Rikki" Simons) is a malfunctioning and dimwitted robot SIR (Standard-issue Information Retrieval) Unit who was assigned to Zim. He was built by the Almighty Tallest out of SIR unit remains from a trash can and rubbish they found in their pockets and was subsequently passed off to Zim as a "top-secret" and "advanced model". He disguises himself in public by wearing a green dog suit, which fools most humans, despite looking and acting nothing like an “Earth dog”. Out of the pair, GIR has more interaction with Earth's social and cultural life-style. His personality is cheerful, friendly, and easy-going. GIR also has a love for Earth that his master does not share. Throughout the series, GIR has demonstrated talents such as cooking and dancing.

GIR has no sense of who is a friend and who is an enemy. He also rarely understands the severity of the predicaments he finds himself in unless it involves pain or very severe danger. However, he often understands it more than his master and has on rare occasions predicted the correct outcome of a very dangerous situation.

GIR's upbeat, clueless, thoughtful, and friendly personality is a contrast to Zim's self-centered, imperious behavior. GIR enjoys taking part in Earth's culture, while Zim distances himself from it to complete his mission. Since GIR does not usually obey Zim, this often results in Zim growing furiously with GIR. However, GIR and Zim occasionally seem to care for one another.

Dib Membrane

Dibert "Dib" Membrane (voiced by Andy Berman) is a young eccentric paranormal investigator who spends his time studying the supernatural and paranormal, as well as thwarting Zim in his schemes to take over the world. Dib is generally mocked, bullied and hated by his classmates because they see him as annoying and crazy. Even though Dib’s classmates tend to bully him, he is reluctantly determined to defend and save them from Zim’s evil schemes anyway. Zim and Dib often fight and hate each other, as Dib, knowing Zim is an alien bent on destroying the Earth, is determined to protect planet Earth and humankind. While they are often portrayed as mortal enemies, Dib and Zim have at times been forced to work together as reluctant teammates. Despite their feud, an unfinished episode of the series titled "Mopiness of Doom" revealed that Dib lost interest in Zim and the paranormal while Zim gave up on destroying Earth and mankind, though he later came back when Dib changed his mind and decided to hunt Zim.

Dib is self-conscious over the size of his head, and usually overreacts when people point out its largeness. It is revealed in some episodes that his head serves multiple purposes; in the episode "Halloween Spectacular of Spooky Doom", it served as a portal into other worlds.

People such as the police, the F.B.I., NASA Place, and “The Swollen Eyeballs” (a secret society which Dib is a member of, dedicated to discovering the paranormal and separating the fake superstitions from the real ones), tend to find Dib annoying. However, a few of these people realize just how sane Dib is and are kind enough to help him at times. Dib's secret codename as part of this group is “Agent Mothman”. Because he has cried wolf so many times, Dib finds it very hard for people to believe him, and is thrilled on the rare occasion when he finds someone who does. Nonetheless, he is willing and prepared to strongly defend the paranormal field of study whenever someone makes fun of it or claims it is not a real field of study.

Before the comic book series was launched in July 2015, it was unknown what Dib and Gaz's surname was, if they had one at all. At the time of the television series, series creator Jhonen Vasquez claimed that their father Professor Membrane was actually using his first name in his title. However, the comic series has had Dib addressed as "Dib Membrane" multiple times, with the first being in a pre-Issue 0 and in an official Issue 5, with "Dib Membrane" being confirmed as the character's name in Invader Zim: Enter the Florpus.

Gaz Membrane

Gazlene "Gaz" Membrane (voiced by Melissa Fahn) is Dib's younger sister who enjoys playing video games, drinking soda and eating pizza, particularly from her favorite restaurant Bloaty's Pizza Hog (a pastiche of ShowBiz Pizza Place and Chuck E. Cheese's). If and when someone or something stands in the way of her getting those things, she is extremely vengeful and quick to lose her temper. Like her brother, Gaz knows that Zim is an alien, but does not care because she believes he is incapable of conquering the Earth. Gaz very rarely displays happiness, and is usually humorless and ill-tempered. However, she is sometimes amused at Zim and Dib's misfortunes.

She seems to be very underestimated, especially in the episode where she saves Dib’s life from Zim. Also, she was going to be Zim’s love interest. In the series, Gaz has either a lukewarm or a cold relationship with most of the other characters. She mostly dislikes her brother Dib, although she has been rarely shown to care about him. The only exception to all of the people she does not get along with might be her famous father, Professor Membrane. He seems to have a warm relationship with Gaz, even though it is not shown all that often.

Gaz has a very vengeful and creepy way of stalking people who have significantly pestered, or upset her—like Dib or the video game-crazed boy named Iggins. She has displayed amazing abilities in two episodes ("Battle Dib" and "Game Slave 2").

In the episode "Lice", it shown that Gaz can endure pain (in that case, the lice eating her scalp) and even calls the students who complain about the pain "whiners". Another example of Gaz's toughness is shown in "Dark Harvest" when Zim steals and replaces one of her organs with her Game Slave, but she continues to play her game, even though it is inside of her.

Secondary characters

• Almighty Tallest (Kevin McDonald as Purple; Wally Wingert as Red): Co-leaders of the Irken race. The Irken Empire has a hierarchal class structure wherein shorter individuals are both figuratively and literally looked down upon. The tallest Irken born in a specific generation takes command of the Empire as "The Almighty Tallest". Since Red and Purple, the two current Tallest, are exactly the same height (in addition to being identical in appearance aside from their eye colours), they share equal and high-supreme power. While the Tallest function mainly as figureheads, doing little to organize the society (preferring to lounge around, goof off with one another, and eat snacks), they do hold absolute power over the populace, just below the Irken Control Brains. They travel around the galaxies to observe and supervise Operation Impending Doom II in the Massive, the largest and most powerful starship in the Irken Armada. They appear to mostly use their unlimited powers of state to amuse themselves. They tend to be petty, and often bully and cause misery to their Irken subjects, having a childish outlook of their power. Red seems to have a slight focus on conquest, and is usually seen as being more intelligent than Purple, who commonly acts comically goofy. Red and Purple are always seen together and get along well, acting in a brotherly manner toward each other as they enjoy sharing in their power, despite their personalities contrasting. Along with their quirky obsessions with snack food and puppets, they also greatly enjoy poking fun at Zim. They both hate Zim due to his annoying, rebellious, sadistic, and destructive behavior (as does the rest of the Irken race).
• Professor Membrane (Rodger Bumpass): A scientist who hosts the popular television show Probing the Membrane of Science and the father of Dib and Gaz. Membrane's scientific abilities are offset by incredibly poor parenting: his primary method of managing his children is by way of a floating digital projection screen-and his messages to them are often not only prerecorded, but woefully out of date. Professor Membrane is very rarely ever home due to the world always needing his help. However, he does make it a point to once a year have a family night with his kids and spends Christmas with them. He has sometimes urged Dib to give up on the paranormal and focus on "real science". His scientific achievements ranged from useful to bizarre, ranging from restoring power during a blackout to useful inventions like "SuperToast". Professor Membrane's first name is unknown. He has the ability to fire lasers out of his hands, which Enter the Florpus reveals to be because he replaced his arms with robotic prosthetic arms after his real arms were bitten off by sharks.
• Ms. Bitters (voiced by Lucille Bliss and later Candi Milo in some video game adaptations): The teacher of Zim and Dib's class. She is a tall, slender, and elderly woman who is very grumpy, devoid of any compassionate emotion, and possesses a cynical dislike for life. She is often shown applying the school's unreasonable rules, or applying unreasonable punishments of her own invention for comedic purposes, often on Dib. She often slinks around to the sound of a cicada and is often shown literally emerging from people's shadows.

Recurring characters

• Tak (voiced by Olivia d'Abo): A female Irken who had an unfortunate encounter with Zim. The incident trapped her in a building on Devastis, the Irken military training planet, causing her to miss her chance to take the test to become one of the Irken Elite Soldiers (and an Invader). Instead, she was relegated by a Control Brain to janitor duty on Planet Dirt for 70 years, but she escaped to hunt down Zim. In "Tak: The Hideous New Girl", she comes to Earth, disguised as a human girl, and attempts to usurp Zim's mission and destroy Earth. She is thwarted by Zim, GIR, Dib and Gaz, who reluctantly work together to defeat her.
• MiMi: Tak's SIR unit. Her disguise is also holographic, to be generated as a black cat. Like GIR, she is easily distinguishable from other SIR units, having a large robotic claw for an arm. She has no dialogue in the show. MiMi is taken over with GIR's personality and is dismembered by Tak in the process during the end of "Tak: The Hideous New Girl".
• Piggy: A live pig that GIR has been seen having tea and watching movies with and seems to have a fascination with piggies, because he also has a large collection of rubber ones, which are thrown into a time machine by Zim to destroy Dib.
• Computer (Jhonen Vasquez): Zim's computer is normally seen talking with Zim. He is scattered around the house and base so Zim can talk to him whenever he needs to. The computer also seems to display defects, similar to GIR, in both that he lacks information on Earth and will occasionally change his voice tone to a much harsher version at usually completely unnecessary times and situations. In the episode "Invasion of the Idiot Dog Brain" Computer's brain is replaced with GIR's.
• Roboparents: Zim's helpers that guard his base and help make him seem more human. The Roboparents are poorly built and have an utter lack of normal parental behavior. The Roboparents frequently act inappropriately, or attack visitors to Zim's house, although in "Parent-Teacher Night" they actually reassured a parent about their son not making a soccer team, impressing even Zim.
• Minimoose (Jhonen Vasquez): A floating purple moose-shaped creature with stubby legs and antlers, Minimoose is introduced as Zim's other sidekick. The series was cancelled before he could make his official debut in the unfinished episode "Nubs of Doom"; his only appearance was in the final episode, "The Most Horrible X-Mas Ever".
• Invader Skoodge (Ted Raimi): An unlucky short and chubby Irken Invader who was assigned to planet Blorch, home of the slaughtering rat people, due to his shortness. He was the first Invader to successfully conquer a planet in Operation Impending Doom II, but is prejudiced against by the Almighty Tallest, who proceed to launch him into the planet as the first shot of the destruction. However, he survived this incident and returns in “Hobo 13”. Skoodge is loyal to the Almighty Tallest, despite the fact that they judge and resent him due to his short stature.
• Keef (Danny Cooksey): A clingy child that attends the Skool with Zim. He is seen to be overeager to have a friend in the second episode, "Bestest Friend", in which Zim befriends him to appear normal. In the episode, Zim grows tired of Keef's constant presence, and when Keef's "surprise party" for Zim jeopardizes base security, Zim tricks Keef into thinking a squirrel was him by replacing his eyes with robot eyes. He is seen in the background in numerous episodes, and has a few lines in "Lice".
• The Swollen Eyeball Network (various): A group (including Dib, known within the group as "Agent Mothman") who are determined to prove the paranormal. Some Agents are Agent Mothman (Dib's alias), Agent Darkbooty (Revealed to be a NASA janitor), Agent Tunaghost, Agent Disembodied-Head, and Agent Nessie. Found in episodes "Battle of the Planets", "Battle Dib", "Zim Eats Waffles" and "Gaz, Taster of Pork"

Minor characters

• Lard Nar (voiced by Fred Tatasciore): The Vortian leader and captain of the Resisty, a group of ragtag aliens whose goal is to defy and ultimately bring down the Irken Empire due to having their planets conquered. Captain Lard Nar’s only appearance is in Backseat Drivers From Beyond The Stars. He is from the planet Vort, which has since been conquered by the Irken Empire. Lard Nar is a Vortian scientist who had contributed to building the Massive before the Irken Empire turned on Vort. Captain Lard Nar is very intelligent, but known to be nervous and make hasty decisions. Nonetheless, he cares about his Resisty crew, and was able to save them all from crashing into the Earth in Backseat Drivers From Beyond The Stars by evacuating them all from his starship. He also activated “Shrinky Self-Destruct” on the Vort starship to protect its secret technology from being stolen by any alien thieves.
• Bloaty (voiced by Rosearik Rikki Simmons): The owner and/or mascot of the Chuck E. Cheese's-like restaurant, Bloaty's Pizza Hog. He is mostly seen in commercials. He was only seen out of his pig costume once, in the episode "Bloaty's Pizza Hog," and apparently has an eating disorder. He is an elderly, morbidly obese man, to the point of being fatter out of costume than in it.
• President Man (voiced by Jeffrey Jones): The President of the United States who appears in the series, with his most significant role being in "The Girl Who Cried Gnome". He is essentially a figurehead, being the incompetent fool he is. The stupid things he has done include leaving the coat hanger in his suit, giving up his power to "Santa" (who was really Zim in disguise), and trading the fate of a "crisis" for Ninja Star cookies, which he is exceedingly fond of.
• Nick (Jhonen Vasquez): Excessively happy human held captive by Zim for experimentation. His most notable feature is the enormous drill-like "happiness probe" in his head. He appears in "Zim Eats Waffles", "GIR Goes Crazy And Stuff" and "The Girl Who Cried Gnome".
• Sizz-Lorr (Jim Wise): Zim's chef boss, a tall, powerful, and very heavyset Irken Frylord who appears in one episode, "The Frycook What Came from All That Space". He kidnaps and takes Zim back to his true place of exile, “Shloogorgh's Flavor Monster” on the planet Foodcourtia as retribution for Zim abandoning his true assignment as a Food Service Drone before the first episode. Zim just barely escapes Sizz-Lorr while fleeing his capture on Foodcourtia, but only due to the gravity increasing from a massive amount of snacking, which prevents anyone from leaving the planet for 20 years.
• Bill (Adam Paul): Moronic paranormal investigator who believes that ghosts, the Loch Ness Monster, and Bigfoot are fake, while cereal box characters such as Count Chocofang and Frankenchokey are real. Seen in "Career Day" and "The Sad, Sad Tale Of Chickenfoot".
• Mr. Elliot (Simon Scott Bullock): Gaz's teacher. Appears to have a positive outlook but is not revealed to have very much intelligence. Seen in "Gir Goes Crazy And Stuff", "Gaz, Taster of Pork", "Parent-Teacher Night", and was going to appear in the unfinished episode "Simon sez Doom".
• Iggins (Paul Greenberg): Gaz's enemy and gaming rival. An obsessed video game nerd who was prominently featured in the episode "Game Slave 2." Iggins takes the last Game Slave 2 console, (and the American version of Vampire Piggy Hunter), thus incurring the wrath of Gaz, and he goes crashing down to earth in an elevator after giving her the Game Slave 2. Although at first it appears he had perished from the crash, Iggins exuberantly bursts forth from the wreckage, completely unharmed, while dramatically yelling his name at the very end of the episode. He appears again in “Walk For Your Lives”, but has a non-speaking role, seen getting arrested by a cop for just doing nothing.
• Peepi: The class hamster who was turned into a giant monster by Zim in "Hamstergeddon".
• Gnomes: Robotic gnomes protect the exterior of Zim's house when people are in the yard, with the ability to shoot lasers from their eyes.