Zim

"Zim came in peace without harm. I can hardly imagine that Nella forgave him with misunderstanding. I can comprehend that Zim is not the only one who is friendly to us Earthlings since he was betrayed from the Irken Empire."

--Su Ji-Hoon, Coming in Peace

Zim is the titular protagonist of the series by the same name, Invader Zim.

Zim is a member of the alien Irken race, and a former Irken Invader; however, since his actions usually lead to disaster (having nearly destroyed the Irken homeworld during Operation Impending Doom I) his leaders, the Almighty Tallest, banished him to Foodcourtia. While there, however, Zim heard of Operation Impending Doom II, and - obviously not understanding the purpose of his previous exile - "quit being banished" and ventured to Conventia in the hope of getting an assignment. Chagrined, the Almighty Tallest sent him on a "secret mission" to Earth, in order to keep him occupied and away from the real Operation Impending Doom II. After arriving on Earth, Zim enrolled in the nearest elementary school to begin his infiltration and gather information about the indigenous race. There, he became quick rivals with Dib.

Zim's primary desire is to conquer Earth, mostly to prove his superiority and impress his leaders. However, as mentioned by Gaz in an Invader Zim episode, "Bloaty's Pizza Hog," "he is so bad at it."

Although he is the protagonist, Zim is morally, and ethically a villain, being an overall fairly unsympathetic character, though he occasionally shows some kindness towards certain characters, (such as GIR in an Invader Zim episode, "Walk of Doom"), and is usually only causing chaos and destruction for either himself, his own race, or Earth. As well, almost everyone else he comes into contact with at any time. His unawareness of his destructive actions is most likely the result of him being a "defect", as revealed in the cancelled Invader Zim episode "The Trial."

In When the Cold Breeze Blows Away, he is forgiven to Dib and Gaz, and at the same time, he eventually became friends with the Preschool Girls and Su Ji-Hoon, and eventually formed the Irken Rebel Army (IRA) with the help of defected Irken soldiers, and wanted to overthrow the Almighty Tallest in order to reform the Irken Empire into a democracy, and destroy the Coalition of the Red Star. Soon, he is converted into a devout Roman Catholic and a proud supporter of the Grand Alliance, and he also is a peace activist, as he later learns that the Irken Empire's invasions are against God's will and are the works of Satan.

Appearances
Zim's appearance, like that of most of the Irken race, seems to be based off the typical "little green men from outer space" stereotype.