|Invader Zim, or just Zim, is an Irken Invader. He goes to other planets found suitable for conquest and conquers them. In his society, people are ranked in size, and he's a squirt. He gets teased by anyone bigger
than him. He was sent to Earth as a joke with GIR. The mission was a joke but humans were found and the process of domination began. Now he pursues a way to take over Earth.
Dib is a small boy with a big head that tries to prove Zim is an alien
to the public. In all his attempts, he is doomed to fail. He is son of
Professor Membrane, a genius and host of the popular kid's show "Pick
Your Membrane", and brother to Gaz. No one ever notices him for his
brilliance, only for his large head. Therefore, no one takes him
Gaz is Dib's sister. She does not help Dib in his quest to expose Zim,
rather she tries to enjoy the simplicities in life. She enjoys t.v.,
junk food, and spoiling her brothers plans. When someone gets in the way
of her simplicities, she goes after them with a vengence. She finds Dib
annoying and takes any small chance chance she is given to mess with his plans to expose Zim.
Professor membrane is a genius host of the televsion show "Pick Your
Membrane". He is father to Dib and Gaz. He is unaware to Dib's plans, no
matter how many times Dib tries to tell him or he tries to find out. He
is very rarely seen outside of his lab for he does "very important
work". He has created some of the many things that aid the characters on
the t.v. show.
Ms.Bitters is the school teacher for Zim, Dib, and Gaz. Her history is
unclear, but it is believed she has been around since the beginning of
time and the school was built around her. She is mean, cruel, and
completely abnormal, the one thing she shares in common with all
Gir is Zims robotic assistant. All invaders are given one, but his is
different. Rather than top of the line technology, it was built out of
scrap. It was another joke made by the rulers of the Irkens. Gir has
little sensibility and is often unreliable to Zim. Gir is insane.