Dib Membrane

Dib Membrane is the tritagonist and general hero antagonist of Invader Zim. Dib is a young, eccentric boy who possesses a fascination with unexplained paranormal phenomena, such as ghost hunting, Ufology, and cryptology, as well as with the supernatural and occult.

He intercepted the words spoken at the Great Assigning on planet Conventia in the first episode with his laptop. Six months later, he noticed a strange, green foreign exchange student enter his classroom. Dib tried his best to convince the world that it is in danger, but nobody believed him, due to previous erroneous claims of supernatural beings. Since then, he has made it his mission to protect his oblivious home from Zim's schemes against all odds.

Appearance
Dib is an 11-13 Earth years old and resembles his father, Professor Membrane. Both have black, scythe-like hair. He wears a black trench coat, a blue shirt with a logo of a grey face and glasses. In Dib's Wonderful Life of Doom, Dib's got more jagged and bigger with age. Many people claim that Dib's head is big, a running gag in the show; but it's not visibly bigger. The redesign process God  Save the Dib, however, actually gave him a bigger head.

Role In The Series
While he is the hero of the show, he has shown to be a very antagonistic character, often doing mean things to other characters to reach his own personal goals (the most notable being that he once gave his own little sister a curse that made every thing she ate taste like pork so he could see what it did to humans) as well as doing crazy and often life threatening things just to stop Zim. He is also almost always stalking him. He has a sister named Gaz Membrane.

Trivia

 * Despite being archenemies, Dib has temporarily allied with Zim numerous times through out the show. Most notable times are in Hamstergeddon and Tak: The Hideous New Girl.
 * While Zim and Dib hate each other, they actually need each other. It is revealed in the cancelled episode, Mopiness of Doom, without Dib, Zim would lose interest in his mission and without Zim, Dib cannot prove to the world that Zim is an alien.
 * Out of all the characters in the show, Dib is the most antisocial; He has no friends, and he constantly gets bullied by the other Skoolchildren.
 * Dib is Jhonen Vasquez's favourite character in the show.
 * Dib Shares a Similarity with Oka Ruto from Yandere Simulator:
 * They Both stalk characters for proof that they are Supernatural Beings. (Dib: Zim, Oka: The Basu Sisters, Respectively)