Louie is a young paranormal investigator like Dib. Unlike Dib, he wants to rule the world rather then save it. His personality varies around being bigoted (especially around cryptids as he thinks they are all demons), lazy, misgynistic, self righteous, wildly insecure, paranoid and genocidal. People criticize him and whenever he notices, he either enters a world of denial or just recklessly attacks the offender.
Despite being alienated by many kids in his school, he always enters a state of extreme delusion. He would even go as far as to kidnap people to witness his "victories". It is implied he might have supernatural powers as sometimes his eyes would glow red, whenever he is annoyed or offended he would talk in a demonic voice, levitate, and hurl someone across a yard possibly with force-like abilities. He is an antagonist to all characters. example - Zim and Tak who are aliens are often targeted by his bigoted slander (but it is shown he has a crush on Tak). He constantly taunts Dib for being often unsuccessful and tries to take credit for whenever Dib redeems himself , and grew a bigger resentment when he learns of Dibs olerence towards some cryptids and sensitivety towards baby animals And later his friendship with Tak.
He tends to mistreat GIR. He fears he might lose his "reputation" whenever he loses a fight (espically whe it's with Gaz or Tak as they are both girls) despite getting several reassurances from kids, teachers, parents and members of the Swollen Eyeball society that their opinion of him has already reached the point were it can't get any lower. Often times when he wants to "do what's best for humanity" he would enter a state of propagandist antics that put innocent people and main characters in physical endurement. But he never recognises his crimes or sins, much less show any sign of remorse or take responsability.
He often would try to inforce his opinion upon others when when they refuse, ignore or avoid him. He has sadistic environmental views saying that "God intended the seas to be filled with oil, all trees to be cut down, the air to be filled with toxic fuems and the ground to be covered in cement and concrete". Louie is best discribed as a soft spoken lunatic whose delusions often come at great expense and sometimes danger to the characters. Also he can bring Earth to its end in about 12 minutes. He is ultimately killed by a vampire named William.