“ If people want to hate me, I can't stop them. But it's not going to stop me from doing my job. You wanna know why? Because I'm awesome. ”

Rex Salazar is a teenage (18 in Season 3) amnesiac EVO(Exponentially Variegated Organism) with the ability to grow and build fully functional mechanical weapons and equipment out of his body at will. Prior to the Nanite Event, he was one of the initial recipients of a controlled batch of nanites. Unlike a majority of EVOs, Rex has control over his nanites and is the only known being capable of curing other EVOs. Since childhood, Rex was employed as a secret weapon for Providence, a global organization dedicated to protecting the world from rampaging EVOs.

Unintentionally, Rex disappeared six months into the future and returned to Providence with a new regime he disapproved of. He willingly left Providence for the time being to join a defect group and rebel against the corrupted organization. After gaining the god-like abilities of the Meta Nanites and defeating the Consortium, Rex cured the entire world of EVO mutations (Although there still remaining Nanites), with himself and Bobo Haha being the only remaining known EVO's in the world, With his abilities reserved, he continues to fight for Providence.