"!Tsetaerg eht m'I dna osreveR lE m'I (I'm El Reverso and I'm the greatest!)"
―El Reverso "before" the fight
Carlos Santiago Dominguez-Martinez, better known as El Reverso is a wrestler and superhero who lives his life in complete reverse. Everyone else's life seems to be his past.
In episode Tub Boys, it's shown that this was actually a curse given to him by a mummy when he displaced a scarab amulet from a pyramid. The curse was overcome later on though, because El Reverso started speaking (not) in reverse order by the end of episode "San Diego Breakfast".
From the mask design and the Spanish name, it's assumed that El Reverso is Mexican.
In Cyanide & Happiness: Freakpocalypse part 1, Coop can find a book in school library called "seimmuD roF gniltserW"/"Wrestling For Dummies" (by El Reverso). Coop comments that "Maybe I'll do THAT when I grow up."
Presumably, El Reverso wrote a book (possibly) about how to become a professional wrestler like him.
In Balls Deep, an El Reverso themed hockey table game called "YEKCOH ed ERIA"/ AIRE de HOCKEY is seen.
