Carlos "King without a Crown" Rivera
About
He fought Yabuki Joe to a draw, two weeks before his world title match. After that, he fought for the world title against José Mendoza, but was KO'ed in the first round. It's later revealed that he has permanent brain damage from the fight and can't remember anything anymore, thus ending his career. After that, he goes missing but shows up at Joe's match with Harimau.