Introducing: The Ultra-Skull himself,
KAHN: The Conqueror. A villain who is dead set on taking over the world, no matter what methods are used. From mooching off of an underwater king, to stealing powers from the Chimera, and everything in between. His skull is radioactive, so he can connect to radio stations and speak through them without any form of transmission. He can also breathe Underwater and in space, because he can't physically die. And he's the only skeleton with functional muscles, which gives him an edge over all the scrawny living bones around the graveyards.