He is a skeleton covered in a black goop, he is the guardian of negativity. He's the boss of a group known as the 'Bad Sans' that live him his castle, the group consist of Killer, Horror, Dust, Cross,Error.He lives off of other peoples fears and negative emotions they make him stronger but he doesn’t like using the negativity from his squad.He likes to read.He destroys AU’s (alternate universes) with his squad. He is from an au called Dreamtale.he has a twin named Dream who he doesn’t like.