He was a normal swap papyrus. Until a human named chara killed all the underground over and over. Swap papyrus just watched his friends and his brother die. He had enough. So he decided too do his own genocide by killing everyone and his brother swap sans.the most thing he regrets. Killing his own brother.He is 16 feet tall and 3-6 feet. His name is swap papyrus but papyrus for short.He is called dustswap papyrus. Full info: https://undertale-au-fanon.fandom.com/wiki/Papyrus/Dustswap