I was originally Undertale626.
My Sans, Assasin! Sans has a backstory. Here it is: He kills every human that does genocide in the underground. Many humans reset or came back. Many of them injured him horribly. In his spare time, He stalks other Sanses or plays games. He wants to kill all the genocide humans because a human had destroyed his AU. He destroyed the human's reset, save, and load. Then he killed the human. Now he can't forgive genocide humans. He kills the ones that have defeated Asgore or Sans. His jaw is missing, His eye socket forever bleeds. He talks by using a special robotic scarf. It gives him a voice. Many confuse him with Geno! Sans because there is a Glitch on his eye socket, He covers the internal bleeding.