Sans is the weakest monster in his AU and people wonder how he has survived for this long. He helps the human avoid death, but he uses the human and finally succeeded to kill his brother, Papyrus. He always calls his brother a piece of s***t and he hates him for being so abusive. He insults his brother and constantly plots on ways to kill him. He's also known as a thief, constantly pickpocketing people for money. Overall Negativetale Sans is the complete opposite of his Undertale counterpart.