Mae is the role of Sans. She is the final boss of the Genocide Route and younger sister of Papyrus.
She is often smiling, but in the True Pacifist Route, admits her smile is fake. She greatly mourns the loss of her brother, but doesn't let anyone see it. She has MDD, and is sometimes insane. She often tells jokes and puns to lift everyone's spirits, but is often jeered at. She is very protective over Papyrus, stating she "can't lose the other". She keeps Sans's death a secret, and not even Papyrus knows about it. She made a grave for Sans, which she visits every day. She is good at keeping secrets, but not at keeping promises. There is one promise she still keeps after 9 years.
She has white bones and no hair. Her pupils are white circles, as opposed to hearts. She has a small crack in her skull, which goes through her left eye socket, and several scars on her arms. Her fingers levitate over her actual hand. Overall, of all the abused monsters, she's the least damaged.
She wears a white T-shirt, blue shorts and red boots. She has a purple hoodie hung around her hips, and white bloody bandages wrapped around her arms. Her clothes are torn up.