TS!Underswap Wiki

"you're the bad guy. cause, believe it or not, your existence is a crime."

― Crossbones,[[source]]

Sans is the brother of Papyrus and a major character in TS!Underswap. Under the name Crossbones, he is a vigilante superhero sworn to protect the Starlight Isles from danger. He is the first monster Chara interacts with upon exiting Ruined Home.



On duty, he wears brown boots with grey ends, dark blue sweatpants with two light blue streaks on each side, a light blue jacket with grey sleeves and two bones making a cross (probably a reference to his identity as Crossbones), a blue cape, and a light blue mask to conceal his identity.

Off duty, he looks considerably similar to his Undertale counterpart, but with a few changes, like his hoodie having drawstrings and his slippers being pink.

When either serious or angry, Sans' pupils will disappear, an interesting detail that was also common in the original Undertale game.


As the masked vigilante Crossbones, he is very serious in his heroic duties of protecting the Starlight Isles and it can be assumed that the same could be said for capturing humans. However, the names for some of his super hero gear can sound somewhat immature, mainly his "bed sheet of justice" and "Punishment Shack", and puts on a dramatic and stunning persona when he's wearing the mask. Crossbones prefers to keep his identity a secret and seems to be worried about getting exposed.

When off duty as regular old Sans, he tends to be laid back and a joker, who also knows how to deal with his brothers' child-like outbursts. He also likes pranks, especially when it's using Papyrus' own gadgets against him. He may act different while he's off duty to avoid drawing in any suspicion.

Overall, Sans can be very stern and does not like the idea of killing, which is why he prefers harmless gadgets over weapons. He is aware if Chara has hurt any monsters and isn't afraid to confront them over their actions. He is also very observant, as shown on a Genocide Route Sans will notice the dust on Chara's clothes before confronting them.

Main Story

At the beginning of Starlight Isles, he will give a short speech about the player's behavior depending on which route they took once they arrive in a clearing. He will then appear behind them and brandish his ketchup gun, ending the demo.

In the True Pacifist post-credits scene, he appears wearing his casual outfit alongside his brother, Papyrus. He briefly discusses the future of the game, comforting Papyrus on the wait until his "grand reveal."

Sans has made an agreement with Asriel (known as the pen name "A.S Dreamer") to create official comic books that "accurately" portray Crossbones' many heroic adventures.[1]





  • Crossbones calls his cape "the bed sheet of justice." [2]
  • On the side, Sans sells "super dogs" as Crossbones merchandise. [3]
  • After defeating his enemies, Crossbones sends them to "the punishment shack" to think about what they did wrong. [4]
  • Sans's superhero outfit went through many iterations before his current "Crossbones" identity. At one point, he called himself "Super Sans." [5]
  • All of Sans's previous designs are considered canon, having been each of his "prototype suits."
  • There will be a series of official Crossbones Comics that exist in-universe, which will also be featured as online comics. They may or may not also be featured as in-game collectibles, too. [6]
  • The bones on his drawstrings are based off of the official Fangamer hoodie. It is unknown if the hoodie's other features have been adapted, however.
  • Unlike Undertale Papyrus wanting to get into the Royal Guard, Sans has no interest in joining the Royal Navy and flies solo instead.
  • Currently, the only monsters who know Crossbones' secret identity are Papyrus and Alphys.
  • He shares the same name of the vigilante Crossbones from the Marvel comics. Ironically, the latter is a villain instead of a hero.
  • Sans's casual outfit is nearly identical to his appearance in Super Smash Bros. Ultimate.