sans

sans is a skeleton monster and major character in Undertale. He appears lazy and humorous, but he watches the human's choices and understands more about timelines than most residents.

sans in UNDERTALE: identity and story role

Sans is relaxed, observant, secretive, and deeply tired by repeated resets. He uses teleportation, bone attacks, Gaster Blasters, gravity manipulation, and karmic damage during the genocide-route battle.

sans's relationships and major turning points

Papyrus is his beloved brother, while Toriel becomes a joke-sharing friend through a door. Sans avoids intervention in many routes, but extreme violence pushes him into the role of final judge.