Sans and his brother Papyrus are skeletons, one day, showed up in the town of Snowdin out of nowhere in the Underground, a land below the surface of the Earth where monsters live. Unlike his flamboyant and loud brother, Sans is laid-back and pretty lazy. One day, a human child named Frisk showed up in the Underground. When they entered Snowdin for the first time, Sans was there to meet them. Sans told them about Papyrus, who hoped to capture a human to become a member of the Underground’s Royal Guard, and asked if Frisk would show themself to Papyrus just to make him happy to see a human. Frisk agreed, and while Papyrus didn’t capture them, Frisk befriended the skeleton brothers. However, Sans still hides several secrets and a large amount of power underneath his laziness, being the one who killed the sentient flower Flowey more times than any monster.