Chara Dreemurr is the last human that fell in Underground before the protagonist, adopted after they fell from the surface by Asgore and Toriel. They live in Snowdin with their brother Asriel, and play a supporting role in the story. You encounter them in the beginning of Snowdin. They take the role of Sans. They are gender natural, but it doesn't matter how you see them. In DEVILOVANIA (A StoryShift FanGame), by Insult Goat Bro, is a female however.

They don't have 1 ATK and 1 DEF like Sans do