The fallen human that fell into the underground. They were adopted by the Dreemurrs and Asriel is like their brother. They didn't have a good childhood before that point. They attempted to commit suicide but they survived the fall. (Yes, I am going to keep the gender ambiguous with the description change.) Well, that's all I got for you. Make a post if you feel like it. Heck, you can make headcanons on it. It doesn't change the fact. You can remix the character if you REALLY feel like it.