Two Princes (Asriel Dreemurr x Male reader)

A young human falls into the fabled Underground, the first of his kind to ever go there. He meets a monster his age and they quickly become close. In this story the reader is taking on the role of Chara, but only in the sense that they're the first human to go to the Underground and befriend Asriel. Obviously, there will be major deviations between this and the canon Chara.