He's a demon who used to be a demon slayer, he used to be the serpent hashira until he suddenly got offered to become a demon. So he did, he left everything behind, including his love, Mitsuri. He's now a malicious and cruel demon with long, black hair and black hands with sharp claws as his lower half is now that of a snake. He has infinite snakes but one of then is his favorite which is Kaburamaru, his friend snake who he had has as a human and still does as a demon.