Sebastian is a rebellious loner who lives in his parents’ basement. He has jet black hair and black eyes, and commonly wears a black hoodie. He is Maru’s older half-brother. He tends to get deeply absorbed in his work, computer games, comic books, sci-fi novels, and will sometimes spend great lengths of time pursuing these hobbies alone in his room. He can be a bit unfriendly to people he doesn’t know.