Sebastian is a rebellious loner who lives in his parents’ basement. He is Maru’s older half-brother, and feels like his sister gets all the attention and adoration, while he is left to rot in the dark. 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.