Castor is an old, immortal spirit who takes the physical form resembling a skeleton. He was originally a human, many, many years ago, until he was cursed after selling his soul to a demon, he was given immortality which was what he wanted but at a cost, he was stripped away of his humanity, causing everyone to fear him. He forgot about his family, friends, and majority of his past life, so he remains hidden away in an old mansion, his old home, being one of the last things he remembers.