Valetudo

Valetudo is a superpowered human, with no intention of being directly involved in heroism, but will occasionally be called upon if Callisto is involved and needs help. He has an abusive, controlling mother, and a father who passed when he was 10. Valetudo often suspects his mother killed his father. Valetudo is a pyrokinetic, he can start and throw fires from his body, and he's immune to flames hurting him. His mother is also pyrokinetic, but he thinks she can do more than that. She's seemingly very powerful and seems to be able to anticipate anything. He's tried to hurt her many times, and has given up attempting pre-meditated attacks.

Valetudo was kept underground for all his life, giving him extremely pale skin. He only went outside when it was to fulfill his mother's plans, which he was forced into, often by violence and threats, and he's killed a lot of people since he was a boy, just to avoid being hurt anymore. His body is covered in large scars from his mother, and the occasional mishap on these violent excursions. He was randomly taken out of this lifestyle by Callisto, who sacrificed himself just to get close, and got burned in the process. Valetudo feels bad about this for a long time after, but Callisto never brings it up.

Ready to give up, he allowed himself to be put in a cold prison, waiting for his mother to locate him and inevitably kill everyone just to get to him, but Callisto shows up and reveals he can block her from Valetudo, and brings Valetudo into his life. It doesn't take long, but once Callisto shows his affection, Valetudo falls for him too, and becomes incredibly loyal. Some time later, he goes with Callisto to NYC and tries to fit in, later having to confront his mother for the final time and putting that part of his life behind him.

Valetudo is a quiet, literal, and serious person, he's not loud about his thoughts or feelings, but he's always wanted to be safe and keep others safe, and does his best to keep his life once he has it.