- Complete Monster: Marcus Black is the sadistic, psychopathic father of Mercury Black. He was an Atlas soldier who joined solely to kill people. He was disgraced and discharged after an assault on Vacuo. He later became an alcoholic assassin who sometimes tortured his victims for his own entertainment and sometimes for extra pay. He regularly beat his wife, Melanie, and beat Mercury mostly out anger and sadism. When Melanie only wanted him to eat dinner before abruptly leaving for a job, he beat her after she decided to argue with him about it and took Mercury with him. On that job, the target had his daughter with him and he held her at gunpoint with the intent to kill simply because she was a witness. First, he forced Mercury to kill her father right in front of her, despite his own son's protests to at least kill her first so she didn't have to watch her father die. After living in the mountains, Mercury finally snaps at Marcus and calls him a horrible father and a disgrace of a soldier. This prompts him to ruthlessly attempt to murder his own son " free of charge". He never cared one bit about his family and did many horrible things without remorse.
- Jerkass Woobie: As much of a sadistic sociopath that Mercury became on the show (and later in CRME), Looking at his home life in this story can't help but make you feel bad for him. His father is abusive to both him and his mother. And while his mother suffers the same abuse, she only responds by passing it along to him.
YMMV / The Black Hearts