The First Crime
Billy is a servant of the Kizaki household. He often trains Rio when her father isn't around, despite her father voicing his objection to it.
He is a very muscular bald African American man, who wears a shirt that says "Victory" with bandages wrapped around his hands. This with a black belt holding up his camouflage pants with combat boots.
He seems to greatly care for Rio, and is always willing to train her due to her great potential despite her father's protest. He is also very protective of the Kizaki Mansion, and will defend it at a moments notice. He also has a wife and daughter back in the states, and because of that stands up to Rio's father to let Rio be a hero, as he can't see how a father can deny his daughter her dream.
At some point Billy began teaching Rio how to fight.
First Crimes Arc
He is first seen training Rio, who was ecstatic she could train for as long as she wants because her father was gone from the house until morning. However her training is cut short when Big Mama stopped it, voicing how her father wishes for her to stop this and be more "Lady Like". Billy tried to defend Rio, claiming that she should be trained as their military already want to draft her despite her age, but Big Mama just told him to go back to the military and drags Rio off.
He reappears when Ratman broke into the house. He and Big Mama fought him off, where he delivered his Beat Fang attack to Ratman's jaw, who suddenly fled afterwards. Billy is last seen completely shocked that Ratman was able to take his attack and still be conscious.
Hero Awards Arc
After the hero awards, Billy is training Rio. After the training, Billy asks why Rio wants to get stronger and then listens to her reason.
Billy is called back to the United States to oversee his wife's operation. Before leaving, he and Rio both petition Shirouchirou to allow his daughter to get a Hero's License. After a sparring match between father and daughter and a promise for her not to die before he does, Rio finally obtains her dream to become a hero.
Billy is an excellent hand-to-hand combatant with extensive training in boxing.
- Billy the Beat Fang: A flurry of punches which ends in an incredibly powerful uppercut, which would most likely cause anyone below superhuman endurance to get knocked out instantly. As he showed surprise at the fact Ratman could still stand after he delivered the attack.
Billy is Rio's personal trainer. He does show some concern about her and does wish that her dream of becoming a hero does come true.
he is based on the real life person billy blanks