Koji Kuroki

Kuroki is aggressive, impatient and more willing than the other Ha-Ha Brothers to fall back on street fighting when frustrated. His metal bat reinforces his early identity as a delinquent rather than an athlete.

He is also unexpectedly talented at games, including arcade games and simple skill competitions. That hand-eye coordination does not automatically make him a football expert, but it reveals that his abilities extend beyond fighting.

Like the rest of the trio, Kuroki initially resents being dragged into the Devil Bats. Repeated training and competition gradually give him pride in his position and in what the three can accomplish as linemen.

Kuroki begins with a 65 kg bench press and develops to approximately 85 kg as his football training progresses. His 5.1-second 40-yard dash gives him useful mobility for a lineman.

He plays on the offensive line and can also line up at linebacker on defense. His aggressive temperament translates naturally into contact, although football forces him to replace uncontrolled fighting with legal blocking and tackling technique.

The Ha-Ha Brothers become most effective when operating as a coordinated line unit. Their improvement comes through repeated physical training rather than extraordinary natural size.

Kuroki, Juumonji and Togano begin as delinquents who target Sena. Hiruma's intervention turns the situation against them and eventually forces all three into service as Deimon linemen.

At first they repeatedly search for ways to escape football. Their lack of experience makes serious opponents difficult to handle, but the humiliation of being dismissed as weak gradually becomes a stronger motivation than Hiruma's coercion.

The trio ultimately chooses to continue training of its own accord and develops into Deimon's regular line. Kuroki remains part of the unit through the team's increasingly difficult tournament campaign and its pursuit of the Christmas Bowl.

Erito Juumonji and Shozo Togano are Kuroki's closest companions. The three are almost always treated as a unit, although their individual personalities become clearer as they grow into football players.

Youichi Hiruma coerces Kuroki and his friends into joining Deimon and repeatedly prevents them from escaping their responsibilities.

Sena Kobayakawa is initially one of Kuroki's bullying targets. Their relationship changes as both become members of the same team.

Ryokan Kurita becomes the experienced lineman around whom Kuroki and the other beginners learn the physical demands of their position.