KoKo Gurentai (2017)

With violent thugs eager to make a name for themselves, the cops ask undefeated high school gang leader Shota Hirose to skip town for a year. Shota leaves his own town to put an end to the violence between rival high schools. He returns after a year only to find things are worse.

Unfortunately the movie KoKo Gurentai is not yet available on HBO Max.