Riki-Oh: Toukatsu Jigoku

A young man with extraordinary strength seeks vengeance against a yakuza boss for his girlfriend's death and is imprisoned in a high-security facility operated by a private organization. The prison consists of four sections, each controlled by a dominant inmate known collectively as the Gang of Four. The first is a knife-wielding, tattooed figure who governs his block using a mafia-style family structure. The second is a massive man possessing great physical power. The third is a flamboyant fighter cultivating opium within the prison. The fourth is a small individual who fights using sewing needles as weapons.