Live action TV
Description
Oscar, known in the original Japanese version as Narumi, is a secondary antagonist in the Riki-Oh story. Within the privately operated prison where the events take place, he is one of the four most powerful inmates, referred to as the Four Heavenly Kings, and he rules the North cell block. He is introduced as a fearsome, heavily tattooed figure who witnesses the protagonist's arrival and warns that trouble is coming, establishing him early on as a significant threat.

Oscar is brutal, theatrical, and intensely proud. He behaves as an enforcer of the prison's harsh order and treats the inmates under his authority with casual cruelty. His sense of honor is closely tied to his reputation, and he takes on the task assigned to him by the deputy warden with complete confidence when he is ordered to publicly execute the protagonist in order to discourage the other prisoners from rebelling. Even when he is clearly outmatched in a fight, he refuses to surrender or accept defeat.

His main motivation is to preserve his standing as one of the prison's ruling inmates and to prove his superiority through combat. In this role, he acts as an instrument of the prison administration, carrying out its orders against the newcomer who threatens the established order. His conflict with the protagonist is therefore both personal and institutional, and he represents the first major test of the protagonist's strength among the prison's elite fighters.

Oscar is a highly dangerous combatant. He attacks with an oversized saw blade and relies on raw aggression and overwhelming force rather than refined technique, which makes him a serious danger to ordinary inmates. His most distinctive trait is his extraordinary endurance and apparent indifference to pain. After being defeated in combat, he cuts open his own abdomen in a form of ritual suicide and, showing no signs of weakness, uses his own intestines as a weapon in a desperate attempt to strangle his opponent. This act demonstrates both his extreme tolerance for pain and the lengths to which his pride will drive him, and the protagonist is ultimately forced to kill him to end the attack.

Oscar's relationships are shaped by the violent hierarchy of the prison. He is willing to carry out the administration's orders, and he commands the inmates of his block. He also has a godson, a young inmate named Sa, who is devoted to him. After Oscar's death, the remaining members of the prison's ruling gang kill Sa when he refuses to take revenge against Oscar's killer, deepening the conflict between the protagonist and the prison authorities. Oscar's defeat marks an early turning point in the story, establishing the lethal stakes of the prison environment and setting the stage for the protagonist's larger struggle against the institution's corrupt leadership.