Zenichi Bunkyo possesses a violently aggressive nature and an intense hatred of being controlled. His path crossed Muon Nerima, a red-light district ringleader, following a confrontation where Zenichi refused payment to Ayaka Toshima and overpowered her bodyguards. Impressed by his defiance and strength, Nerima recruited Zenichi as a potential successor. As part of this arrangement, Zenichi wears an SCM device, earning one million yen for each person he successfully enslaves through SCM duels.

His aggression manifests when he encounters Shiori Adachi and Taiju Nakano. Learning Shiori is an SCM master, he challenges her to a "punching game," pummeling her face until she surrenders. He then assaults Nakano, believing them to be Shiori's slave.

After this, Zenichi is attacked by Zushioumaru, a dog wearing an SCM. The dog bites his genitals, forcing Zenichi to admit defeat in an impromptu duel, temporarily incapacitating him.

Despite setbacks, Zenichi steadfastly refuses submission. He rejects an offer to join Ryuuou Edogawa’s faction, declaring he would rather die than be subordinated, cementing his defining trait: an uncompromising resistance to external control.