Mitsuo is one of the two protagonists of Tokyo Zombie, a horror-comedy manga originally serialized in the late 1990s and later adapted into a live‑action film. He works as a blue‑collar employee at a fire extinguisher factory alongside his best friend Fujio. The two are slackers who spend their lunch breaks training in jiu‑jitsu, dreaming of becoming famous martial arts champions overseas. Mitsuo is depicted as a former jiu‑jitsu champion with genuine skill, yet he is also a bumbling, lovable moron who rarely takes life seriously.

His motivations are simple: enjoy his friendship with Fujio, improve his jiu‑jitsu, and ideally escape their mundane factory job. When the pair accidentally kill their abusive boss, they dump the body at Black Fuji, a toxic garbage mountain. The industrial waste reanimates the dead, triggering a zombie apocalypse. Mitsuo’s role in the story is that of the slightly more capable fighter of the duo, though his impulsiveness often leads to trouble. During the chaos, he becomes infatuated with a young woman at a convenience store and attempts to rescue her, but is bitten by a zombie. Convinced he will turn, he leaps off a bridge into a river, disappearing from Fujio’s life.

Years later, Tokyo has become a feudal society where the rich stage gladiator‑style fights between zombies and enslaved humans. Mitsuo reappears as one of the combatants, having survived the fall and somehow avoided fully turning. He is reunited with Fujio inside the arena, and the two fight together using the jiu‑jitsu skills they once honed. His development shows a shift from carefree dreamer to hardened survivor, though he retains his loyal and slightly reckless nature. His most notable ability is his jiu‑jitsu expertise, which he both used in training before the outbreak and later relied on to survive the zombie‑infested world. His relationship with Fujio is the emotional core of the story, marked by brotherly camaraderie and a shared determination to reunite.