Kazuo has a medium length, curly hair and a small beard on the chin. He has a very muscular physique. During the missions, he has no shame in appearing totally naked, or with the uniform up to the hips, due to his pervertly sexual nature.
Like most of the Osaka team, Kazuo is reckless and arrogant. Anzu describes him as a sex maniac who "fucks anything that has a wet hole," even raping female aliens during the missions. He is very dear to his students however, suggesting that he is gentle and charming, and only shows his true nature during the Gantz missions. Like the rest of the Osaka team, he takes drugs before and during the battle.
He is an English teacher who teaches children. At some point Kazuo died and was brought back by the Gantz and he became a veteran of the game, having won 100 points three times before the Nurarihyon Mission.
Nurarihyon Mission Arc
Kazuo, along with the members of his team, prepares for the hunt by taking drugs. To their surprise, they find another team in Tokyo, but ignore the implications of this by simply telling the Tokyo team to stay out of their way and not steal any of their points. He is next seen with his pants down, raping a female Alien with others of his team protecting him. Even trying to attack, but they end up being killed by one of them.
Then again, he is seen abusing another Alien, while his companions is assassinated by an Alien with face of bird. The Alien sees him fully engaged in the sexual act until the alien reveals his face, which irritated the other who attack Kazuo who uses the body of the other to defend himself. Kazuo was irritated that he was interrupted when he was enjoying himself. The Alien begins to attack him, but to deflect easily catching X-shotgun, but the alien runs away.
Together with Knob-yan and George, Kazuo tackles two of the most powerful aliens. Knob-yan declares that he'll kill one of them himself, and when the tables are turned, Kazuo and George refuse to help him, since Knob-yan declared he'd handle it himself. When Nurarihyon arrives, Kazuo and George work together to fight him. They destroy his first form, but he then transforms into a colossus composed of naked women, killing George in the process. Despite his better judgement, Kazuo cannot help himself, and fucks part of the alien's face. His arms and legs are sliced off, but he is saved from falling to his death by Masaru Katou, a member of the Tokyo team, who saves him and hands him off to Miho Yamanaka and Sumiko Yamada, two of his surviving team members, who flee the scene with him. As the Tokyo Team are fighting Nurarihyon in the distance, Kazuo asks Miho to fuck him.
Before Nurarihyon Alien Mission
Kazuo arriving to give class is well received by his students. They enter and the teacher begins the course. When you feel the call of Gantz, ask to go to the bathroom. He is then seen in the Gantz room with the other players, wearing the uniform up to the hips.
After Nurarihyon Alien Mission
After the Alien Nurarihyon Mission, he was seen naked in the Gantz room with the others who survived: Miho Yamanaka, Sumiko Yamada and Tsuneo Nikaido. The girls do not believe the others were exterminated and Kazuo says they should thank them for surviving and they reproach him for not having clothes. After the two chose to be free, Kazuo also chooses the one option: To be free and to lose the memory.
- In the film Gantz: O Kazuo scene's are cut because due to the amount of nudity and sex they would imply.
- Some think that he appears in Chapter 368, violating a Giant Alien, however it is worth remembering that Kazuo chose to be free to change from losing his memories.