Anzai started participating in dogfights at a young age. He won his first victory over Yoshimura's tosa with his dog, Unryu. After the official fight, Anzai meets Yoshimura when he's walking his dogs. Yoshimura's puppy Zero attacks Unryu, but Unryū is too strong for him and he's nearly killed. Unryū then fights Yoshimura's tosa and kills it. Anzai keeps training Unryū to make him bigger, stronger and more evil. He practises Unryū's moves on straydogs, which is the reason why Unryū ends up killing Zero's mother.