Nekonoshin Matatabe acts as a henchman for the antagonist Unkokusai within the film's narrative. He presents a fiercely intimidating physical appearance and is constantly attended by two women within Unkokusai's domain. His combat style relies on wielding twin swords, reserving one specifically for emergencies. He consistently speaks using a distinct first-person narrative pattern and deliriously boasts about his professional accomplishments. Matatabe performs pivotal actions, including assassinating Fubukimaru's mother during Unkokusai's military campaigns. While pursuing the protagonists, he battles Fubukimaru and the Nohara family, initially overpowering Fubukimaru by wearing him down through exhaustion tactics. His defeat comes when Shinnosuke Nohara uses the "Save3X" transformation to become a cockroach, enabling Fubukimaru to launch a decisive counterattack that removes him from the conflict. The narrative offers no confirmation regarding his survival or human origins beyond this confrontation.