Gurin, alias Chinpei Hatsuyama, serves as the mechanic within the four-member Phantom Thief Tonchinkan, a group composed of a kung-fu master, a psychic, their junior high teacher, and Chinpei himself. His technical expertise supports the team’s operations, which begin as parodic heists targeting worthless objects. The group issues calling cards to mock traditional phantom thief tropes, executing low-stakes thefts with minimal collateral damage while evading Inspector Dokuoni’s dogged pursuit.

As the story pivots to focus on slice-of-life humor at Reinbou Junior High, Chinpei’s role expands beyond gadgetry to include participation in the school’s absurd antics and chaotic mishaps. The team navigates their teacher’s eccentricities and leverages their individual skills to manage comedic clashes with Dokuoni, often employing creative tactics to sidestep his efforts. While episodic gag-driven narratives dominate, Chinpei’s personal history and character development receive limited exploration in official sources. Extended media adaptations, including spin-offs, films, or OVAs, do not feature his character in documented materials.