Hassaku Hozumi works as a staff member at Studio Petit, where he collaborates with Mikiko Oguro to oversee animation production. His role involves managing the studio's unconventional animators, and he is known for offering pragmatic strategies to keep projects on track. He often relies on psychological tactics to optimize efficiency among the creative staff. In the first installment, for example, he advises deliberately provoking Aoi Fukami, a discontented housewife and animator, by referencing traditional gender roles. This method unintentionally accelerates her output by channeling her frustration into productivity.

In Animation Runner Kuromi 2, he continues to support the studio as it balances escalating workloads and tight deadlines. While he is less directly involved in the primary tension between maintaining quality and meeting schedules compared to other characters, his steady presence emphasizes his integral role in sustaining daily operations as the studio faces evolving challenges. He remains a consistent part of the team, often acting as a source of grounded, practical advice. His key relationship is with the protagonist, Mikiko Oguro, as they work directly together to manage production. The narrative confines his portrayal largely to these professional interactions, and the story offers little insight into his personal history or motivations beyond his duties at the studio. His notable ability lies in his understanding of the animation production process and his skill in applying psychological insights to manage a difficult team, using unconventional methods to solve problems and meet impossible deadlines.