Master operates Cafe Nowhere, serving as the office for the Hamatora detective agency. He maintains a reserved demeanor, typically found methodically grinding coffee beans behind the counter and offering minimal responses, though he occasionally dispenses surprising wisdom. His quiet care manifests in relationships, particularly his serious observation of Hajime despite an initial impression of indifference. He shares a complex history with Moral, initially feigning ignorance of their connection before later revelations about their shared past.

Physically, Master possesses light brown skin, a muscular build, and a bald head accented by a white beard. He wears black square-framed glasses, a tight white button-down shirt, black suspenders, and black pants. His shoes remain unseen, as he never leaves the counter area. A star-shaped mark on his head becomes visible later.

His background reveals he was once a scientist at Facultus Academy. Witnessing Hajime's Minimum ability, he believed she deserved better treatment, directly opposing Doktor's intent to kill her. Moral supported keeping Hajime alive, enabling Master to resign and found Cafe Nowhere. He then provided refuge at the cafe for Hajime and another test subject, Koneko. This past underscores his underlying compassion and sense of responsibility.

Minor traits include his dislike for Nice sitting without permission, reflecting his emphasis on propriety within his space. He consistently fulfills requests from Hajime and others for food preparation, though this occurs off-screen.