Keiji is a tall man with a muscular build. He has short fluffy bleached blond hair and gray eyes with dark circles underneath. He wears a long-sleeved gray shirt with rolled-up sleeves, a black vest, brown pants, and black dress shoes. Being a participant in the Death Game, he wears a collar as do all Participants, Dummies, and Floor Masters. Keiji is a man with a certain darkness in his heart. He keeps a laid-back, relaxed attitude to establish himself as a figure of authority and claims to be a policeman despite resigning years ago. Coming from a police force background, Keiji has a realistic, up-to-earth worldview, prioritizing his survival foremost. Keiji shows his cynicism by refusing to see the dummies as people, such as putting down Rio Ranger for being a doll and upfront telling Ranmaru that he is not a person. Driven by the fear for his life, Keiji makes harsh decisions, such as sacrificing Kanna for a chance to escape. Despite his actions being foremost self-serving, he comes to care about Sara, in whom he sees himself in many aspects. He guides the girl and encourages her to lead the group by herself, often putting too much responsibility on her shoulders.