Masaki Oosoto

Masaki Oosoto comes from a family of surgeons and is currently enrolled in a medical university, residing at Tasogare Inn as one of its guests. He presents himself as an intellectually refined gentleman with a composed and measured demeanor, and his sharp analytical mind once led him to assume the role of a detective assisting the protagonist Otoko Tsukahara in her investigation. Yet beneath this polished and mild-mannered exterior lies a hidden truth — he is, in reality, a serial killer. This duality makes him one of the most threatening and pivotal figures in the entire story.