Yūgo Ōkami, a tall, large-framed second-year high school student with dark brown hair and brown eyes, wears a collared white long-sleeved shirt, black pants with a brown belt, and gray shoes. He is fiercely protective of his older sister, Nana, frequently checking on her at her apartment. This protectiveness manifests as concern and sometimes confrontational behavior when he perceives a threat to her, though Nana disapproves of these actions. His initial encounter with novelist Subaru Mikazuki was hostile, stemming from a mistaken belief that Subaru was harassing Nana, though this misunderstanding was cleared up.

Discovering Subaru authored his favorite series, *Shining in the Dark of Night*, caused Yūgo significant embarrassment. He formally apologized by visiting Subaru's home and kneeling in remorse upon entry. When Subaru dismissed the incident, Yūgo openly expressed his deep admiration for the novels, crediting them with giving him courage and pledging his ongoing support for Subaru's writing career. Sharing Nana's fondness for cats, Yūgo occasionally visits Subaru's residence to interact with the cat, Haru.