OVA
Description
Kōta Oyamada is an orphaned high school student who moved from the countryside to the city after living with his grandfather. His parents' deaths leave his early family life largely undefined. Mild and indecisive by nature, he harbors a fear of swimming from a childhood near-drowning. Shortly after transferring to Kunpō High School, he meets Chizuru Minamoto, a centuries-old kitsune who declares romantic feelings for him. Her persistent public advances, often physically intimate, earn him school-wide nicknames like "Great Erotic King" and "beast" due to the resulting embarrassment.

Initially reluctant toward Chizuru's overtly sexual propositions, he forms a genuine emotional bond with her, enabling their fusion into a single powerful entity—a black-furred, five-tailed fox spirit. This transformation requires profound human-yōkai connection. In the manga, his fused form evolves further with fire-attributed tails linked to the "Eight Dragons," a power partially transferred from Chizuru, who wields its full scope as a nine-tailed fox. Their relationship deepens, culminating in marriage and a daughter. They formally adopt spirit-hunter twins Ren and Ai Nanao, who address them as parents.

His romantic life expands when he aids Nozomu Ezomori, a 200-year-old wolf spirit, during a dispute with a street vendor. Sensing her supernatural nature, he connects with her as she becomes Chizuru's rival for his affections. Prioritizing Chizuru while developing care for Nozomu, they achieve a polyamorous resolution where both become his lovers. Childhood pets include a dog named Pochi, a cat named Mike, and a goldfish named Yarkovsky. His water fear resurfaces narratively but he overcomes it to rescue another character from drowning.

Beyond romance, he bonds with Chizuru's adopted brother Tayura Minamoto, whose initial jealousy shifts to close familial friendship. Tamamo, Chizuru's foster mother and a powerful figure, initially doubts his suitability but tests his loyalty and willpower, eventually accepting him as a son. At school, he maintains a supportive friendship with class representative Akane Asahina despite her disapproval of Chizuru's behavior, and reconciles with former adversaries like sickle weasel spirit Omi Kiriyama. He navigates complex ties with figures including Yukihana—sent by Tamamo to test him—and Nozomu's brother Saku, who places a life-threatening seal on him due to distrust.

His character evolves from passivity to greater assertiveness in managing relationships and supernatural challenges, particularly in later manga arcs where he assumes familial responsibilities.