Miyuki Onizuka, a junior high school student, lives at Hiten Shrine under the guardianship of her grandfather Tessai Onizuka, the shrine’s head priest. As a shrine priestess, she supports its daily rituals and spiritual operations. Tessai personally mentors protagonist Ryoko Mitsurugi in Hiten Style swordsmanship, emphasizing the bokken’s dual purpose as both a training implement and conduit for channeling spiritual energy.

Within the manga’s narrative, Miyuki appears sparingly, her role confined to reinforcing the shrine’s connection to Ryoko’s training. The anime adaptation offers modest expansion, showcasing brief interactions with Ryoko and visitors to the shrine, yet she remains peripheral to core storylines. No explored family history, personal motivations, or relationships beyond her grandfather are documented across official media, with no appearances in spin-offs or supplemental works.