Miyuki Nonogusa is a student at the academy and a member of the school swim team, having joined during her sophomore year. She possesses notable swimming talent, which becomes a source of envy among fellow swim team members, particularly team captain Shinobu Kobayashi. Nonogusa has brown hair styled in a bob cut with spiky bangs, brown eyes, a slim build, and a pale complexion. She is typically seen in her school uniform or a one-piece swimsuit during team activities. Nonogusa exhibits a delicate, submissive, and shy personality, traits that make her vulnerable to bullying. She was previously in the same high school class as Taki Minase, who participated in bullying her by derogatorily calling her "Nogusa" (a crude reference to defecating outside). This victimization continues within the swim team environment. Her primary narrative centers on her victimization by swim team captain Shinobu Kobayashi and Kobayashi's accomplice, Mikimoto. In one incident, Kobayashi confronts Nonogusa in an empty classroom or locker room, accusing her of arrogance after being selected to represent the school at a swim meet instead of Kobayashi. When Nonogusa refuses to quit the team, Kobayashi and Mikimoto physically assault her, tie her hands and feet with tape, gag her with a sock, and violate her using a vibrator. They photograph the assault and insert a deodorant spray bottle into her anus, threatening to release the photos unless she leaves the team. In an alternative version, Nonogusa is cornered in the pool locker room by Kobayashi and Mikimoto, who tie her up and cover her mouth with duct tape before harassing her and cutting apart her swimsuit with a knife. The situation escalates when Mika Ito and her boyfriend arrive. Ito removes Nonogusa's gag, and Mikimoto forces Nonogusa to perform oral sex on Ito's boyfriend, who then takes her virginity. This is followed by a group encounter involving Kobayashi, Mikimoto, and Ito, during which Nonogusa eventually stops resisting and succumbs to the coercion. After this assault, Nonogusa is seen in the nurse's office, where school nurse Reika Kitami repeatedly rapes her while scolding her for failing to protect her virginity. The aftermath varies depending on interactions with Taki Minase. If Minase exploits the situation, he offers to retrieve the incriminating photos from Kobayashi in exchange for sexual favors from Nonogusa. She agrees, and after they engage in sex, Minase provides her with some but not all of the photos. Later, under Kitami's control, Nonogusa participates in Minase's torment in the pool locker room, revealing she knew he withheld photos. She anally violates him with a double-headed vibrator and administers aphrodisiac injections until he dies from exhaustion. If Minase assists her without exploitation, he retrieves all the photos and warns Kobayashi and Mikimoto to leave Nonogusa alone. Grateful, she becomes the new swim team captain and rescues Minase when Kobayashi and Mikimoto attack him, knocking them out with a kickboard and helping him dress while promising secrecy about the incident. In another storyline, Minase uses the photos to coerce Nonogusa, Kobayashi, and Mikimoto into an art room orgy. Nonogusa pleads with Minase to avoid violent treatment and thanks him when he rapes her instead of allowing another student to violate her. She experiences pleasure during the encounter but begs him not to ejaculate inside her. Nonogusa also appears in the OVA series "Bible Black: Only," Volume 1. In this segment, Mika Ito and her boyfriend witness Kobayashi and Mikimoto abusing Nonogusa in the locker room. Ito and her boyfriend join the assault, resulting in a group encounter where Nonogusa is again victimized.