Shinobu Handa's formative childhood moment occurred in a park, sharing biscuits with Momoko Naitou, who kissed her in return. This created a profound, lasting bond for Shinobu, though Momoko later forgot the incident. Years later, both attended Kagome Academy, an all-girls school, where Shinobu hoped Momoko would recall their shared past and promise.

Shinobu embodies wealth and privilege as a carefree only child, displaying disregard for rules and academic effort. She consistently arrives late to class, sleeps during lessons, and maintains failing grades, earning a delinquent reputation, despite indications she was once a model student. She freely uses the school's poetry club room as her personal sanctuary.

Physically, Shinobu has orange hair, green eyes, and stands 1.69 meters tall. Her personality is bold and mischievous, including exhibitionist tendencies like intentionally exposing her underwear to classmates. Popular due to her sexual charisma, she participates in a dormitory-based "harem" with multiple female partners. While sexually active with many, her deepest affection remains reserved for Momoko, anchored by the memory of their childhood kiss and her attraction to Momoko's distinctive perfume.

Shinobu's relationships are complex. Her closest companion is Kirin Suwabe, whom she treats in a servant-like manner; their interactions include sleeping together and sharing intimate moments like morning kisses. Another pivotal relationship begins when Maya Enjoji kisses Shinobu during a nap. Shinobu responds by seducing Maya, who becomes devoted to her. Shinobu encourages Maya's transformation from submissive to more assertive, albeit with increased perversity. Following graduation, Shinobu, Momoko, and Maya form a committed three-way relationship, living together. Shinobu also provides romantic advice, such as guiding Shigure Komai toward accepting her younger sister's incestuous feelings.

A significant conflict arises with scheming upperclassman Sayuri Ookami, who desires Shinobu exclusively. Sayuri manipulates situations hoping to get Momoko expelled, prompting Momoko to violently retaliate. This initially separates Momoko from the school, but Shinobu and Momoko eventually reconcile and consummate their relationship months later.

Beyond school, Shinobu remains popular in her workplace, attracting persistent advances from female coworkers attempting to kiss or seduce her. Her adult life maintains the established polyamorous structure, continuing the relationship with both Momoko and Maya.