Ayane Shirakawa is a high school student with brown hair, distinctive aubergine-colored eyes, and stands 159 cm tall with an F-cup figure. Her favorite food is pudding. She is the older sister of Kotone Shirakawa, and both sisters share a childhood friendship with Kazushi Sudou, a university student.

Ayane demonstrates a strong focus on beauty and personal care, frequently saving her pocket money for specialized items like skin bath salts or lotions. Her personality features a characteristic "twitchy attitude" towards Kazushi, masking genuine concern and a struggle to articulate her feelings honestly. She often responds with outwardly irritable or defensive reactions that conceal her underlying affection.

Tension defines her relationship with Kazushi. A typical incident begins when he forgets to buy her promised pudding and then uses her special bath lotion without permission. In retaliation, Ayane impulsively joins him in the bath, bringing Kotone along. This act highlights her impulsive nature while subtly revealing her unresolved emotions towards Kazushi.