Kaori Shiina stands as the central figure in her narrative, possessing both male and female genitalia, a physiological condition referenced within her story context as hermaphroditism. This biological aspect forms a core element of her character, treated as a career-threatening secret. Her physical appearance includes purple eyes, hip-length brown hair, and a feminine presentation often featuring elements like hair ribbons and dresses.

She works as a pop idol achieving rising fame, highlighted by a hit single and preparations for a concert tour. The opening theme song "Ai-iro Otome" connects to her character, featuring lyrics expressing loneliness and melancholy intertwined with hope. Her background reveals a life marked by isolation stemming from societal perceptions of her body. She actively avoided public attention before being discovered on a street by Yuko Imai, a former singer turned talent scout and manager drawn to Kaori's perceived uniqueness. Susceptible to affection due to prior loneliness and negative self-image, Kaori developed a romantic and sexual relationship with Yuko, who also became her protector regarding her secret. This relationship features significant power imbalances, coercion, and blurred consent, with Yuko often initiating sex despite Kaori's discomfort and leveraging her position as both manager and sole confidante.

Her career and relationship face a major challenge when Saki Midorisawa, a rival lesbian pop singer with a known history of pursuing women, targets Kaori. Saki discovers Kaori's secret by trapping her in a bathroom. Using this knowledge as leverage, she blackmails Kaori with an ultimatum: join Saki's group of lovers or face public exposure. This situation reveals a past connection; Saki and Yuko were formerly colleagues and lovers who endured sexual abuse from industry figures before Yuko abruptly left years earlier due to a vocal cord infection, abandoning Saki without explanation.

To resolve the blackmail, Saki proposes a sexual contest involving partner swapping: Saki paired with Kaori versus Yuko paired with Sayaka Tamura, competing to see which pair reaches orgasm first. Victory for Yuko and Kaori would secure Saki's silence. Yuko wins by utilizing knowledge of Sayaka's vulnerabilities, and Kaori manages to withhold her climax. Despite losing, Saki indicates she hasn't abandoned her interest in Kaori.

Throughout these events, Kaori's character development remains constrained. Her story primarily explores themes of exploitation, fetishization—particularly regarding her anatomy—and the vulnerability of marginalized individuals within exploitative systems. Her singing career and artistic expression, symbolized by her song, hint at a deeper emotional inner world, but her agency is persistently limited by the manipulation and desires of others like Yuko and Saki. Her identity is heavily filtered through the lens of the "phallic woman" fantasy, focusing on her penis as a source of fetishistic intrigue and narrative conflict, often overshadowing her personhood.