Yukari Kamishiro is the vice-homeroom teacher and music instructor for Yūto Ayase's class at Hakujō Academy. Students know her informally as the "sexual harassment teacher" because she teases troublemakers and engages in provocative behavior, especially when drunk. She always wears a smile but displays a playful and unrestrained personality outside the classroom. Though 23 years old, she frequently claims to be "eternally seventeen." She actively expresses a strong desire for a boyfriend yet remains unmarried.

Her long-standing friendship with Ruko Ayase, Yūto's older sister, leads her to spend considerable time at the Ayase home, often drinking heavily with Ruko. During these gatherings, she commonly becomes inebriated, sometimes disrobing and making unwanted advances toward Yūto, contributing to household chaos and messiness. This conduct reinforces her nickname and highlights her lack of inhibition under alcohol's influence.

Speculation about her past persists, with rumors suggesting she might be the "Performer of the Sunset," a distinguished music figure who graduated from Hakujō Academy. This possibility gains credence when Shiina Amamiya, a transfer student and accomplished pianist, cites the rumored teacher's presence as her reason for choosing the school. While not definitively confirmed, this potential connection remains a persistent element of her background.

Physically, she has blonde hair typically styled in braids and green eyes. She stands 1.63 meters tall, with measurements of 89-56-87, and has blood type A. Her overall demeanor and actions, like crashing parties and prioritizing fun, align her more with a "disco girl" image than a conventional teacher.