Yuuko Tsurumaki teaches at Chidori High School and volunteers as faculty advisor for the reinstated Rifle Shooting Club. She assumed this role upon discovering the club needed supervision for competitions, seeking ways to connect with students. Her appearance includes long brown hair, golden brown eyes, and distinctive orange rectangular glasses missing the upper frame. She typically wears a beige cardigan over a white collared shirt.

Personality-wise, Yuuko exhibits absent-mindedness and frequent self-critique, openly questioning her teaching abilities during class and feeling distracted during lessons. She lives in an apartment densely packed with anime merchandise like DVDs, limited-edition figures, and PVC statues, cluttering the space to the point of impeding movement, defining her as an otaku.

Her interactions with the Rifle Shooting Club include expressing romantic interest, stating she has "three years to decide which of the members to choose." She blushed when student Izumi Shibusawa remarked she likes Yuuko "just as she is," prompting Yuuko to immediately clarify she cannot engage in such relationships with students. This dynamic led club member Hikari Kokura to humorously suggest Yuuko is pursuing a "harem route." Yuuko holds a gold-star driving license but rarely drives. To fulfill her advisory duties, she researched the club's history and activities.