Yūki Asuhara attends Sakuragabuchi Academy as a first-year student, matching protagonist Nora Handa in age despite entering school a year later. Her gyaru-inspired appearance features long orange wavy hair with v-shaped bangs, typically tied in a ponytail, and amber eyes. She stands 160 cm tall with a slim build, pale skin, measurements of 86-54-82, and a distinctive fang. Her standard outfit includes the school uniform, knee-high socks, loafers, a flat cap, gloves, and a kemonomimi headband.

Born July 7 under the Cancer sign with blood type B, she maintains strong family bonds and notes all relatives enjoy good health. Energetic, friendly, honest, and hardworking, she juggles multiple part-time jobs—currently at a cat café where she often invites Nora during his feline transformations. She communicates openly in a casual, colloquial style using "Atashi" speech patterns, easily befriending others and putting them at ease. Though cheerful, she seriously contemplates her future, seeking Nora’s advice on career goals and expressing romantic aspirations.

As Nora’s childhood friend and underclassman, she acts as his confidante and integrates seamlessly into his social circle. She balances academics with work while remaining popular yet approachable among peers. Her involvement in Nora’s life includes adapting to supernatural events like Patricia’s arrival from the Netherworld and his shape-shifting, yet she stays grounded in everyday concerns such as job promotions and personal growth.