Yachiyo Inugami, a 16-year-old top student in Class 1-A, embodies dog-like loyalty, boundless energy, and playful enthusiasm alongside a paradoxical love for cats. Her family life includes three pet dogs and a police officer father, inspiring her playful use of toy handcuffs. Academically excelling, she once ranked second nationally in middle school kendo but abandoned the sport when opponents hesitated to strike her due to her masochistic enjoyment of pain.

Outgoing and mischievously flirtatious, Yachiyo openly pursues girls—particularly her cat-like classmate Suzu Nekoyama, whose tsundere rebuffs thrill her. Their mutual attraction fuels comedic exchanges and physical teasing, with Yachiyo visiting Suzu’s Class 1-B during breaks to provoke affectionate scuffles. She relishes Suzu’s chastisement, fainting dramatically from a forehead kiss and craving punishments that "make her beg for more." Peers like Aki Hiiragi recognize their bond as romantic, dubbing their spats "lovers' quarrels."

Beyond this dynamic, Yachiyo befriends Mikine Nezu, whom she adores teasing for his cuteness, and Aki, who deadpans her antics. She avoids Yukiji Ushiwaka, discomforted by her presence. Though exuberant socially—her ponytail wagging like a tail during excitement—Yachiyo turns introspective when alone. Her journey consistently blends animal-themed humor with energetic school life and club pursuits, steadily deepening her romance with Suzu while showcasing her strong-willed yet masochistic spirit.