Shuu Inuzuka is a first-year high school student and Yuu Izumi's best friend. He sports short, spiky blonde hair, orange eyes, and a fair complexion. Preferring a casual style, he wears his school uniform without a tie, typically pairing the white shirt with gray pants and white sneakers.

Outwardly happy-go-lucky and supportive, especially as Izumi's dedicated "wing man" for the relationship with Shikimori, Inuzuka reveals a responsible side through his commitment to multiple part-time jobs. He diligently saves money toward his long-term ambition of becoming a veterinary doctor. He maintains a friendly rapport with Shikimori's friends, Kyou Nekozaki and Yui Hachimitsu, who often call him by the nickname "Inu," meaning "dog."

One of his jobs is at a coffee shop alongside Rika Isana. He admires Isana, who respects his determination and work ethic and aspires to own her own shop someday. Initially, Inuzuka mistakenly believes Shikimori dislikes him, seeing her as a rival for Izumi's attention. This perception is inaccurate; Shikimori actually respects him and subconsciously views him as a brotherly figure, partly due to his resemblance to her older brother.

His dedication to work consumes much of his free time, limiting his availability for casual socializing outside of school. This choice reflects his prioritization of future aspirations over immediate leisure.