Yanagi Uzaki is the youngest Uzaki sibling, currently in her second year of junior high school. She shares a close but mischievous dynamic with her older siblings Hana and Kiri, frequently teasing family members, especially during social gatherings involving alcohol. Yanagi enjoys orchestrating humorous situations, often manipulating scenarios to provoke playful banter between Hana and Shinichi Sakurai, sometimes involving her mother Tsuki as an unwitting participant. She exhibits a persistent enthusiasm for maintaining lively atmospheres, notably insisting on extending festivities at Shinichi's apartment even after her mother regains sobriety and attempts to conclude the evening.

Academically, Yanagi distinguishes herself as a high-achieving student within her family, contrasting with her siblings' performances. She excels at video games, surpassing Hana's abilities. Linguistically, Yanagi is the only sibling who retains the Kansai dialect taught by her father Fujio, as both Hana and Kiri eventually stopped using it. Physically, she shares a familial trait of sensitivity on the soles of her feet with her mother and sister. Her appearance includes distinctive bangs that consistently cover her eyes.

Professionally, Yanagi maintains a discreet occupation as an anonymous virtual streamer, adopting an elderly gentleman persona to deliver guidance while protecting her identity and privacy. This venture proves financially successful, generating substantial income that contributes significantly to household finances, a fact noted by her mother. Yanagi's introduction within the anime adaptation occurs in the second season; her voice is initially heard in episodes 14 and 16 before her official visual debut in episode 17.