Kiri Uzaki, the younger brother of Hana Uzaki, is a second-year high school student. He possesses distinctive silver hair and blue eyes in the manga, though his eye color appeared light brown during a brief first-season anime cameo before returning to blue in season two. His stature falls below the average height for a Japanese male, a frequent target for teasing by his sisters.

Contrasting his family's boisterous nature, Kiri presents as friendly, kind, sensitive, bashful, and innocent. He shares his sister Hana's passion for swimming and participates in the school's swimming club, though his athletic skills remain average, notably less pronounced than Hana's or Shinichi Sakurai's. He actively avoids video games with his younger sister Yanagi due to his struggles with them. A recurring theme is his expressed longing for a girlfriend, highlighting his romantic inexperience.

An encounter with Shinichi in a gym shower triggered significant insecurity about his physique, prompting him to seek advice from his father on exercises to increase his size, underscoring his self-consciousness about masculinity. Kiri develops a crush on Ami Asai, a fourth-year college student working at his sister's frequented café. This attraction connects to a deeper backstory: during middle school, a close friendship with a girl ended badly after he immaturely denied his feelings when teased by peers. This event fostered his subsequent desire to pursue relationships with women he perceives as mature, explaining his interest in Ami.

Within his family, he endures height-related teasing from Hana and Yanagi and shares moments of vulnerability about body image with his father. While appearing briefly in non-canon omake chapters, his first substantial story appearance occurs in Chapter 48 of the manga.