Movie
Description
Hazuki Katō is a student at Kitauji High School and a member of the school's concert band, where she plays the tuba. She is a classmate of Kumiko Oumae and Sapphire Kawashima, and the three form a close and enduring friendship. Hazuki entered high school with no prior musical experience; in middle school, she was a member of the tennis team, and she also practiced karate as a child. Her initial interest in joining the band was to play the trumpet, but she was ultimately assigned to the tuba, an instrument she affectionately nicknames "Chupacabra".

Physically, Hazuki has short, straight brown hair that curls slightly at the ends, which she often secures with a reddish-pink hair clip. She has gold-hazel eyes and stands 155 centimeters tall. Her skin has a healthy tan, a remnant of her days on the tennis team, and she has an athletic build. She prefers comfortable, sporty clothing like sweatshirts over more feminine attire such as skirts. Her favorite colors are orange and yellow, which she often incorporates into her personal belongings, including her shoes and school supplies.

Hazuki is best known for her consistently cheerful, friendly, and energetic personality, which makes her a beloved member of the band and a natural mood-maker. She is open and sincere, quickly becoming familiar with new people, as shown when she immediately asks her new classmate Kumiko to use first names. Her optimistic and positive attitude helps uplift the spirits of those around her, and she is a caring and supportive friend who readily offers empathy and encouragement. She is also somewhat spontaneous and can be clumsy, such as confusing different mouthpieces for instruments, but she always maintains a positive attitude and laughs at her own mistakes. Despite her outgoing nature, she is afraid of ghosts and scary stories, and she prefers reading shonen manga over shoujo, which she finds embarrassing.

Throughout her first year, Hazuki's primary motivation is to improve as a musician from her beginner status. Despite being a novice, her passion and perseverance allow her to discover the joy of playing the tuba. Early on, she is not selected for the main "A" team for competitions and instead supports from the B team, learning the value of backing up the main ensemble. However, her dedication to practice leads to significant improvement, and she eventually earns praise from more experienced members like Kumiko and Reina Kousaka. During this time, she also develops romantic feelings for their male classmate, Shuuichi Tsukamoto. She confesses her feelings to him at the Agata Festival but is gently rejected, as his heart belongs to Kumiko. Though hurt, Hazuki shows great emotional maturity by accepting this and choosing to support her friend's happiness.

As an upperclassman in her second and third years, Hazuki takes on greater responsibility within the band. Her skills have improved so much that Reina, known for being strict about musicianship, personally scouts her for a competitive ensemble. In her third year, she serves as the sub-leader of the bass section, working alongside Sapphire to guide and mentor new members. Her friendly and supportive nature helps integrate new students like Mayu Kuroe into the club, and she forms a close, teasing bond with her underclassmen in the tuba section, including Mirei and Satsuki Suzuki. By her final year, Hazuki has grown from a complete beginner into a competent and reliable senior, a respected figure whose energy and perseverance have become an example for others. Her journey culminates in her being selected to compete with the band in her final year, after which she decides to pursue a future in early childhood education, inspired by her ability to care for and support others.