TV-Series
Description
Nozomi Kasaki is a second-year student at Kitauji High School and a flute player in the school's concert band. She first appears in Sound! Euphonium 2 as a former member who left the band during her first year due to a conflict between the first-year and third-year members. Her return to the band forms a central conflict early in the season, particularly because of the impact her departure had on her closest friend, Mizore Yoroizuka.

In middle school, Nozomi attended Minami Middle School, where she served as the president of the wind ensemble club. She was an accomplished and charismatic leader who noticed Mizore, a quiet and unsociable classmate, and invited her to join the club. Nozomi frequently talked with Mizore, walked to and from school with her, and introduced her to the world of wind ensemble music. Together, they set the goal of advancing to the national competition in their final middle school contest, but after choosing an overly difficult piece, they earned only a silver award. This disappointment strengthened Nozomi's determination to reach nationals in high school.

Upon entering Kitauji High School, however, she became disillusioned with the club's internal dysfunction and ended up quitting alongside many other first-year members. This decision deeply affected Mizore, who continued playing as an oboist but felt abandoned. Nozomi later attended the Kyoto competition and was impressed by the band's new, focused direction under conductor Noboru Taki. She then expressed a desire to rejoin, which created tension among the band members, especially those who had been hurt by the mass exit. With the help of second-year trumpet player Yuko Yoshikawa and the mediation of Natsuki Nakagawa, Nozomi reconciled with Mizore and was allowed back into the band after the Kansai competition.

Personality-wise, Nozomi is cheerful, optimistic, and outgoing. She easily connects with others and is often seen as a source of positivity and enthusiasm within the band. Her lively spirit and love for music make her an inspiring presence among her peers, and her juniors affectionately call her Nozo-senpai. Beneath this bright exterior, however, Nozomi carries guilt over leaving Mizore and a complex mixture of affection, jealousy, and possessiveness toward her. Her motivations are rooted in a deep desire to make up for past mistakes and to achieve the musical excellence she always strived for, both for herself and for the band.

Within the story, Nozomi serves as a catalyst for exploring themes of friendship, regret, and forgiveness. Her return forces the band to confront lingering grudges from the previous year, and her evolving relationship with Mizore is a major emotional arc. She also serves as the band's treasurer after rejoining and becomes the flute soloist in the A section. She performs wholeheartedly and helps unify the flute section with her friendly nature.

Key relationships include her intense bond with Mizore Yoroizuka, which is characterized by mutual admiration but also by a painful history of abandonment and reconciliation. Nozomi is the person who first brought Mizore into music, and their bond is tested when Nozomi quits and later when they both prepare for music university entrance exams, leading to further strain. Nozomi shares a close, friendly relationship with Natsuki Nakagawa, who acts as an intermediary during her return. She holds admiration and a hint of rivalry toward Reina Kousaka, and she also confides in Kumiko Oumae after her withdrawal, finding common ground in their shared passion for music.

Notable abilities include her excellent flute technique, honed from years of practice since middle school. She is a natural leader, having been club president in middle school and later taking on organizational responsibilities as treasurer in high school. Her performance skills are strong enough to earn her the flute soloist position in the A competition ensemble. She also shows emotional growth over the course of the series, learning to communicate more openly and to prioritize the harmony of the group over her own previous status.