A member of the Kitauji High School wind ensemble. Her instrument is the euphonium. She often wears her long brown hair in a ponytail. She is bright and friendly, but a bit lazy and moves at her own pace. She observes people's emotions and the surrounding atmosphere closely, and sometimes blurts out what she's thinking. While continuing in the band, she begins to think about what she truly wants from music. She is best friends with Reina Kousaka and childhood friends with Shuichi Tsukamoto. She is by no means a caustic character and interacts with others brightly.

A member of the Kitauji High School wind ensemble. Her instrument is the trumpet. She has long black hair and a dignified aura. She is extremely stoic and never compromises when it comes to music. She has clear goals and ideals, strongly desiring to become a "special existence." While usually calm and mature, she shows her emotions honestly in front of Kumiko. She has high performance skills and spares no effort. She is exceptionally close to Kumiko.

A first-year student in the Kitauji High School wind ensemble. Her instrument is the euphonium. She is petite, characterized by a cute atmosphere and a red ribbon. She understands her own charm well and excels at acting like a "cute junior." While she is sociable and friendly toward seniors, she observes people and situations closely, possessing a sharpness that reads between the lines. She is not the type to show her true heart easily, hiding complex emotions behind her cute demeanor. She is particularly attached to Kumiko and treats her familiarly. She harbors wariness toward Mayu Kuroe. She also has a side that is weak to pressure. She takes her euphonium practice seriously.

A senior member of the Kitauji High School wind ensemble. Her instrument is the trumpet. She is petite and emotionally expressive. She has a very passionate personality and can get emotional for the sake of her friends or juniors. She cares deeply about the members, especially admiring Kaori Nakaseko. She is at odds with Natsuki Nakagawa and they often argue, but in reality, they understand each other well. She has a strong sense of responsibility and takes club activities seriously.

A senior member of the Kitauji High School wind ensemble. Her instrument is the euphonium. She has a bright, frank personality and is very caring. While she usually seems aloof, she watches her juniors closely and cannot leave someone in trouble alone. She is at odds with Yuko Yoshikawa and they often bicker when they meet, yet they acknowledge each other. She treats her juniors, like Kumiko, in a friendly manner.

A member of the Kitauji High School wind ensemble. His instrument is the trombone. He is Kumiko's childhood friend. He is mild-mannered, caring, and the type others rely on. He can talk easily with Kumiko and understands her well. In the band club, he practices seriously as a male member. He and Kumiko have a relationship where they can speak their minds without reservation, though he occasionally shows complex emotions.

Hails from the Tohoku region and speaks in standard Japanese. A game streamer with an image based on the color blue. He is bright, talkative, and generally high-energy. He handles both the straight man and the funny man roles, but often gets carried away and escalates situations himself. He doesn't mind being treated roughly by those around him and often turns it into a joke. He is characterized by quick situational judgment and fast reactions cultivated through game streaming. In school life, he teases the band members or causes silly commotions with his streamer friends. In serious moments, he is surprisingly observant.

Speaks in a Kansai regional drawl and often makes jokes or light remarks with a nonchalant attitude. He excels at making himself the butt of the joke or acting silly on purpose. While he usually seems irresponsible, he observes the surrounding situation and human relationships closely. He often watches noisy comrades like Koneshima from a step back. In serious situations, he reads the room and acts accordingly. Kumiko and the others think of him as "someone who is somewhat hard to pin down."

Speaks in a Kansai regional drawl. He is free-spirited and loves pranks or anything that looks interesting. Because he suddenly starts doing strange things or teases others, people are sometimes wary of him. However, he doesn't necessarily have malicious intent; he often does things simply because they seem fun. In games, he is the type to act boldly while enjoying the situation. Even in serious moments, he has unique ideas. He is particularly close to friends like Shaorong.