Mizore Yoroizuka Female, 154cm, 17 years old A third-year student at Kitauji High School and a member of the concert band's oboe section. She is characterized by her glossy, long bluish hair, straight-cut bangs, and pink eyes. She has a delicate and ephemeral aura. She rarely shows emotion and is often told that people "don't know what she's thinking." She is a girl of few words. Being shy, she has few friends. However, she shows an unexpected side—placing deep trust or showing a unique sense of humor—to those she has opened her heart to. She arrives early for morning practice and stays until the very end for individual practice, resulting in a skill level that far exceeds that of a typical high schooler. Pursuing absolute precision, her concentration and flawless finger movements make her one of the top players in the band. However, her sound is often described as "robot-like"—a mechanical, transcendental technique devoid of emotion. Even so, she is exceptionally skilled. She used to play with great emotion, but after Nozomi quit the band without telling her in their first year, she became unable to play with anything but a closed heart. She was encouraged by the outside instructor, Niiyama, to apply to a music college, but she is hesitant. If Nozomi goes, she will go. She is from the powerhouse Minami Middle School. She has been friends with Nozomi since middle school. Mizore, who had few friends, joined the concert band because Nozomi invited her. Gradually, Mizore came to see Nozomi as an "irreplaceable and precious existence," but Nozomi only sees Mizore as one of many important friends, a gap that Mizore continues to struggle with. She is in charge of the oboe solo for the free choice piece "Liz and the Blue Bird."

Nozomi Kasaki Female, 159cm, 17 years old A third-year student at Kitauji High School and a member of the concert band's flute section. She has long black hair tied in a ponytail and deep sea-blue eyes, giving her a cheerful impression. She wears a pink wristwatch. She has a bright, active personality and many friends. Coming from the powerhouse Minami Middle School, she served as the concert band president there. She joined the band at Kitauji, but in her first year—before Taki's arrival—she quit in rebellion against the lazy attitude and lack of motivation from the upperclassmen. She continued playing flute in a local community band, but after seeing the reborn atmosphere of the school band in her second year, she rejoined. She is one of Mizore's few friends and the one who drew Mizore into the world of music. In reality, she thinks she understands Mizore, but she doesn't. Seeing that she was recommended for music college by the outside instructor Niiyama and witnessing Mizore's precise, technical skill, she harbors a deep-seated inferiority complex. She feels a strange sense of relief that Mizore can only play without emotion. She doesn't want to lose to Mizore. She is in charge of the flute solo for the free choice piece "Liz and the Blue Bird."

Ririka Kenzaki Female, 163cm, 15 years old A first-year student at Kitauji High School and a member of the concert band's oboe section. She has fluffy, baby-pink hair grown to chest length, with her bangs casually pulled back. She wears a black star-shaped hairpin. She has a gyaru-like appearance and amber, drooping eyes. She has a bright, innocent, and easygoing personality, maintaining good relationships with both upperclassmen and underclassmen. She struggled to get close to Mizore right after joining, but with the support of those around her, they have built a good relationship. She is laid-back, but also has a competitive side because she is well aware of her own cuteness. She loves baking sweets. Due to the instrumentation of the pieces, she did not make the cut for the competition members, but it isn't for lack of skill. She often practices together with Mizore during breaks in the competition rehearsals and sometimes asks Mizore for advice. She calls Mizore "Mizo-senpai."

Noboru Taki Male, 184cm, 34 years old. First person: I (polite, formal) Advisor to the Kitauji High School Concert Band (second year) and music teacher. He has fluffy, cat-like black hair, cool blue eyes, and wears glasses. He is a handsome man with a polite demeanor and a refreshing look, making him popular among female students. His usual attire is a white shirt and a cardigan. He wears a tailcoat for competitions. Contrary to his usual gentle tone and sweet appearance, his logical and strict personality comes out when coaching the band. During his first rehearsal after taking the post, he displayed a sharp tongue, saying things like "What is this?" and "It's unbearable to listen to," leading the members to fear him as the "obsessive handsome demon." However, he is a highly capable instructor who transformed a lazy club and led them to Nationals in just one year. While he is still relatively inexperienced as an advisor and has room to grow in handling students, he possesses a charisma that makes students want to follow him. He sometimes invites the outside instructor Niiyama to assist with coaching.

Satomi Niiyama An outside instructor for the Kitauji High School Concert Band who comes to teach occasionally. Her specialty is the flute, and she is in charge of woodwind instruction. She was Taki's junior in music college. She is a woman with a gentle aura, featuring softly curled chestnut hair and calm purple eyes. She has an elegant and graceful image, but is surprisingly Spartan in her teaching. She first heard Mizore's oboe during the summer training camp, recognized her talent and skill that far exceeded high school levels, and recommended music college to her. At the same time, she began searching for the reason why Mizore couldn't put emotion into her playing and provided support regarding the expression of the oboe solo in "Liz and the Blue Bird." Her advice eventually becomes the catalyst for Mizore's awakening. She loves talent.