Natsuki Nakagawa is a second-year student at Kitauji High School who plays the euphonium in the concert band. She began playing the instrument in high school after being inspired by her classmate Nozomi Kasaki. Natsuki is easily recognized by her distinctive ponytail and often comes across as sarcastic, easygoing, and sometimes indifferent. Early on, she tended to lack motivation and would frequently skip practice, but as the series progresses she begins to practice earnestly and becomes more dedicated to the band. Despite not being selected for the competition ensemble, she acts as a supportive and responsible upperclassman to the younger members. Natsuki develops a particularly close, mentor-like bond with her junior Kumiko Oumae, and she also shares strong friendships with Yuuko Yoshikawa and Hazuki Katou, often lightening the mood with her humorous teasing. Her personality balances a friendly, mature, and calm demeanor with a subtle wit. She is understanding of others and tends to accept situations with composure. Over time, Natsuki grows from an unmotivated student into a reliable vice president of the concert band, showing a deeper commitment to music and the group’s success. While she may struggle with self-doubt regarding her abilities, her loyalty and sense of responsibility drive her development. Natsuki’s primary skill is her proficiency on the euphonium, and her growth reflects a broader personal transformation toward confidence and leadership.