Mutsumi Serizawa is a second-year student at Jinnan High School and a member of the school’s Strings and Wind Club, where he plays the piano. He has black hair and dark brown eyes, and typically wears the Jinnan school uniform. In terms of personality, Mutsumi is kind, calm, and reserved, standing in contrast to his more outgoing friends. He is a quiet and observant individual who trusts those close to him and shows his thoughtfulness through small gestures, such as preparing tea for others. His reflective nature makes him a good listener and a dependable supporter of his peers. Motivated by a steady sense of loyalty and a desire to help, Mutsumi contributes to the club’s efforts without seeking the spotlight. His role in the story is that of a supportive ensemble member whose steady presence and musical dedication assist the group’s progress toward their goals. While his personal development is not heavily emphasized, he demonstrates a reliable and consistent character, with his piano skills serving as his primary notable ability. His interactions are marked by quiet cooperation and a calm demeanor that helps maintain harmony within the club.