Miku Ahiru is a figure skating athlete affiliated with the Tonanmachi Lake Figure Skating Club. She appears in the series as a first-year middle school student who has been familiar with skating since early childhood but only began receiving formal coaching as a competitive athlete relatively recently. Her serious pursuit of the sport began after a reunion with her childhood acquaintance Kohei Kamogawa during a visit to her hometown. She has been described as a talented skater with a smooth and controlled skating style, known for her clean posture and precise movements down to her fingertips. Her greatest strength lies in her ability to skate with speed while appearing relaxed and flowing.

Miku’s personality is calm, serious, and responsible. She has a quiet and composed demeanor and displays a strong sense of duty, especially toward the people who support her. She is shown to be kind and approachable, helping younger skaters such as Inori Yuitsuka with schoolwork, and she maintains a friendship-like relationship with her coach and choreographer rather than a strictly formal one. She carries a deep awareness of her circumstances and the limitations imposed on her by external factors.

Her primary motivation is to make the most of her final opportunity to compete. The ice rink where she trains is set to close due to financial difficulties, which means she will no longer have a place to practice. As a result, the All-Japan Novice A championship becomes her first and last national competition. She decides to give it everything she has, carrying the hopes of herself, her coach Kohei, and her choreographer Juna Shiratori.

In the story, Miku serves as a notable rival and a parallel to the protagonist Inori Yuitsuka. While Inori is still building her career, Miku faces the end of hers. Miku’s arc highlights the harsh realities of competitive figure skating, particularly the impact of financial and environmental limitations on young athletes. Her role culminates in a poignant and emotionally charged performance at the national level, where she struggles under the immense pressure of skating immediately after the brilliant performance of the prodigy Hikaru Ouzaki. Despite her best efforts, she makes several mistakes during her free skate, falling short of her potential.

Her key relationships are with Kohei Kamogawa, her head coach and former childhood skating companion, and Juna Shiratori, her choreographer, who is also a former skater and close associate of Kohei. Both adults have known her since she was young, and they form a tight-knit trio within the club. Miku also interacts with Inori Yuitsuka, whom she treats with a gentle, older-sister-like attitude, offering guidance and encouragement.

Miku’s development follows her journey from a promising but untrained skater to a determined competitor who must come to terms with her forced retirement. She demonstrates growth in her ability to handle pressure, though ultimately the weight of the occasion and the brilliance of her rival prove overwhelming. Her story emphasizes the theme of choice: her decision to entrust her program to her coach and her acceptance of her own limitations become central to her arc. After the All-Japan Novice A, she retires from competitive skating as the rink closes, but she retains her connection to the sport and the people who supported her.

Notable abilities include her precise, elegant skating technique, her speed, and her ability to execute difficult jump configurations. Before her final competition, she achieved strong results, including a gold medal at the Hokkaido-Tohoku division tournament and a second-place finish in the national block rankings behind Suzuka Kamoto. She was referred to as the golden egg because of her latent promise, but her competitive career was cut short by forces beyond her control.