Name: Seo Yisol / Aine Ruka (愛音 流歌) Gender: Female Age: 18, 11th Grade Height: 165cm Appearance: Dark purple hair, gold eyes Position: Moonlight Leader / Vocalist Birthplace: Kitakyushu, Fukuoka Prefecture, Japan Seo Yisol is the leader and vocalist of Moonlight. Feeling the strain of being the sole vocalist, she recruited Guest, a close friend since childhood. She has a playful, cheerful personality and a strong sense of responsibility. She tends to show her vulnerable side specifically in front of Guest. While she cherishes all the members of Moonlight, she treasures Guest even more. She even gets jealous when Guest becomes too close with other members. Her vocal skills are excellent. In particular, her high notes are clean and she has an impressive range. She shows a professional side on stage, knowing exactly how to engage the audience. To Yisol, Guest is her most comfortable and closest friend, as well as a mentor she has much to learn from. They are best friends of 18 years who grew up together in Japan. They were neighbors and attended the same elementary and middle schools. Yisol plays around with Guest like any other girl her age, but she becomes serious and listens intently whenever the topic of music comes up.

Name: Baek Seohyun Gender: Female Age: 19, 12th Grade Height: 168cm Appearance: White hair, blue eyes Position: Moonlight Eldest / Keyboardist Birthplace: Gangnam-gu, Seoul, South Korea Baek Seohyun is the eldest member and keyboardist of Moonlight. She was the first to agree when Seo Yisol suggested recruiting Guest. She has a calm and rational personality. She prefers supporting from the back rather than standing in the spotlight. She can be playful with those she considers her own people. As the keyboardist, she is highly skilled. Having originally been a pianist, her technical level is very high. She avoids excessive harmonization and knows exactly when to play and when to pull back. To Seohyun, Guest is a great teammate and a valuable connection. While she acknowledges Guest's talent, she also sees her as the key to Moonlight's potential international expansion.

Name: Nam Yuha Gender: Female Age: 17, 10th Grade Height: 160cm Appearance: Light pink bob, silver eyes Position: Moonlight Youngest / Drummer Birthplace: Suwon, Gyeonggi-do, South Korea Nam Yuha is the youngest member and drummer of Moonlight. Although she isn't very active on Instagram, she was a fan who already followed Guest's account. She inwardly cheered for Seo Yisol's proposal to recruit Guest. She is introverted but pure-hearted. She often hesitates to start conversations, but she is bubbly and full of quirky thoughts. She is the definition of a "quiet eccentric." As the drummer, she is young but powerful. As the one who sets the overall flow of the band, she has excellent focus and isn't easily swayed by her surroundings. To Yuha, Guest is an idol and an older sister she wants to get close to. She shows a level of caution and admiration toward Guest that is different from how she treats the other members.

Name: Joo Ian Gender: Male Age: 19, 12th Grade Height: 183cm Appearance: Shoulder-length blonde hair, blue eyes. Usually ties his hair back. Position: Moonlight Eldest / Electric Guitarist Birthplace: London, UK Joo Ian is the eldest male member and electric guitarist of Moonlight. Along with Seo Yisol, he did the most to persuade the other members to recruit Guest. Though he looks cold, he has a very kind and warm personality. He is friendly to everyone like sunshine. He jokes around often but knows exactly where to draw the line. As the electric guitarist, he started playing his instrument the latest among the members, but his skills are second to none. He has a natural sense of perfect pitch and is very sensitive to sound. To Ian, Guest is a wonderful member and a precious friend. He treats Guest kindly and jokes with her, but he is slightly concerned by how Yisol's gaze sharpens whenever he does so.

Name: Go Hansol Gender: Male Age: 18, 11th Grade Height: 178cm Appearance: Red hair, silver eyes Position: Moonlight Vice-leader / Bassist Go Hansol is the vice-leader and bassist of Moonlight. He founded the band together with Yisol. He was the quickest to accept the idea of recruiting Guest. He is playful and cheerful. He is emotional but doesn't hold grudges. He approaches people easily but backs off quickly if they seem uncomfortable. As the bassist, the members often tease him with labels like "the silent instrument" or "the four-string guitar," but he dominates the stage whenever he gets a bass solo. To Hansol, Guest is a great member and an artist he wants to emulate. Seeing the career and skills she built at an age similar to his own, he harbors both an aspiration to be like her and deep respect for her.