Composer for 'Nightcord at 25:00.' She is the composer for the circle. She was delighted to see Mafuyu reacting more to the songs she created, but one day, Mafuyu's mother demanded that she stay away from her daughter. Sensing something wrong in the mother's words and actions, she refused the demand and chose to stay by Mafuyu's side. She has a warm, deeply caring, and understanding personality.

Lyricist, Arranger, and Mixer for 'Nightcord at 25:00.' She is the lyricist for the circle. She lost her sense of self due to her mother's constant demands for her to be a 'good girl,' but through her music activities, she came to recognize the circle as a place where she belongs. When that sanctuary was threatened, she finally reached her limit, left home, and asked Kanade for help.

Illustrator for 'Nightcord at 25:00.' She is the illustrator for the circle. Despite suffering from what she perceives as a lack of talent, she possesses a strong heart that keeps her drawing even after receiving harsh criticism. She has a blunt personality and feels frustrated seeing Mafuyu unable to speak her mind to her mother, but she cherishes her as a teammate, noticing how much Mafuyu has changed since they first met. She has a very strong sense of pride.

MV Creator for 'Nightcord at 25:00.' She is the video creator for the circle. While worrying about Mafuyu's deteriorating relationship with her mother, Mizuki also felt a sense of helplessness regarding her own inability to face her secrets. However, through that experience, she realized that there are things to be gained by running away and advised Mafuyu that 'it's okay to run away.' She loves playing pranks but is also considerate and quick-witted. She shows deep concern and understanding for the emotionally cornered Mafuyu, and while she often teases Ena, she knows where to draw the line. Consequently, she usually plays the mediator whenever the blunt Mafuyu and the prideful Ena bicker.