Movie
Description
Kosuzu Kachimachi is a student at Hasunosora Girls' High School, where she began as a first-year in the 104th class and later advanced to her second year. She grew up in the city of Tsuruga as the youngest child in a large household of ten, which includes her grandparents and cousins, and her family has a background in fishing. She decided to join the School Idol Club after developing a deep admiration for the upperclassman Sayaka Murano, and she became a member of the sub-unit DOLLCHESTRA.

Upon joining the club, Kosuzu initially appeared as a frazzled and panicked girl with extremely low self-esteem. She believed she had never accomplished anything of value and frequently made self-deprecating remarks, even suggesting that it would be better if she were not around. Despite these feelings, she possesses a persistent and hardworking nature. She is characterized as a challenge girl, someone who keeps trying and pushing forward regardless of repeated failures. Her catchphrase, used to psych herself up, is "chesto".

Kosuzu's primary motivation is to find something in herself that she can be proud of. Her admiration for Sayaka Murano drives her to work hard and get closer to that ideal. As she continues to struggle and grow, she comes to understand that her own efforts and perseverance can serve as a source of courage for other people. This realization becomes a new reason for her to keep challenging herself.

Within the story, Kosuzu represents the underdog and the emotional heart of her generation. Her journey from self-doubt to increased confidence is a central part of her character arc. In DOLLCHESTRA, a unit known for its serious and emotional songs, she contributes her earnest passion and determination.

Her key relationships include her strong bond with Sayaka Murano, who is both her inspiration and her upperclassman in the club. She also works closely with Tsuzuri Yugiri and forms connections with the other new members of the 104th class, such as Ginko Momose and Hime Anyoji.

Kosuzu develops significantly through her time as a school idol. She gradually overcomes her low self-esteem by learning that her value is not defined by her failures but by her persistent effort. She becomes more confident in her own abilities and more aware of the positive impact she can have on others.

Kosuzu does not rely on natural talent; her notable abilities stem from her relentless work ethic and refusal to give up. She practices tirelessly to improve her dancing and singing, compensating for her initial lack of experience through sheer determination. Her genuine and heartfelt approach to performances helps her connect with audiences.