She is both a hard worker and a character who gets teased, as well as the straight man. According to her, she apparently dislikes being teased, but no one else pays any attention to that, making her a pitiable girl.
Somewhat mentally unstable.

She is cheerful and practically the mood maker. Although her true identity is a machine, she is so precisely made that you would never notice it just by looking at her normally. She can also switch between her machine form and human form at will. Somewhat mentally unstable.

She is the leader and loves pranks. A flawless leader, she often gets into verbal fights with Chinatsu, but Yu almost always wins. She is said to be on bad terms with Chinatsu, often making her cry on streams and frequently bringing her to tears. But despite everything, they get along well.
Somewhat yandere.