This is Arima, she's a human, not a catgirl -- The cat tail and ears are just accessories. This is her when she was 11 years old in Middle School. She was getting bullied because she looked 'cute' and 'like an anime girl' so the girls in her classes put her in this outfit to make fun of her. She, later on, she grew up and went to an expensive princess school to learn new things and get a good-paying job for the future. She promised herself she'd never make any more friends in High School, but she quickly broke that promise after a few months of School.