According to the feature of "little girl in purple clothes" given by you, I can give two figures that appeared in the history of the little devil fairy in Balala, both of which are in line with this feature:
Hanazono Sakura, a child prodigy in the magic fairy castle, is the protagonist in the rainbow heart stone of the little devil fairy in Balala, and his transformation clothes and uniforms are all purple dresses, as shown below:
Yan Lili: Balala.