Millie Nowya is her full name btw.
Mille was abandoned when she was just a child. She had her older sister taking care of her after she took her with her when running away. She had met her parents, but has no memory of them since she was basically kidnapped by her sister at such a young age. Even though her sister had basically kidnapped her, she does not think of it in that way and more or so thinks about it as her sister "saving her from the horros that she had to go through" which, more or so, are lies - not entirely though. The times that her sister would be out "working", Millie would be out playing with her friends. Mille was mainly cared for by her friends while her sister was out and about.
MiL's lore mainly aligns with Ray since they are friends. She is also currently an adult (mid 20s)