Oc/Reader is female and Stain's biological Daughter.

She is in the same age group as class 1A.

Her mother died giving birth to her.

Her quirk is Bloodbending (she can have waterbending as well if you want)

She has no idea that her dad goes out and kills "Unworthy" heros.

She has always wondered what her dad would go out and do, sometimes coming home with blood stains.

So one day she follows her dad and is horrified to see her dad attacking a hero and going to kill him(ingenium) she stoped her dad using her quirk before taking the injured hero away.

(Tensei isn't paralyisied But his arm Is injured so badly he can't use his quirk)