Is there a demon like this already?

[Yqatuba]

Is there a demon created from someone who was a child abuser in life? I was thinking of converting the rutterkin and making that their backstory.

[Coidzor]

As far as I'm aware, there's only Folca who is a Daemon.

Generally speaking, addressing child sexual abuse at the table is a very, very poor decision, so I would recommend reconsidering your plans if this is your goal.

[Zhangar]

Considering all the forms that child abuse can take (since it's pretty much just any evil conduct directed at a child), there really wouldn't be a single demon to cover it.

Incubi or succubi or schirs or vrocks or kalavakuses or andrazkus or even dretches could all work.

It's all just a matter of context.