does this character sound good, evil or ambiguous? can you understand her actions?

That sounds like a really interesting concept. Presuming that you want her to come across as sympathetic, I think that her intentions should be clear and that should be implied in the way you write it.

I would see her sympathetically if she's doing this to help her child out of necessity, even if she thinks that it is wrong. Maybe she could only bring him evil people to feed on? Though that might risk becoming a little boring or Anne Rice-ish. I quite like some of the suggestions above me.