Alright. I knew it was kind of cliche, and I probably didn't do a good job of averting it from being so. That being said, it was mostly to just get some ideas out and it will probably undergo revision. Like for instance, I could have the Demon Hunter arrive and slaughter the other demon/save the girl as opposed to him merely deciding to let her live. As for how her parents hid her when they couldn't see the demons it could be argued that they merely thought they were just general thugs coming after them for some reason or another. I could definitely flesh it out and that might lessen the cliche. I could also remove the part of it being related to her birth father and go with the idea that her adoptive father had accrued gambling debts with a certain group of men who just so happened to also be demons.
Alternatively, I do have a few other ideas brewing and while I doubt you're the type to deny a character simply because you dislike them or something I am interested in creating a dynamic character who could add to the story in a meaningful way so if you'd like to see the other ideas I have, I'm also open to explore those options a bit if you think it'd make for a better character.