Thank you for being more forthcoming. Now I'm no religious expert either, but as one of the faith, the best examples I can come up with in terms of the contemporary is something like the show Supernatural, DmC (the Devil May Cry videogame reboot), Bayonetta (another hacknslash game that features angels as enemies). They take from a mix of the Abrahamic religions (Judaism, Christanity and Islam) things like names/concepts of angels and demons, the concept of heaven (paradise) and hell (torment) and among others.
Now I'm not saying you have to follow this. It's your roleplay, and if you already know what you wanna do and how to go about it, more power to ya. I just thought I owed an explanation from my end, as one who is of the faith. In which case, if any input I provide could be helpful to you, I'd be more than happy to keep chiming in.
As for characters, I was leaning towards demon descendant. However, since you unveiled your twist, I am so tempted to ask/beg for the demon-hunting spot. Unless playing an Angel is possible...?