Her Demon Lord

I'm really bad at describing things. Please don't let my rubbish explanation stop you from reading! The Demon Lord is looking for a wife. Carlenes parents want her to 'apply' for it. For the safety of the world, of course. Carly's mum is a fallen angel, so they feel they can get all the useful information to counter the attacks. But maybe it's not a wise idea, Carly's parent used to be an angel but she's not anymore, Carlene has nothing to do with heaven, why should she help them?