So, one day God says to Joan, "I need you to change your name/get a really good fake ID and go to Miami." The name on her ID is Lumen Pierce.

I've never seen Joan of Arcadia, but I'm pretty sure that she was a nice and normal girl before god started talking to her. What if she wasn't? What if she was more like Dexter, only faking being normal, and holding off on her darker impulses as long as she could because if she could love anybody, she'd love her family?