"I'm a fallen angel"

Angels do exist. And they have their problems too. What problems? Try being locked on earth after falling while you tried to fight off a descendent of Satin. That is what happened to Athena and Lydia at least. They fell from heaven saving it. So to go back up they need to truly beat the demon that did to them. But until then they live in a large house in the middle of nowhere. That is, until the world needs some help...