Okay so I had idea for a semi small group idea, involving demons and humans.
There are seven demons who are based off the seven deadly sins, but they are not as glorified as the legends make them out to be. To enter hell or heaven you must navigate a labyrinth, this is supposed to test you and see where you are meant to go. The same goes for those trying to leave, but you see you aren't a loud to leave unless you are an angel that has been given permission or a soul whose life has not yet ended. That is where the seven demons come in, their task is to guard the labyrinth and make sure no one leaves. These demons are not the baddest or the bad or anything like that. Infact they are treated quite horribly and know one ever gives them credit for preventing the apocalypse from happening. Yes sometimes a few demons and tormented souls escape, and they always get severally punished for these mistakes.
These demons get tired of having to obey everyone and getting mistreated, so the leave the labyrinth and go to live human lives. Expect they know nothing about the human world so they find seven humans to live with and learn how to live in their world. Which is a small problem when heaven and hell find out that they are missing. Now all of thenafter life is after them to put them back within the labyrinth.
The humans are going to be playable characters and will some hwo be connected to another in one way or another. Each sin picks their human for one reason or another, maybe it is because they are attracted to their human, maybe it because a more dark reason, or maybe it is because they see this human has a possible friend. The humans don't know anything about the supernatural before all this so you can imagine the surprise they get when they find out they will be taking care of a demon and teaching how to live like a human.
Yeah this is kind what I had in mind, but it can be changed and improved upon.