Hello there! So bare with me, new to the site and how everything is done here but we have an idea!

Angels/Demons/Humans.  

We are in a world of turmoil with demons and angels trying to co-exist while the human race is oblivious to the existence of these two races. Thousands of demons, angels and humans who have a demonic or angelic heritage (nephilim) begin to start competing to be a King candidate to become the 'anchor' of all three worlds, bringing them together to live harmoniously. Some might just want to take the easy route and start killing, others will be willing to actually work with everyone and create a council with the King candidate leading them all. 
It won't be all fun and games or smooth sailing. The constant fighting will attract unwanted attention from the human race, and there may be more occurring in the background than anyone has realised.
Power struggles, victories, losses, love, breaking the rules and making them up as we go along, who do you think will win? The possibilities and games are endless.