Among Demons and Man, the Occult

The occult is a large group of humans and demons alike. Except there is trouble brewing between them and the death of an official in Satan's court has sent Gehenna on haywire. Now two unlikely heroes are sent to fix things before it sends the whole Assiah and Gehenna to the void. Will the two half brothers get along long enough to save both realms or will their quarreling end them.