Good and evil, Heaven, Hell, and the Abyss. These three forces of ultimate destruction, tyranny, and righteous and benevolent good. This war an eternal struggle for dominance between the three forces. You are a servant of good in some way or another. Be it a creature born in the holy realms destined to protect it from intruders or a powerful angel battling demons, devils, and their ilk sword to sword.
Yet the battle for dominance lays in the hearts of sentient mortals. Those who choose the golden narrow path or the black and winding path. These beings who are able to display the brightest of souls or the blackest of hearts. Your charge is to vanquish those who choose the path of ruin and pain while protecting and guiding the innocent and the righteous. On the mortal plane is where you find yourself for whatever reason. It is on the mortal plane your greatest of foes now hunts.