Armageddon (in the bible) is the final war between Heaven and Hell right? And the outcome will determine the fate of the world.
What if when you (now I dont know how armageddon and such work in FfH) trigger this war, and every civ has to be on a side, except maybe the neutrals. And every civ gets it's share of the Angels/Demons, and if you triggered the Armageddon and you win the war, you have won the game?