Every 1000 years, gods of every pantheon convene and hold a conference to decide the fate of humanity by calling a vote to determine whether or not the human race should continue living or go extinct. With the most recent of these conferences having concluded, the gods unanimously decided to put humanity to an end. However, at the very last second, the youngest of the Valkyries, accompanied by the child of her eldest sister, intervened and made the bold proposition to let humanity have a say in their fate by letting them go against the gods in a series of one-on-one fights for a second time to see if they are worthy of continuing to exist. As their pride shattered, the gods accept the proposal. Thirteen gods will fight against thirteen human champions. The first side to reach seven victories will decide humanity's fate.
Ominous prophecies and dreams had long foretold the downfall of the cosmos and of its gods and goddesses along with it. It isn't until Volva, a Seeress, foresees the event's of Ragnarok unfold.
The three roosters will crow, in Jotunheim, the hall of Valhalla, and in Hel. The horns will sound across the skies of the Nine Realms. Snow and ice will freeze the world. Mountains will crack. Fenrir's fetters will be no more. The skies will turn black.
But... it had already begun long before.
The gods will meet their fate. They won't be around to hear your final prayer.