Legend has it that many, many thousands of years ago, the gods were but mortal men and women, like all of us. These men and women performed great deeds of heroism, and eventually became legends. The legends gave way to mythic undertakings as the Great Heroes in time ascended the Celestial Stairs and became gods.
In time, other men and women, jealous of the apotheosis of the gods, sought their own pathways to power and glory. Not all of these roads were walked in the light; many contacted the Ancient Ones through dream-magic and blood rituals, selling their souls and the souls and lives of innocents in their quest for godhood.
The Ancient Ones--their names make men shudder, women wail, and children hide shivering in horror. The Ancient Ones--Azathoth, Yog-Sothoth, Shub-Niggurath, Hastur, Nyarlathotep, and their kin, their legions led by their high priest and cousin, Great Cthulhu. It is said that the Ancient Ones made humans and our kin, as slaves, playthings, and food. But scholars claim some sort of arcane cosmic cataclysm occurred that shifted the stars in the sky, stars by which the Ancient Ones drew energy for their very vital essence.
With the shifting of the stars, the worst of the Ancient Ones fell into a deep torpor. The country of Great Cthulhu sank beneath the ocean. And yet still they spoke to those who served them, in dreams, portents, and dark writings containing forbidden secrets that drove men mad. And gradually, the dark power of the cults grew, and the worst happened: the Ancient Ones stirred in their eternal slumber.
The gods mobilized, and bringing great power to bear, they went to war. Most sided against the Ancient Ones--some turned traitor and stood with the dark cults. The world was torn asunder as eldritch energies were thrown, and great cataclysms shook the land to its core, creating rivers of lava, new oceans, destroying continents and raising new ones.
In the end, the Ancient Ones' legions were defeated, the dark powers driven back to torpor, and the gods retreated back to the heavens. In the aftermath, they left the secrets of magic and crafting for men, and scattered throughout the world were twenty one great Swords of Power, lost during the wars.
The world is now born anew, born of fire and bathed in blood, and a new breed of heroes takes up the call to tame the Wasted Lands and carve a place once again for humans and their kin to claim dominance over the world. Mayhap these new heroes will become the next generation of gods...but many will perish in the undertaking.