The Egg of the Old Ones
Warlocks of the Great Old Ones bind themselves to beings outside of time and reality. They draw their power from the story of creation, the story of the Egg of the Old Ones, the story of the creation of Erathia.
The world is an egg. We will hatch it. Our Lord will be born.
In the cosmology of warlock cults, the world is a temporary shell housing of the Great Master. The mortal races are merely vermin, living on a shell, no more significant than pests or parasites, and just as worthless.
In the madness before creation, the greatest of the Old Ones reached the end of its life. As it died madness concentrated around it and our reality formed like a pearl.
The Great Master has been trapped ever since, growing in strength, waiting to be reborn.
Over millenia, they performed the rituals and made the sacrifices to try to release the thing inside the world. None of their attempts ever worked until the Kirinal Catastrophes made a 10-mile hole in the crust of the world. Suddenly, warocks grew in numbers and powers. Their rituals become more powerful. The Dead of Kirinal were the perfect sacrifice. The warlocks eventually summoned the Host of the Far Realm to Erathia to crack open the world and release the Great Master.
The initial strike of the Far Realm was meant to crack open the world, but it was deflected and resulted in the Shattered Moon. The war to drive away the army of aberrations lasted for 25 years before the Far Realm was defeated. The god Naraky performed his final trick, Naraky's Eggs.
In a mirror of his first trick, he exchanged the contents of the World Egg with a hen's egg and beyond the Divine Gate, chased by the Elder Evils. The gods followed behind and closed the Gate behind them, trapping themselves outside of reality with the Elder Evils and ending the threat to their creation.