From the introduction:
You must believe them. I have consulted old carvings, heard their whispers. What I write is truth... In their time of twilight, the old ones fled their dying lands. Powered by the blood of their slave race, they used fell magicks to travel between and behind the stars.
They arrived in this place in ancient days and lay claim to our steaming seas and heaving continents. The old ones raised great monuments of stone to pierce the heavens, and dug great mines to plumb the depths. They pulled from the gasping muck terrible beasts, each one the image of their creator writ horrid and massive. They used the blood of their slaves to give these great beasts life.
Aeons ere, wizards amongst the old ones had pierced the veil and discovered the great thirst that dwelled in the strange voids beyond. These wizards discovered the great powers on offer if that unkind thirst was slaked with sentient blood. Unwilling to offer their own lives, the old ones crafted their slave race, whose name in their own language is lost, but who I call the young ones.
The young ones were servants, toys, food, and power for their masters. The old ones used them, bred them, ate them, and bled them until the slaves’ wailings rent the heavens with grief.
The old ones had learned not the lessons of their motherland’s downfall and grew only more indolent and ever more cruel. Their slaves wept, cowered, hid, and learned.
After a long and terrible age had passed, the young ones finally rose up. They overthrew their masters and cast a ritual powered by the deaths of untold hosts of their own kind to banish the old ones forever into the strange voids beyond all ken.
A new epoch dawned.