Since the day it was born, humanity had lived on the surface of the earth a life worse than death. The beings called the Abyss fed on it. They did not eat flesh. They ate the evil that men and women bred in one another, and every cruelty and every hatred made the Abyss stronger, until the hordes that served it had grown strong on the same wickedness. This went on for thousands of years.
The Abyss was no stranger from beyond the world. It was God's own creation, and God had left the whole matter of humanity, the Abyss and the earth to the Cycle, the great turning by which the world was meant to keep itself in balance. But the Abyss grew proud on what it fed on. In the end it grew strong enough to challenge God Himself.