The Dreamers #1: The Elder Gods by David Eddings, Leigh Eddings

Now, as the Elder Gods are about to transfer their power to the Younger Gods, the Vlagh plans to take advantage of their weakened state and neutralize them, eventually conquering the world. To do so, it is breeding a terrible force borne of monsters and demons. But one ray of hope shines through the darkness: four children called the Dreamers. They alone hold the power to change the course of history . . . and stop the Vlagh in its quest for total world domination.