Heretic

Three brothers known as the Serpent Riders have used their powerful magic to turn seven kings of Parthoris into mindless puppets and corrupt their armies. The Sidhe elves resist the Snake Riders' magic. The Serpent Riders therefore declared the Sidhe heretics and waged war against them. The Sidhe are forced to take a drastic measure to break the natural power of the kings and destroy them and their armies, but at the cost of weakening the power of the elves, which gives the Serpent Riders an advantage to kill the elders. While the Sidhe retreat, an elf sets out on a vendetta against the weakest of the three Serpent Riders, D'Sparil. He travels through the "City of the Damned," the destroyed capital of the Sidhe, then through the Maw of Hell, and finally to D'Sparil's dome.