The Mad Goblin — Philip Jose Farmer

They were known simply as the Nine - grim and ancient rulers who thirty thousand years ago had discovered the key to eternal life and ever since had secretly held the world in thrall.

Once, Doc Caliban had been their servant and had shared their secrets. Now, appalled by their tyranny, he has turned against them, daring to challenge their centuries-old supremacy. Together with two henchmen whose superhuman skills match his own, Caliban sets out on the trail of the deadliest of the Nine: the mad goblin Iwaldi, the very incarnation of evil...