Tanith Lee

'A brilliant supernova in the SF firmament' Progressef'A beautiful writer ... the characters Lee has created are unique and brilliant' GuardianIn those days the world was flat, and demons dwelt beneath. They walked among the cities and kingdoms of the surface with power and mischief to please themselves. Among these demons were two who were mighty above all others: Azhrarn, Night's Master, and Uhlume, the lord of darkness, Death's Master.
DEATH'S MASTER is an epic fantasy of demons living among the ordinary inhabitants of Earth. It is a tale of superhuman feats and twisted ambitions - and of queens and witches, kings and commoners and the terrible realm of darkness.