Blackmantle

It is a time when the star-kingdom of Keltia is plagued by the Firvolgi, an ancient alien race. Yet along with a problem, the gods have sent a solution: Athyn Cahanagh, born orphaned on a battlefield, becomes High Queen and drives the invaders out. Athyn—now known as Blackmantle—and the great bard Morric Douglas fall in love and wed, ascending the Keltic throne as king and queen. But the lovely, dissolute courtesan Amzalsunea vows she would sooner kill her onetime lover Morric than see him with Athyn—and she keeps that vow. But Athyn has sworn an oath, too, one of love and vengeance; and taking the Low Road that only those mighty in magic may tread, she journeys to the Otherland, to find her lost lord and bring him home.