The Obsidian Tower

From the Gemmell Award-shortlisted author of The Tethered Mage, The Obsidian Tower launches a bold new epic fantasy trilogy in which one woman's powers and choices may save - or destroy - a continent.
As the granddaughter of a Witch Lord of Vaskandar, Ryx was destined for power and prestige. But a childhood illness left her with broken magic that drains the life from anything she touches, and Vaskandar has no place for a mage with unusable powers. So Ryx has resigned herself to an isolated life as the warden of her grandmother's castle.
At the castle's heart lies a black tower. Sealed by magic, it guards a dangerous secret that has been contained for thousands of years. But when Ryx discovers a visiting envoy attempting to break into the tower, a magical accident leaves her with blood on her hands.
Unwittingly, Ryx has unleashed a threat that could engulf the whole continent. She and an unlikely collection of new-found allies must contain it, and the political conflicts that follow, or else everything she loves will fall to darkness.