A Man Betrayed — J.V. Jones

At Castle Harvell demented Prince Kylock grabs the reins of power and hate by murdering his father. Harvell's two young refugees are torn apart by the storms of war:
Headstrong young Melliandra is captured by brutal slavers and Jack, whose wild power works miracles, falls prey to a smuggler's lying charms and a woman's seductive schemes. Meanwhile, in the distant stronghold of Bren, Kylock's betrothed, beautiful, mad Catherine, dabbles with darkest sorceries.

A knight's shattered destiny is about to lead from death-sport pits to the blood-strewn creation of an empire--and a wondrous epic of grandeur and magic continues...