Bound By Shadows by Vera Winters

Captured by the enemy. Bound to a cruel prince. Tempted by forbidden power.

Aric Solarian, battlemage and wielder of outlawed magic, falls into the clutches of the notorious demon prince Malekith. Now a prisoner in a deadly game, Aric finds his resolve tested and his darkest hungers awakened.
Malekith is as captivating as he is ruthless, drawing Aric into a web of sinister plots and forbidden magic. Even as Aric plots his escape, he is inexorably enticed by the demon’s magnetic pull.
As shadowy schemes unfold and the lines between enemies and allies blur, Aric must decide how far he’s willing to go to uncover the secrets of demon magic . . . and what he’s willing to sacrifice for a dangerous obsession that could destroy everything he’s ever fought for.