His Wicked Love by Mila Benson

As a warlock, Corbin trusts only himself and his master, Nereza. When that master is stolen from him by the kingdom that has long terrorized his kind, vengeance is the only answer. He has traded everything for the power to avenge her, and nothing will stop him. Being arrested is a minor setback. The paladin who arrested him is a bigger obstacle—but not even the heavily muscled, devastatingly gorgeous man who managed to slip past his defenses can keep him from his dark purpose.

Leonid, a paladin of Sithia, obeys the Archmage’s orders without question. It’s the least he can do to make up for his failures in the past. So when he stumbles on a warlock breaking into a Crown outpost, he doesn’t hesitate to arrest him. Between the warlock’s teasing touches, captivating eyes, and heart-stopping smile, it will be all Leonid can do to deliver him for judgment without yielding to temptation.

But all is not well in Sithia, and neither man can face the chaos alone. If they cannot learn to trust each other, neither will live long enough to see his mission completed.