The Warlock's Conquest. Shifters of Black Isle, #4

Revenge is the plan. until he meets one enemy he can't destroy. For six long years, Ferris has trained for a single purpose: avenge his sister and end the giant's threat once and for all. With deadly magic at his fingertips and a cut-throat crew at his command, the Black Isles are sure to fall. It's all so clear, until he starts to wonder if he's fighting for the wrong side. Eryn, the General's ruthless right hand, has one job: protect the Black Isles from the human invaders who would see them burn.
When Ferris's ship enters their waters, she's ready to strike first and hard. But the moment she faces him, something stops her blade cold. One heartbeat, one breath. and the warlock she should destroy becomes the one man she can't. They're sworn enemies, fighting for opposing teams in a war to end all wars. The battlefield is the last place where love should bloom. But as they are about to discover, passion and hate are two sides of the same coin.The Warlock's Conquest is the explosive conclusion to Lorelei Moone's Shifters of Black Isle series.
Magic, danger, and irresistible forbidden romance await-begin your journey properly with Book 1, Claimed by the King.