Untamed Highlander (#4) by Donna Grant

DEVIL IN THE FLESH

Druid-born and magic blessed, Isla is one of the deadliest she-devils ever to serve the forces of darkness. As an immortal Highland warrior, it's up to Hayden Campbell to destroy her and her kind. But for Hayden, Isla is more then a sworn enemy. She is temptation...

ANGEL IN HIS ARMS

Taking Isla captive, Hayden hopes to avenge his kinsmen who died b y Druid magic. But when he looks into Isla's eyes, he sees the secrets of her past. When he touches her skin, he feels the passion in her soul. And soon, Hayden comes to realize that this beautiful,  beguiling woman is not his enemy at all- she is his destiny. And even as the forces of darkness conspire against them, their love will conquer all...