Kiaran by Hazel Hunter

The last escapee arrives, the final highlander meets his match, but time has run out for them both.
When falconer Kiaran Mag Raith’s kestrels find an unconscious woman on their morning hunt, he expects that she is for him. But unlike the other women who have become the mates of his clan brothers, her tattoo does not match his. Yet Kiaran dares to hope when he feels his cold heart stir for the first time in his long life.
Lillias must take the name that Kiaran bestows on her because she can’t remember her own. Nor does she have any memory of the underworld, the other ladies, or the handsome falconer. All she has is the ancient Pritani pendant she wears and an inexplicable feeling of dread.
But as Lillias and Kiaran draw closer to one another and the puzzle of who she is, Galan leads the Sluath to their doorstep. While the clan makes ready as best as they can, Cul, the castle’s ancient occupant, sees his centuries long plan come to its final fruition.