Who is Kerwick from The Wolf and the Dove and what is their importance?

Kerwick is Aislinn's betrothed. She notes that she had rejected many offers of marriage before her father becomes impatient and chooses for her. Kerwick is standing in the great hall when Aislinn is forced to choose between Wulfgar and Ragnor, and though she feels for Kerwick, she knows she can do nothing to help him through his current situation, because she is faced with the need for self-preservation. Kerwick eventually accepts that Aislinn belongs to Wulfgar and attempts to protect her when Ragnor kidnaps her. As the story ends, Kerwick seems enamored of Haylan.