The Darkangel.

Aeriel is kidnapped by the Darkangel, swept up into his dozens of black wings and carried to his distant keep. There she is to serve his brides - thirteen pitiful creatures who were once beautiful, before the Darkangel drained away their souls. Aeriel would free them, but now that she, too, is one of the Darkangel's captives, she can do no other than obey - even while she knows she must destroy him.

For when he has found his final bride, he will come fully into his sinister powers. Aeriel must kill him first, even though deep within him is a spark of goodness that makes her love him - a spark that could redeem even his evil.