Silverblood Scion - The Silverblood Series, #1

"You cannot command a demon unless you have struck a deal with it, and we have not yet struck such a deal." Elaine was meant to be the light for her people-the last of the Scions of Isa. But her goddess died long ago, and she is hunted for the inherent magic in her silver blood. After being condemned as a human sacrifice by Lord Dakin, a demon makes her a tempting counteroffer. If Elaine frees him from his prison, he will be hers to command. Demonlord Acies wants revenge just as much as he wants to escape from his prison cell.
Elaine could be the key, and she's a pretty one. But Acies' past haunts his present and the consequences of the war he once fought between gods and demons is never too far away. Wielding the power of demons can mean the difference between salvation and damnation . for both of them.