Dark Harmony- Laura Thalassa

"For Callypso Lillis, the fae magic that now runs through her veins is equal parts curse and good fortune. For the very thing that bonds her to Desmond Flynn, the King of the Night, also makes her vulnerable to the Thief of Souls, a man who wants to break the world--and Callie along with it. But it's not just the Thief whose shadow looms over the Otherworld. Des's father is back from the dead, and he wants revenge on the son who sent him to the grave in the first place"--Back cover.

Book #4 Bargainer Series