Enemy Embrace — Patti O'Shea

This is a novella that was originally published in 2011 as part of the Crave the Night anthology.

Nicole Ruiz is an elite vampire hunter who can shadow her quarry anywhere. Daktan is an executioner assigned by the demon king to eliminate a rogue vampire who's killing humans. When Nicole discovers the rogue is stronger than she expected, she offers Dak an alliance. She'd make a deal with the devil himself if that's what it took to avenge her family.