Pursued By Peril by Lindsay Buroker

The dragons of the Cosmic Realms aren’t pleased now that Azerdash has recovered a legendary galaxy blade. It makes him more of a threat in his quest to oust their kind from power. To stop him, the dragons have sent one of their own after him, a deadly assassin who likes a challenge…
Arwen wants to help Azerdash, but she has her own problems. She must track down the missing vampire alchemist, Zoltan. It’s her fault that he was kidnapped, and she can’t leave him in the hands of dark elves.
But when the dragon assassin comes after her, because of her relationship with Azerdash, Arwen must worry about far more than kidnappers.