Dark Liaison — J.D. Brown

Ema Marx wishes her life would go back to normal, but there's nothing normal about being a Romani-Vampyre with an ancestor who wants you dead. Apollyon is back, wreaking havoc on the lives of everyone she cares about while plotting her demise.
Ema thought she would find a new best friend in her trainer, Bridget, until the exotic vampire vies for Jesu's attention. Jesu can date who he wants, right? Ema has more important things to worry about, like honing her powers. When Apollyon's thugs appear out of the shadows to attack her, Ema knows it's time to take action. But everyone else has other plans in mind.
One thing is for certain, being under house arrest in the German vampyre king's castle was not part of her plan to save the day.

Dark Liaison is the second book in the Ema Marx Series by J.D. Brown. Other books include:

Dark Heirloom (book 1)
Dark Liaison (book 2)
Athena's Oracle (book 2.5)