Blue-Blooded Vamp: Sabina Kane: Book 5 by Jaye Wells
Sabina Kane is on the hunt. Her prey is Cain, father of the vampire race and the madman whose obsession with the goddess Lilith fuels his murderous plots. Armed with the name of a sect of dark historians who know the location of Cain's lair, Sabina sets out for Italy. But she finds much more than she bargained for when the leader of the sect turns out to be someone who shouldn't be alive, much less leading a band of militant academics. But she doesn't have time for shock or arguing with her obstinate ally, because it's going to take every weapon - both mundane and magical - to win the fight of her life.