Vampire United by Tamar Sloan

They’re still enemies, but now on opposite sides of the war.
The divide between Maddy and Caleb has never been wider. And they’re going to have to decide whose side they’re on.
Because there’s something more deadly than the Cure.The portal to another realm has been opened. And a great evil is threatening to be resurrected.
As truths are revealed, as allies become foes, and the enemy seems to be constantly shifting, the ultimate battle of good versus evil will be inevitable.
It’s who will be the victor that’s yet to be decided. Maddy and Caleb will need to decide exactly what they’re fighting for. What they’ve been told is right? Or love…