The Hybrid Rule by Quinn Loftis

So many impossibly powerful foes have opposed the wolves and their allies over the years. Evil witches, warlocks, fae, elves, and alphas, just to name a few. And all have found the pack too strong to break. But the foe hellbent on taking down the pack now—the vampire king, Cain—has a plan that might finally tip the balance of power away from the wolves.
In the middle of the desert, Cain works desperately to find a way to mix the blood of wolves and vampires. While most find the idea reprehensible, Cain believes it is the key to his victory. He imagines an army of unstoppable hybrids with the combined power of the vampires and the Canis lupus. Such a force would be unstoppable, even for the powerful of alpha of alphas, Fane Lupei. And Cain just might have found the secret ingredient necessary to bring his plans to fruition.