Bloodline Betrayal

Elias, a top vampire hunter, rescues Caleb as a brother. But Caleb is a pureblood vampire prince who has searched for Elias for centuries. He manipulates Elias, eliminates everyone close to him, and finally turns Elias into a vampire, imprisoning him. When Elias stabs him with a holy nail, Caleb sacrifices himself to lift the curse. Years later, a boy identical to Caleb appears, starting the cycle again.