The Lost Dragon (The Dragon Hunters #1‪)‬

Andreas was born a Spartan warrior, long before human history even records Sparta existing. He served directly under Ares, until the day his lover was killed on the battlefield in front of him. On that day, he met his father, the mysterious Black Dragon God known as Jarel. From then on, he served his father faithfully, enforcing the laws of the primordial embodiment of black fire and father of the paranormal. Now, in these modern times, he hunts the rogue vampires and their leader. Little does he know, there's more to this than vampires simply turning against his father. While protecting the lovely Cassandra Odele, Andreas must battle forces he doesn't know as he attempts to stop the resurrection of the Titan king, Cronus. Added to his problems, he now has two teenage nephews to see into adulthood. Of course, there's always a twist when dealing with the gods, and Andreas will come face to face with his past, leaving him to decide which is more important, his soul or the world?