The Last Aerie (Necroscope: Vampire World Trilogy)

Nestor and Nathan Kiklu are the twin sons of Harry Keogh, the Necroscope. United by blood, they also share some of their father's awesome powers--but what they do with those gifts cannot be more different!

Nathan takes up the struggle against the metamorphic vampires, while Nestor, fascinated by the vampires' eerie evil, has become his twin's worst nightmare: a Wamphyri Lord!

Harry Keogh's sons have become the bitterest of enemies, each determined to destroy the other. When next they meet, one will surely die!