Wolfsbane Moon by Donald Scott

Across centuries and continents, an ancient evil stalks the shadows, feeding on blood, fear, and the secrets buried within history. When elite assassin Stephen Prower becomes entangled in a deadly conspiracy, he is drawn onto a collision course with Ivalyo Chilikov, a man carrying a dark legacy that has endured for seven hundred years. As brutal killings and impossible sightings spread from Vermont to the wilderness of Colombia, FBI Agent Alicia Raines uncovers a terrifying truth that defies reason and threatens everyone she loves. In a world where loyalty is fragile, legends are real, and moonlit forests conceal ruthless predators, the line between hunter and hunted begins to disappear. Some monsters are born. Others are made. And under the Wolfsbane Moon, no one escapes destiny.