When Earth's colonies go silent, Legion Varus drops onto Kepler-62 expecting a routine investigation. Instead, they find something far worse than death. The colonists aren't dead—they're changed. A new kind of enemy has arrived in Province 921, microscopic invaders that transform humans into perfectly coordinated killing machines. These "Demon" parasites don't just control minds, they improve them, creating an army that works with terrifying efficiency. As cities fall and soldiers turn against their own, Centurion James McGill discovers he's mysteriously immune to infection. But immunity comes with a price. To save humanity from becoming pawns of a new Galactic species, McGill must navigate a web of seduction, betrayal, and impossible choices. Some invasions come with warships. Others come with a whisper, a touch, and a promise of something better. The question what happens when the enemy might be right? DEMON WORLD is the latest action-packed entry in B.V. Larson's bestselling Undying Mercenaries series.