From the introduction
The old world is in ruins, devastated by the ghost wars when literal Nightmares broke free to roam the earth. Humanity, now familiar with the existence of Blooded magic, tapped into the source and laid low many of the Nightmares and forced others into tenuous exile.
Humanity's defense against the Nightmares are OMEGA cells, cohesive military units bred with magic, and their specialized handlers. In the most dire circumstances, even witches and warlocks - humans who can reach through the boundaries of the paradigm and grasp the magic directly - are employed to hunt down rogue nightmares and their followers, minions, and terrible offspring.