From the back of the core book:
An apocalyptic dark fantasy tabletop roleplaying game set within a feudal, medieval era. You are a survivor, an adventurer fighting for your soul within a world filled with darkness and monsters. Delve into the ancient ruins of races long dead and otherworldly beings lost to the teeth of time. The black towers of the Void Gods hold untold treasures and mystic artifacts that wield esoteric technology, or what we call “magic”.
The world Koth has suffered through the Apocalyptic Prophecies with the final tragedy yet to be fulfilled. The legends say that the world was once infested by demons and for eons they have been imprisoned. Now stories are spreading around the campfires of the dead rising from their graves and the very darkness of the Veil Myst coming to drag souls to the Black Plane. If this is true, the Demon Gate has opened, and it will take more than just heroes to stop it.