In their foolish quest for power, the Nemedians experiment with forces beyond their control. They attempt to recreate the black plague that swept their country, and unleash it upon their foes the Aquilonians.

The latest threat to the peace of Aquilonia comes from no natural source. It is not the thunder of a Nemedian army's march, or the howling cries of a Pict tribe running to battle. Instead, the Wild Lands and the frontier villages scattered throughout its reaches are bedeviled by the presence of creatures earning the name ‘Dark Beasts' from the lips of terrified peasants.

These behemoths tread through the cold pools of bog water like manifestations of the defiled swamp, all muscle and slime and hatred.