The story is set in a fictional Germany and centers around the outbreak of biomechanical creatures named "Demoniacs", who rise from corpses and attack people mindlessly. The Demoniacs have the ability to merge with most technology including cars and motorcycles, not only gaining control of them but also enhancing their performance greatly. Against them is a group of people known as XAT, Xenogenesis Assault Team, who police these Demoniacs in an attempt to keep the peace and discover the reasons for the "Demoniac" change. All the while, a number of human-turned-Demoniacs appear. Some use their powers for good whilst others for evil. One will rise above all other Demoniacs to become the "Blassreiter".