Takes place in a world overrun by demons. Although Dr. Faust anticipated the arrival of this terrible threat for a long time, he is now at the brink of death and can no longer fight it on his own. In order to fight against evil, he entrusts Shingo Yamada with the mission of saving the earth by eliminating creatures. On the young boy's forehead, a birthmark seems to designate him as a demon hunter! To aid him in his important task, he summons a demonic creature by the name of Mephisto, with whom he decides to make a blood pact before embarking on the ultimate battle to save mankind.