One of the few top class arch demon of Makai, on the same level as Satan himself. He is the main villain of this manga, and Mikami's arch nemesis. Ashtaroth's plan was to control the world using the "Cosmo Processor", which lets him gain control over the boundaries of life and death, freely arranging the molecular structure of everything. When Mikami and company destroyed the device, the raging Ashtaroth tried to destroy the human world, but in the end he lost against Yokoshima's true power. It is later revealed that Ashtaroth was only trying to defy his fate as a 'villain' and was seeking for death, but was unable to because of the balance problem.