The Arch Devil Alastor, the Executioner of Hell, is the mightiest of the pit fiends, standing 16 feet tall. This horror has a body cloaked entirely in hellish yellow flames, and huge bat-like wings spread from his scaly body, which glows faintly like cooling steel. Long, ape-like arms end in clawed hands that wield the wickedly curved infernal iron battleaxe Grimfang. The beast's coal-black eyes are lit with glinting red pupils, and his mouth is filled with row upon row of shark-like fangs.

Alastor's Keep is found on the great battle planes of Gehenna where the princes of darkness contest against one another for dominion over the throne of Hell. Alastor is an impartial observer in these contests between the demon lords. He seeks only to quench Grimfang's insatiable thirst in the blood of his brethren and any demons or angels Alastor can get his mighty paws on. Alastor takes great pride in his job, and his axe never falters. When tasked with the execution of a traitor or prisoner, Alastor does the job, neat and clean every time.