Until recently, the subtle, fiery Mephistopheles operated cults for Asmodeus as part of his vassalage to the greatest of the archdukes. Now Mephistopheles is slowly relinquishing these subcontracted duties to build a peculiar cult of his own that promises its members control of hellfire - a relatively new magical substance of his design. This sect has hidden cult aspects because it’s as much a soul-harvesting operation as a means of entrenching diabolical power in the Material Plane.
Temples to Mephistopheles feature massive fire pits in which sacrificial victims are burned alive. Favored initiates are granted access to hellfire spells in exchange for the performance of corrupt or obeisant acts.
Cult leaders, called hellfire masters or hellfire stewards, favor the ranseur as a weapon.