Malbolge was originally an endless rocky slope where rockslides and avalanches of boulders were common. Numerous copper fortresses provided some refuge from the avalanches. Once ruled by Moloch, he was deposed during the Reckoning of Hell and replaced by The Hag Countess Malagard. Malagard has since died, her body expanding and imploding to the point that the entire layer is literally her remains, and Glasya, daughter of Asmodeus, currently rules Malboge. Now, the realm is alive, being formed from the flesh and bones of the Hag Countess.
As “The Crushing Lands”, Malbolge was a place of craggy, black stone and ash filled with stinking vapors, smoke, fire pits, and huge caves and caverns in which ancient Baatorians lurked. The air was hot and choking, and the whole layer existed at a steep tilt so that no flat terrain exists. Falling was a constant danger there, as were rockslides and avalanches.
The Sixth has had more known lords than any other layer of Hell. The earliest known ruler of Malbolge, the archdevil Beherit (along with his consort, Batna), was destroyed by Asmodeus for violating rules regarding the promotion of devils. Subsequently, the layer was ruled by Baalzebul through his viceroy, Moloch. When Moloch defied Asmodeus after the Reckoning of Hell, the former was exiled to Avernus, while rulership of the Sixth was passed on to Moloch’s leman, Malagard the Hag Countess. Malagard’s reign was short-lived, however, as she was deposed by Glasya, Asmodeus’s daughter and current Lord of the Sixth. As of Fiendish Codex II, Glasya used the Hag Countess’s body to reform Malbolge. Thus, the Sixth plane of Baator is in fact little more than the Hag Countess’s innards and bones. The Countess is technically dead, though her life essence still remains on Malbolge. The tunnel made from the remains of her throat still expands and contracts, as if something immense was breathing shallowly.
Malbolge is now a noisy place populated by tormented lemures, cornugons, and the occasional spinagon. Large numbers of lesser devils on this layer are missing all or part of at least one limb, or have some other sort of disfigurement or infirmity—a testament to the days when Baalzebul and Moloch ruled here, both of whom delighted in the torture of their subjects.
The nobles of this layer once dwelled in copper fortresses, whose metal plating helps ward off the worst of the falling stones. The Hag Countess once traveled between these fortresses in disguise, testing the gentility of her subjects; she despised mindless brutality, and destroyed those who committed it.
After the Hag Countess’ demise, those few nobles were not purged by Glaysa for treachery now live with the Princess of Hell in her palace, a grotesque, five-story building formed from Malagard’s skull.