Malbolge

Malbolge was the sixth layer of the Nine Hells. It served as the prison of the Nine Hells.

Geography
There was significant disagreement between cosmologies on the nature of the sixth circle of Hell.

As a Great Wheel layer, Malbolge was a gargantuan tumble of angular black stone blocks, each block ranging in size from a small city to a large metropolis, that formed a pile hundreds of miles/kilometers thick. The randomly tilted and ill-fitting blocks were honeycombed with angular passages and caverns causing non-flying travellers to frequently need mountaineering skills and risk avalanches. Stinking clouds of vapor rose up from the depths and lit the sky with the color of blood, causing cosmologists to speculate that the blocks of Malbolge may have rested on an infinite sea of lava. Corroborating reports have been heard of flammable materials left on the ground spontaneously combusting. Most habitations in Malbolge were copper-clad fortresses built from black stone.
 * Great Wheel:

The landscape of the layer was similar to the plane of Gehenna: a steep, infinite craggy incline often subject to avalanches that crushed most anything that got in the way. The copper-shod redoubts were teardrop-shaped or otherwise engineered to deflect tumbling boulders, but even those could not long withstand a direct hit from a major avalanche.

In the World Axis cosmology view, Malbolge was another huge cavern connected to Stygia by icy canals that ran hundreds of miles/kilometers before reaching their destination. A former godly inhabitant had shaped the realm into a vast garden with fountains, towers, reflecting pools, and all manner of landscaping delights. With the coming of the devils, Malbolge was still beautiful on the surface but creeping corruption permeated the realm, twisting the beauty, perverting the architecture, and poisoning the pools.
 * World Axis:

Government
Malbolge was ruled by Glasya, Asmodeus' daughter. Her court was primarily comprised of erinyes, paeliryons and succubi. She has only one Duke, Tartach.

History
Malbolge was once ruled by Moloch. One of his chief advisors, Malagard, counselled him to rebel against Asmodeus during the Reckoning of Hell, and when Moloch was overthrown, Asmodeus installed her in his place.

However, Asmodeus had only promoted the Hag Countess so that the other Lords of the Nine would not notice his designs. He caused the Hag Countess' body to grow to gargantuan size and rupture, turning the formerly mountainous Malbolge into a realm of decaying flesh. She was replaced by Glasya.

Notable Locations

 * Hair Forest: A closely packed forest of massive, scaled hairs.
 * Lake of Bile: Despite its name, it was a group if vile, toxic lakes.
 * Maggoth Thyg: A mysterious cavern located at the bottom of one of the many rocky slopes of Malbolge. Devils are terrified of entering this cavern and all who have entered have never returned.
 * Ossiea: Glasya's fortress, built near Hair Forest from the remains of Malagarde's enlarged skull.

Inhabitants
The layer's most numerous inhabitants were erinyes and paeliryons, who were favored by Glasya. Other devils found in this layer were barbed devils, bone devils , cambions , ice devils , legion devils , lemures , nupperibos , spinagons , storm devils , and war devils.

Non-devils dwelt there, including giant centipedes, giant spiders , giant wasps , hell louse , kalabon and night hags.