The City of Dis
The second layer, Dis, is both a layer and a burning city of iron known as the Iron City of Dis. The walls of the buildings of the city radiate extreme heat, as do the stones of the streets; more than brief skin contact results in severe burns. The Archduke Dispater rules this layer from the Iron Tower, an impregnable fortress that reaches far into the sky and can be seen everywhere on Dis (literally; by looking to any direction in the skyline one can see the Iron Tower).
A notable feature of Dis is God Street, a place filled with buildings that are actually the godly realms of various lawful evil deities that have not earned enough worshippers to earn a realm on another layer of Hell or another plane entirely. It is suggested that homebrewed (DM created) lawful evil deities get a realm on God Street.
Although the Iron City of Dis has a wall, the transition from plain to the city itself is imperceptible. One moment a traveler is passing an iron spur, the next the traveler is in the middle of the city with the mighty iron walls surrounding everything that can be seen. It is thus much easier to enter the Iron City than it is to leave it; to leave, one must pass through the heavily guarded city gates (unless the traveler has means of crossing planes of existence).
The iron walls and streets of the city smoke with intense heat, burning those who touch them without protection. Abishai, erinyes, spinagons, and lemures are common – so are soul shells, petitioners who retain their humanoid forms and memories, the better for Archduke Dispater to torment them. Bezekira, kocrachons, rakshasas, and hamatulas are also found thronging the streets of Dis.
The most prominent building in the Iron City is Dispater’s tower of iron and lead, a skyscraping edifice that constantly changes shape. The streets, too, are constantly shifting, constantly being rebuilt by the tormented petitioners, confusing and sometimes choked with garbage.
Despite all this, Dis is the most populous and wealthy city in Hell, filled with planewalkers of all types who come to sample the city’s terrifying delights.
The realm of Druaga, the Refuge of the Fallen, exists on the plains far outside the city walls. Dis is largely flat, with a sky of smoky green occasionally lit up by lightning. Black, stagnant rivers criss-cross its plains. Monolithic spurs of blackened, unworked iron – natural formations, as much as anything in Hell is natural – thrust out of the plains, growing more frequent as a traveler approaches the Iron City itself.