City of Dis

The Iron City of Dis, better known as the  City of Dis or simply Dis, is a large settlement on the second layer of the Nine Hells.

Description
The City of Dis is incredibly massive. The walls, buildings, and other structures clutter the immense black metropolis and glow at the edges like heated glass. The city is a broken maze of metal ramparts built into miles of steep hillsides and shattered towers framing an endless labyrinth of twisting alleyways.

The air is extremely hot and distorts with the heat as smoke rises from the streets themselves, with the occasional ash or ember drifting through the air.

Most of the buildings are built out of dark stone, climbing for many stories. The architecture is hooked to the corner as the monolithic deep reds, blacks, and grays, nothing belies an exterior that would seem to be welcoming to a traveling pack of people. At the center, visible everywhere in the city, is the Iron Tower, an impossibly colossal tower of black iron and lead that stretches for hundreds of miles into the sky before vanishing into the dark, clouded expanse. The Iron Tower is the throne of the archdevil Dispater and stands ever-vigilant over his Iron City of Dis.

Demographics
Like the rest of the Nine Hells, the city of Dis has a very structured hierarchy. There are different kinds of devils, and each devil has to answer to different devils who have fealty over them, up to greater devils and then archdevils, who in turn all owe their fealty to Asmodeus. Devils are at constant war with the devils who are in fealty to other devils.

Not all the devils are in the same system. There is a promotion-demotion system in which devils advance and are demoted, but there are other fiends existing in that space that aren't part of that system. Rakshasas, succubi, and incubi are somewhat outside of the system. There are other fiendish creatures that traverse between both the Abyss and the Hells based on what their interests are.

Tieflings are quite often found there, because of the social construct, in this city specifically, that revolves around the cross-section between the mortal races and devils. (Similarly, Vox Machina encounters a half-devil cambion in the city.)

It is not uncommon for mortals to wander through the City of Dis, specifically because it is where goods, gold, and largely souls are traded to and from various structures or entities within the Hells and beyond. To just consume or eat someone means nothing. The true worth of a soul is in corrupting it. And they do so through enticing, through corrupting their morals, through driving mortals through bargains and pacts to end up twisting into entities of order and evil as well, and then claim their souls. Contracts are a big thing in the City of Dis.

The "insects" that dwell in the city are technically extremely small fiends.