All layers of the Abyss were hostile to life and Ahriman-abad was no exception. Having a climate that was inhospitable to most mortals and demons alike, the 752nd Layer of the Abyss was a relatively unimportant and rarely visited layer.

Features

Ahriman-abad was a large, mostly uninhabited, desert waste. Characterized by its large, stationary red sun, which remained fixed at its apex, and the black sands which covered nearly the entirety of the plane, Ahriman-abad did not have much to recommend it. However, if one could bear the oppressive heat and nearly certain death, the layer did have several unique qualities which made it of interest to various demons, planar scholars and adventurers.

One of the most notable of these features was the apparent origin of the black sand which covered the plane. Although it looked and behaved in most respects like normal sand, this substance was actually the collective remains of the creatures who perished on this layer. Creatures who died on Ahriman-abad simply dissolved into a fine black particulate – the black sand. As discovered through further experimentation, this transmutation occurred regardless of the means of death or the nature of the creature which was killed and resulted in an amount of sand proportionate to the mass of the deceased creature.

A possibly related, but certainly more consequential quality of the plane was that, accompanying the destruction of creatures’ bodies upon death, their souls were also destroyed or imprisoned. This phenomenon was known as "The Death Curse of Ahriman-abad". If a creature died on the layer, their soul was either destroyed - if it was weak - or contained within the plane. Dead souls were thus completely inhibited from leaving the layer: they could not be resurrected, continue on to their actual location of afterlife, be reconstituted in their home plane, or diffuse.

Landmarks

The Iron Tower was the residence of the Demon Lord Ahrimanes. Located deep within the black sands of Ahriman-abad, externally it appeared to be a massive, smooth and elegantly curved spire of iron. There was no visible door. When approaching, one could feel the heat radiating off the metal, which would severely burn anyone who dared touch it, even creatures with supernatural resistance to heat. It was far hotter inside, but there were no reports of anyone except Ahrimanes entering it.

Most believed that Ahrimanes used the tower as a tomb for his still body, while he used the tall spire as a kind of antenna to astrally project himself upwards and out of the Abyss into the wider world.

The Glass Expanse was a large swathe of black sand which was turned to glass. Tinted the same shade of black as the sand, but still somewhat translucent and smooth to the touch, this region was completely flat and featureless. Some visitors believed to make out the shapes of buildings and creatures frozen deep down in the glass, but the few attempts at excavating these sites were thwarted because the glass was at least as hard as adamantine.

There were some periodical teleportation portals which ended in small rooms entombed in a smooth darkness. These were believed to be located in the Expanse. However, most of these portals quickly collapsed, and travelers couldn't stay much longer than a few minutes.

Blood Rocks was a large outcropping of black rubble, cliffs, and ravines in the middle of the sand wasteland. A number of relatively permanent teleportation rings landed on flat plateaus in the blood rocks. Various small hills, most notably the Lord's Altar, were commonly used as execution or duel platforms. Most execution and champion parties who travelled all the way down to Ahriman-abad went for the Blood Rocks, because they were relatively safe, easy to reach, and had all the necessary infrastructure.

Still Pond was the single source of water on the layer. It was nothing more than a tiny brackish pool underneath a rocky overhang. However, it was ringed by stones featuring untranslatable markings, and there were odd patterns on the stone overhang itself. The origins of the pool were shrouded in mystery, and neither Ahrimanes or the Cacodaemons had anything to do with it. The water itself is brackish, very warm, and unpleasant to drink. Surprisingly, it did not boil and evaporate.

The Glass Tunnels were made completely of a black glass, apparently the same as that of the Glass Expanse, which opened up in seemingly random locations across the dunes and led to nowhere. They seemed to repel the black sand – none of the tunnels were filled in and hardly any grains got in. Again, their origin was shrouded in mystery, and most likely predated Ahrimanes. Some theorized that Ahrimanes himself was scouring the desert, digging for something unknown.

Dangers

The plane’s large, red sun dominated the sky and remained stationary at the apex of its arc. As a consequence, the heat was oppressive and dangerous. Compounding this issue was the black sand, which absorbed much of the sun’s rays, becoming superheated to the point that touching it resulted in burns. This was very problematic since winds or disturbances (such as walking) could result in sand flying into the air and coming in contact with individuals’ skin. This resulted in relatively small, but serious burns which accumulated over time. The sand also proved problematic for beasts of burden, even those native to desert climates, being too hot for them walk comfortably on. Non-demonic visitors often necessitated magical heat protection or had to wear clothing which thoroughly covered their body and sturdy, high cut footwear to prevent the pooling of sand in their shoes.

There was no water except in the Still Pond, and local flora and fauna were essentially non-existent. Shelter was also hard to come by; although there was an occasional rocky shelf or outcropping, there were very few places to get a break from the unrelenting, never setting sun. Sleeping on the ground without substantial insulation was impossible due to the heat of the sand. It was rare for humanoid visitors to remain on the plane for so long that they actually needed protracted rest, however.

Inhabitants

Even demons had a hard time establishing roots on Ahriman-abad and, as such, there were very few creatures which called this layer home.

Lord Ahrimanes

The most notable of the plane's residents was the Demon Lord Ahrimanes. Not much was known about him, as he was one of the older demon lords and went to great lengths to isolate himself from even other denizens of the Abyss. Notably, he on repeated occasions allowed his layer to be shifted downwards.

Ahrimanes became the sovereign of the 752nd Layer sometime before the Celestial Wars. While other demon lords fought over more desirable layers, Ahrimanes claimed his with little to no conflict due to the plane’s few interesting features for the living. Ahrimanes resided there ever since, isolating himself from the affairs of both the Abyss and the planes beyond. At some point, Ahrimanes constructed a massive iron tower deep inside the deserts of his plane and sealed himself inside.

Ahrimanes' neutral stance was beneficial to his neighbors, because they were essentially allowed to enter and leave Ahriman-abad as often as they pleased. Because few resided in this inhospitable place longer than a fight, Ahrimanes didn't care much for them, and they could use the plane as their cemetery.

Cacodaemons

The only other creatures that were known to live in Ahriman-abad were the Cacodaemons. They travelled, serpent like, beneath the sands. They were scaled, worm-like creatures, bearing a single eye centered on their face, and had huge maws. Most were black and some were red. They were up to a dozen meters long. Beyond their basic appearance, knowledge of them was extremely limited as they were very rare to observe when wandering the layer; there were even some theories that only one, color-changing entity existed. It was unknown what, if anything, Cacodaemons ate. Some believed the creatures were responsible for the unique soul-trapping features of the layer.

Culture

The sands of Ahriman-abad were one of the only ways in the chaotic Abyss for the remains of a demon to last more than a few hours. Thus, it became a tradition for more powerful demons to travel to the low plane when they knew their death was apparent. The soul-capturing features of the plane were very important, because it both made sure a demon lord's soul wasn't taken and put into slavery by someone else, and that the lord never came back, in the case of executions. Because souls never diffused, some lords felt like they could continue on "living" eternally here. Often, one of the only conditions of surrender of a demon lord was that it be executed on Ahriman-abad, and refusing such a wish was seen as a major crime. Additionally, many fights of champions - when two lords didn't want to outright go to war, but also needed to find a resolution to some major dispute - occurred on the layer, because the champions invested into such a fight were often very powerful entities who did not want their corpses to be lost and forgotten on some other plane.

This made the layer into a true cemetery of the great, one seen as a neutral ground by demon lords and which should always be open for visits.

In the frequent battles between demons and devils, it occasionally happened that prominent devils were captured. In this case, they were brought on the long journey down to Ahriman-abad for execution. Devil souls couldn't return to the hells and be reconstituted there, and the imprisoned souls could always be used as a source of knowledge.