The toxic surface world irregularly undergoes a phenomenon called Pulsation, where the land itself shivers and spasms, sometimes becoming twisted into itself and increasing in pressure until it bursts open, spraying boiling, poisonous red mist for miles. Sometimes when a Pulsation occurs, a grimace is said to appear on the Grimgate. The Pulsation phenomenon is shared with the upper caves of the underground.
Despite these facts, a precious few do manage to eke out livings here, either as wanderers on the surface, or as slaves to the monstrous entities who live in the twisting caverns beneath, mocking both life and death. Among the captured humans living underground, there is also a species native to this inhospitable environment: A dimunitive breed of insectoids known as the Xt'l-hysk (closest human pronounciation "kst͡ɬ ħʏsk", and actual pronounciation "12345621" where 1 is a hypopharyngeal click, 2 is a hypopharyngeal hiss, 3 is a vibrating mandibular click, 4 is a vibrating implosive pharyngeal hiss, 5 is a pharyngeal hiss, and 6 is a vibrating pharyngeal hiss).
The so-called 'surfacers' of Djaar tend to have skin and hair in darker hues, while those who exist underground as thralls to the varying terrors tend to have rather pale skin (their hair still comes in different shades, though usually nothing too colorful).
Despite it's unsual geography, the underground is divided into several vague territories:
The Upper Caves For unknown reasons, the upper caves are uninhabitable to any of the terrors living in the middle caves. The only living things that reside here are a limited selection of fungus, a few kinds of insects, and some bats. At any time, a countable number of humans can also be found wandering the upper caves, usually becoming lost and dying miserably. These humans are either desperate escapees from the underground, or vicious criminals forced to flee from the surface. The Upper Caves are extremely difficult to navigate, as they also occasionally shift and even meld into themselves whenever the surface world Pulsates.
The Middle Caves Though not all of it is controlled equally tightly, all of the Middle Caves fall under at least the stated control of one of these groups:
- Kingdom of Death Countless years of necromantic accumulation and exploitation have led to an inexorable presence of undeath within underground Djaar. Most of the time, the 'Kingdom of Death' is not a proper territory, and merely serves as a term indicating the general scope and scale of undead forces within Djaar. Due to the Kingdom of Death's existence, much of the caverns are virtually inaccessible due to the danger of even nearing their vicinity. Thus, the few passages that do exist between different powers in the Middle Caves are kept under tight control by the local forces. The exception to this standard is when a 'King of Death' emerges. This is a phenomenon that has, in the past, occurred naturally as many times as it has occurred artificially. A 'King of Death' is one with the ability to control and manipulate the vast majority or even all of the undead within Djaar. When such a being takes control, it inevitably marks a time of change for the political landscape, and oftentimes also a calamity for the powerful. Currently, there is no King of Death, the last one rose and fell over ten generations ago. Both humans and Xt'l-hysk are kept as playthings, subjects of unending torture.
- The Twelve Demonic Dominions Serving as probably one of the worst places to find yourself, not just in Djaar, but in Tashaya as a whole, the Demonic Dominions are each ruled by a powerful demon from Hell. Though their methods differ, each of the evil abyssal creatures share the same goal as per their fundamental nature: To cause as much suffering as possible. The omnimalevolence of demons is widely known across existence, though as inhabitants of a young world, the residents of Tashaya have little experience with their kind. Just like in their homeworld, the lands ruled by the Twelve Demonic Sovereigns are rifed with every conceivable atrocity, with every form of agony. No foul thought one could have has not been realized, and likely many times at that. To the most minute detail, every aspect of the structure of these domains has been specifically designed to extract as much pain and negativity as possible from the poor souls enslaved within.
- Oligarchy of Blood One of the four main groups of Vampiric Houses within Djaar. The Oligarchy of Blood is comprised of vampires of the Rubedas strain, also called the Original Strain, the Sanguine Strain and the Crimson Strain. Their most prominent houses are House Crimson and House Scarlet. Due to their vampiric nature, the Oligarchy only keeps humans as their livestock, and little or no interest in managing the native Xt'l-hysk. Known settlements:
- Viscerduom An outpost-sized Gate City belonging to the House Viscer.
- Oligarchy of Night One of the four main groups of Vampiric Houses within Djaar. The Oligarchy of Night is comprised of vampires of the Umbras strain, also called the Shadow Strain and the Dark Mystic Strain. Their most prominent house is House Nocturn. Due to their vampiric nature, the Oligarchy only keeps humans as their livestock, and little or no interest in managing the native Xt'l-hysk.
- Oligarchy of Sin One of the four main groups of Vampiric Houses within Djaar. The Oligarchy of Sin is comprised of vampires of the Daemonas strain, also called the Demonic Strain. Their most prominent houses are House Asme, House Vore and House Avarixum. Due to their vampiric nature, the Oligarchy only keeps humans as their livestock, and little or no interest in managing the native Xt'l-hysk. Known settlements:
- Luxerova A medium-sized city belonging to the House Luxe. Azr-Yl was raised in the manor here, though she was born in a smaller city.
- Oligarchy of Horror One of the four main groups of Vampiric Houses within Djaar. The Oligarchy of Horror is comprised of vampires of the Nosferas strain, also called the Monstrous Strain. Their most prominent houses are House Chimeres, House Barbares and House Famines. Due to their vampiric nature, the Oligarchy only keeps humans as their livestock, and little or no interest in managing the native Xt'l-hysk.
- The Fifth Strain Rumors tell of a fifth strain of vampires, whose bloodline have been corrupted by the presences from the Deep Caves
- Shadow Temple A mysterious organization of which little is known except their longevity and formidable hidden strength. Despite their all-but-certainly formidable hidden power, they have had little obvious effect on history, choosing to remain in the shadows and not exert their influence, never vieing for more power or control. Their goals are unknown, and few ever even encounter them.
The Deep Caves Unexplored and forbidden. Even the strongest, most wicked beings of Djaar's underground fear approaching this elevation, let alone pressing further into the incomprehensible madness.