Chaos
Chaos warbands uncounted make their home between the dunes or within the ruins of abandoned cities. Khorne, Tzeentch, Nurgle, and Slaanesh are all worshipped equally. Despite this, at the moment a mighty lord of Khorne known only as the Blood Maiden holds dominance, or at least so she thinks. These various tribes are constantly warring amongst themselves, waylaying careless travelers, or testing their luck against the walls of the vast necropolises. The kings occasionally lead armies forth to challenge a strong warlord or to eliminate a thorn in their sides.
The mortal followers of the dark gods are not alone as they seek aide from their demonic allies. Though it is hard for them to maintain their forms independently for long, it has been known for entire hordes of demons to wander the sands for years on end before they have been banished. The foul Skaven also make the land their home, generally preferring the dilapidated ruins of ancient cities long empty or the mountains of the Desert's Spine. Some claim that there may be a network of tunnels beneath the sands, but no proof has ever been found to back such a claim.
Destruction
There is an ancient saying amongst the Endless Deserts, "Show me a land free of the scourge of the Orruks and I shall walk hand in hand with the Usurper into the golden afterlife." While the meaning may be lost on some, the general idea holds true. The Orruks, ranging from fierce Ironjawz to lowly Moonclan Grots, have found a way to, if not flourish, at least persevere amongst the sands. Like a hard to root out weed the Orruks refuse to be dislodged despite decades of attempts by the kings. The Pharaonic Badlands are a favorite of the greenskins, although they have also been known to reside within the mountains, the coastal jungles, and even the vast dune seas themselves. There have even been reports of particularly piratical Orruks plying the Sour Sea.
To the west lies a massive sinkhole within the earth. No one knows how old it is or what caused it, but it has always been. Strangely, tribes of Ogors seem to congregate around it and have been known to attempt to abduct careless kings and priests to hurl into the holes bottomless depths. Whether this is for their own amusement or some darker purpose, no one is truly sure.
Order
The city of Bétone is the last bastion of the Free Peoples amongst the Endless Deserts. While its streets are home to all kinds of man and woman, the Equine Masters hold true dominion over it. These armies of man have been known to venture out into the sands to seek lost riches amongst the necropolises. At the heart of the city lies an ancient Realmgate which leads to a far off realm, presumably home to a much larger kingdom. The desert monarchs have never been able to fully breach the city's walls due to the seemingly numberless amount of reinforcements the horse lords can call upon. There have been several times though where the lords of Bétone have had to agree to a truce in order to avoid an endless war of attrition against the tireless dead. Amongst the forces of man there have also been spotted Duardin and Aelf, usually treasure seekers who are using the city as a base of operations or mercenaries hired by the forces of man.
Bétone is not the only place where the forces of order make their home. In the Desert's Spine mountains hardy clans of Duardin have staked their claim, although it is hard to say how many settlements they have or whether there are small encampments or vast fortresses since few of the desert kings bother to venture into the depths of the mountains. It is rumored that at least one Fyreslyer lodge makes its home within the boundaries of the deserts. These fiery warriors have been seen amongst the armies of the sands and a few have even been hired by the kings themselves.
Death
While the desert kings certainly rule supreme amongst the the dunes, they are not the only forces of death to call the land home. Nagash has been known to send envoys "requesting" aide and enterprising Soulblight Vampires have even tried to stake out a claim in the deserts, annoyed with the kings haughty nature. A vast Flesh-Eater Court makes its home amongst the ruins of Settrapolis, feeding off of the forces of Chaos and Destruction who try to live in the ruins. Unwary treasure seekers from Bétone and further afield are often their favorite prey. Who the Abhorrent Ghoul King is that makes those cursed ruins its home is a mystery to all.