Ok, I just got to say this:
First off, the power behind Darksun is taking familiar fantasy (elves, dwarves, dragons) and twisting it. The designers originally made it without those things before launching and said it felt to alien and sci fi like. You can read about it in the 30 years of D&D book that WOTC released a while ago.
Having cutthroat pirate elves who live in the desert, dwarves with no hair who become undead banshees if they die failing their life's work, wild and cannibal halflings, slave raised dwarf/ human breed muls, the dark magic created half-giants, ritual hunter thrikreen. Tribes of Gith in place of Orcs. Psionics being the dominate study of the mind over matter (like the force), wizards are hunted and killed, the world is highly savage, hostile and political. Armies of slaves and templars fight in the name of centuries old Sorcerer Tyrants who seek the last remaining resources on a world bleed dry. Athas is a husk of a world. With very little vegetation, water or metal to speak of. Life is violent and short here, heroes are few and far between. But there is hope, and the heroes who seek it leave their mark on Athas history.
The setting had no typical staples. No fey, no were creatures, no vampires, no good elves living in trees, no dwarves living in mountains, no dragons in the skies or being ridden by knights. Dark sun had no paladins or magic using bards. The bards it did have were court enetrainers trained in espionage and murder, and used as the agents of nobles and templars. Dark sun had no gods or much of a planar landscape to explore.
Dark sun was about a war and magic ruined world, where mortals are pressed under the yoke of power mad tyrants. A world where magic was used to rise humans to the pinnacle of power and then systematically wipe out the magic weilding races one by one. Athas is where the Cleansing War occured. When the twelve Champions of Rajaat carried out genocide against the non-human races, and wiped out the water and forests in the process. They killed each race, and didn't stop until they found out Rajaat was going to betray them and sparring the last remaining races alive. They performed dark rituals on one of their own (Borys) and turned him into the one and only "dragon" in the setting. They then defeated and imprisioned Rajaat and set the dragon to gurad the prison. The dragon went insane and now terroizes athas from time to time, demands tributes of wealth, slaves and food be given to it yearly and it leaves behind stories and legend on the lips of the few survivors in its wake. Most people do not believe in the dragon. No one realizes the truth in its creation or what it gaurds.
The thing about dark sun's sorcerers and their attempts to transform into dragons. As said earlier, it is a one way transformation. Only possible through mastery of dark magic and psionics. It involves rituals done over centuries, and it slowly transforms your human form and leaves you vulvnerable while doing it. Sorcerer Kings have to form entire priesthoods and armies around themselves, spend hundreds of years preparing for the rituals and then keep an eye on one another while their at it. Through the highest level of psionic, arcane and the power of their worshipers, they can alter their genetics with black magic and become "dragons". The cost is the last threads of humanity and their souls, the reward, the most powerful of black magic. If done wrong, they will go insane like the first dragon did.
This dragon is entirely not the typical shape shifting dragon of D&D or any other fantasy. If anything they are dragon in name only. If you look at the Brom picture you can see how they feel familiar but very different. That is the heart of the Dark Sun setting.
Now, you can see why Dark Sun tends to be voted as one of the most in demand settings to return. Why it is so different from typical D&D. Why it is all kinds of awesome
