Dark Sun

""I live in a world of fire and sand. The crimson sun scorches the life from anything that crawls or flies, and storms of sand scour the foliage from the barren ground. This is a land of blood and dust, where tribes of feral elves sweep out of the salt plains to plunder lonely caravans, mysterious singing winds call travelers to slow suffocation in the Sea of Silt, and selfish kings squander their subjects' lives building gaudy palaces and garish tombs. This bleak wasteland is Athas, and it is my home.""

Dark Sun is a Campaign Setting for the second and fourth editions of Dungeons and Dragons. Originally conceived as the default setting for a miniatures based wargame, the setting survived as a regular D&D world even after the minis game failed. There were two editions of Dark Sun, the second advancing the timeline a few years, inserting a bit of hope along with a whole lot of new troubles and detailing a larger portion of the world. After the end of Second Edition D&D, a group of fans kept Dark Sun alive using the Third Edition rules until the advent of an official Fourth Edition version in 2010.

The setting of Dark Sun is Athas, a once-beautiful fantasy world turned into a post-apocalyptic wasteland by centuries of corrupt magic and genocidal warfare. Most of the setting's land mass is made up of desert, metal is rare, requiring weapons to be made of less durable alternatives like bone and wood, there are no actual gods, and most of the standard fantasy races players might expect to find are extinct or vastly different from their normal forms. It was one of the first settings to incorporate the psionics rules to a large extent - to the point where all Player Characters and potentially any intelligent creature on Athas has at least a psionic wild talent. The Third Edition Expanded Psionics Handbook was largely built off of Dark Sun, though it made no open mention of the setting.

Dark Sun is also known for its Metaplot, some element of which is present in all editions of the setting. The bare bones is as follows: the Tyr region is dominated by 7 tyrannical city-states, the most powerful of which is, naturally, Tyr. Each city-state is ruled by an oppressive sorcerer-king (or, in some cases, sorcerer-queen); powerful spellcasters that are universally cruel and nigh immortal (the youngest sorcerer-king has over eight centuries under his belt). Tyr's sorcerer-king is Kalak, and on the verge of his ascension (think Mayor Wilkins-style ascension) the unthinkable happened: Kalak was slain at the hands of a slave revolt. Power immediately shifted hands to his former High Templar and killer, Tithian, who quickly outlawed slavery and declared Tyr to be a Free City. There are even talks of setting up a senate, giving people rights, and establishing a rudimentary justice system. However, all is not well in Tyr. Multiple factions with opposing interests are vying for both power and a place in the new government, and almost all of them need to be in agreement in order for anything to get done. On any given day, the Free City of Tyr is teetering between anarchy and full-blown civil war. If that weren't enough, the vultures have begun to circle; with Kalak gone, the numerous bandits and raiders of Athas have declared open season on Tyr's trade roads. Worse, word of Kalak's death has begun to reach the ears of his rival sorcerer-kings, who, aside from consolidating their own power bases to ensure that they avoid Kalak's fate, have begun their machinations against a Tyr they view as hopelessly exposed. The first truly good thing in written Athasian history has happened in Tyr, but it is a meager candle in the face of the tidal wave of darkness hoping to extinguish it.

Dark Sun games -- as one might guess -- are notoriously deadly. In 2nd Edition, characters started at level three just so they would have a fighting chance, and the boxed set introduced the "character tree": players were advised to keep three backup characters around in case their current one died.

The MUD Armageddon is loosely based off of the Dark Sun setting.

Contains examples of:
The world was dying quickly, and it got to the point where entire continents that hadn't even been touched by the disciples were dying. This made them take pause, so they turned on Rajaat and imprisoned him in the nothingness outside the world. Having done that, the disciples grabbed their own plots of land in the Tyr region (the only habitable region), the strongest of them turned into the Dragon of Tyr, and things were like that for a few hundred years until a revolution in Tyr started, which is where the setting picks up.
 * A God Am I - The sorcerer-kings. They're not technically deities in game terms, but they still enforce worship of themselves and channel divine magic to their templars.
 * After the End - In more than one adventure, it is made painfully clear that Athas used to be a nice place.
 * Ascend to A Higher Plane of Existence - Any sufficiently powerful wizard/psionicist can try this in 2e, though it is a long, painful, multistage process in which a single mistake will kill you dead. Evil characters turn into dragons while good ones turn into angelic energy beings. All of the big bads are in the process of becoming dragons. Did we mention that becoming a dragon is a process that requires life energy as a catalyst, meaning that every single dragon is the product of an act of genocide? This is why there are no orcs on Athas.
 * Thematically remains, though simplified, in the 4e version. The Avangion, Dragon King and Pyreen are epic destinies for Arcane characters, Arcane characters who can use Arcane Defiling, and Primal characters respectively.
 * Ban On Magic - Openly practicing arcane magic, defiling or not, in a city-state without a license is a serious offense.
 * Beach Episode - Subverted. Your characters might think they're in for a break if they find the idyllic Last Sea, but they'll soon learn otherwise.
 * Big Creepy Crawlies - Thri-Kreen are a playable race. Fairly decent though.
 * Black and Gray Morality - an intentional part of the setting is the concept of "what will you do if the circumstances are bleak enough?" The inherent concept of Dark Sun is that the villains are terrible, but the heroes themselves are often forced to commit terrible acts to complete their goal, or simply to survive. One of the first adventures for the setting opens with the party being part of a band of slaves whose slavers have been slain, but there isn't enough water to sustain everyone. The party is thusly given a choice: do they kill the other slaves to spare them the agonies of death by thirst, abandon them to the wild and steal all the water themselves, or insist on sharing the water and risk none of them surviving? Depending on a particular campaign, though, this could be darkened to Black and Black Morality, or lightened to Grey and Gray Morality.
 * Brainina Jar - The Mindlords, who rule and preserve the Last Sea.
 * Canon Dis Continuity - The 4E revamp follows more-or-less the original story, but sounds a lot less weird. The Primordials either kill or drive off the gods, so there's no more divine magic for the world. A powerful psion named Rajaat discovers arcane magic, now able to be found due to a flaw in the world that the lack of divine magic caused. Arcane magic, being flawed, defiles the world with each use, so Rajaat decides to teach people how to use it. Then, he and his closest disciples start a genocide on races that he considered impure.
 * Combat By Champion - A very common way of settling disputes, whether it be nobles betting on gladiators or nomadic warriors fighting for their tribe's right to a watering hole.
 * Continuity Reboot - The 4e version ignores much of what is mentioned in the Fanon Discontinuity entry and starts all over again with essentially an "updated" version of the very first box set continuity.
 * Crapsack World: The world is dying, the people responsible are in control of everything, what's left of civilisation may collapse utterly if they are removed, most people can't even believe in heroism any more because sheer survival tends to require brutality and selfishness, and those who achieve power tend to to do so only because they are at best ruthless and more likely utter bastards. That more or less sums up the situation of Athas in a nutshell.
 * Crossover: Very infrequent; back in 2nd Edition, when every other setting was crossing over left and right, it was made clear that Athas was a backwater with very limited knowledge of planar travel and no knowledge of spelljamming. It did cross over with Ravenloft, though--the city-state of Kalidnay was drawn into the Dark Domains when its ruler attempted to become a dragon and his high templar murdered her family in his name. A bunch of the notorious Cannibal Halflings also make a quick cameo in Baldur's Gate 2, of all places. There was also an attempted Githyanki invasion, but after discovering what Athas was like, they sealed the portal to it.
 * Cultural Translation - In Universe. Urik government got a clue about Kreen pack mentality long ago and established a simple policy: gate guards explain to every entering thri-kreen that the city is a large pack and the newcomer is welcome to join any of its many clutches, but must obey laws of the pack. Humanoids in the city has little to no problems with local thri-kreen as a result.
 * The Dark Arts - Defiling is more or less abhorred by everyone, up to and including other defilers.
 * Darker and Edgier - See above. Then compare to most other D&D settings at the time.
 * Death World - Athas is so unsuitable for life -- and yet simultaneously so full of ridiculously deadly forms of it -- that your party is almost as likely to be wiped out on the way to the dungeon as to die in the dungeon itself.
 * Elemental Powers - In the absence of true gods clerics receive their powers from the elemental planes. This does not excuse them from the normal clerical conducts-they are entirely capable of losing their clerical powers in a manner quite similar to how a normal cleric can have them taken away by their god.
 * End of an Age - Very much so. Tombs and temples from the Green Age dot the Tyr region, all of them either empty or filled with stuff that is very good at killing you. Of particular mention is that since metal is so rare, the techniques for doing stuff with it (i.e. blacksmithing of any sort) have been lost for generations. This means that even a mundane iron sword is a priceless relic of a far more technologically advanced time.
 * Enemy to All Living Things - All arcane casters, to some degree. Arcane magic (rightly referred to as "defiling") inherently saps the life out of the surrounding terrain, killing plant life, sterilizing soil, and (in some cases) actively siphoning vitality from living creatures. There is a method of safe spellcasting known as "preserving", but defiling is both easier and inherently more powerful, so more people do it. Thus, wizards, sorcerers, and other arcane casters (even the preservers) are viewed by the common folk as walking embodiments of death and hubris.
 * Everything Trying to Kill You - The only setting that gives you the CR for a cactus.
 * Everythings Better With Dinosaurs - Pterrans, Humanoid Pterodactyl, are a player race.
 * Fan Service - The artwork in spades. Word of God has it that the designers threw out the alternative of a frozen dying world specifically because the concept-art didn't have enough skin.
 * Fantasy Counterpart Culture - Many of the city-states fall under this trope. This includes Balic (ancient Rome, complete with Patricians and Praetors), Draj (very obviously the Aztecs), Raam (either Egypt or India—there's evidence for both), Gulg (Darkest Africa), Tyr (the Phoenician city of Tyre, presumably), Urik (Sumer), and Nibenay (probably a mix of China and Tibet). The halflings of the Forest Ridge seem vaguely Amazonian.
 * Flight Strength Heart - There was a special kit to make characters with a non-coherent set of abilities by combining normal powers and random wild talents ("Tribal Psionicist" in The Will and the Way)
 * Gaias Lament - Athas. Used to be a nice place.
 * Gaias Vengeance - In the 4e versions, the Primal classes (more so than usual), and to an extent the Primal-based Elemental Priest and Primal Guardian themes. Quite literally the "Voice of the Ravaged" paragon path, which is a character who deliberately seeks out the most scarred and psychotic primal spirits to act as a conduit for their rage and hate.
 * Gladiator Games - Almost every community has an arena or fighting pit, and Gladiator is one of the setting-specific player classes in the pre-4th editions. In 4e, it's a character theme, and also a new build for the Fighter.
 * Half Human Hybrid - The half-giants, a magically engineered race. Muls are also more or less setting-specific; they're half-dwarves. They don't occur naturally but slavers will force-breed them because muls are considered some of the best gladiators in the world. There's also half-elves, but they're not terribly different from those on other worlds.
 * Horse of a Different Color - In a world with no horses, people ride anything from camels to large dragonflies to even larger beetles.
 * Humans Are Bastards - The humans, led by a pyreen, conducted a genocidal campaign against the other races, driving many (including orcs, goblins, and gnomes) to extinction. His human lieutenants turned against him and gave him A Fate Worse Than Death after, though, but more becuase he intended to wipe out the humans after the war and give the place back to the halflings than because they weren't bastards.
 * Loads and Loads of Races - In addition to the usual humans, elves, half elves, halflings, and dwarves, players could play half-giants, thri-kreen (Multi Armed and Dangerous mantis people), pterrans (flightless pteranodon people), aarakokra (bird people), and muls (half-dwarves). The 3.5 Dragon update added Maenads (sparkly screaming people).
 * Official 4e races: Humans, Elves, Eladrin (the rulers of "The Land Within the Wind", the almost destroyed Feywild), Goliaths (reflavored as Half-Giants), Dwarves, Half-Elves, Mul, Dragonborn (reflavored as Dray), Halflings, Thri-Kreen, Tieflings (humans with demonic ancestry), Genasi (elementally-imbued humans), Kalashtar (psionically adept humans first introduced in Eberron), and Minotaurs ("Half-Beast Giants"). Suggestions for including other races, at DM's discretion, includes time travellers, planewalkers, and mutations spawned from the Pristine Tower and Sunwarped Flats.
 * Luck Manipulation Mechanic: 4th edition suggests an optional rule that allows a player the choice to re-roll the D20 attack roll whenever they originally roll a "1" (indicating a "critical miss"). The new die roll must be accepted, however the character's weapon breaks.
 * Enhanced weapons break if the result is a 5 or less.
 * Magic Is Evil - Played with. Arcane magic is inherently evil, but there are ways of casting it that don't involve killing plants and sapping the life from the soil. However, the "healthy" way of casting magic is inherently more difficult, which means that people looking for a quick route to power generally choose the evil way. Thus, even if your wizard has never hurt a fly, people will still be trying to kill him for being an evil spellcaster.
 * Master Poisoner - Dark Sun bards are known for such a practice and learn to prepare and use more poisons with the level advancement.
 * Multi Armed and Dangerous - Thri-Kreen have four arms, as do the giant-like brohgs.
 * Nintendo Hard - Valley of Dust and Fire, the module detailing the city of Ur Draxa, home of the Dragon of Tyr. It is by far the single most impossible and impenetrable fortress ever statted in the history of AD&D. Yes, that includes the module where you have to go to Orcus' layer of the Abyss and steal his wand, and the friggin' Tomb of Horrors. It's so hilariously and yet convincingly overdone that it Crosses the Line Twice into being its own crazy kind of awesome. Best Mordor rendition ever.
 * It is entirely possible for a high-level adventuring party to die without ever having made it within thirty miles of the place, just from the weather. Not to mention the surrounding sea of lava. Which can only be crossed by a series of jumpgates directly linked to the Dragon's mind. Then you reach the outer walls. Which are 720 feet high and a quarter mile thick. And have no gates, but instead require you to win a psionic power contest with a ginormously powerful psionic construct before the passwall portal will temporarily dematerialize for you. Did we mention that the gate sends out a mental alarm whenever unauthorized psionic contact is initiated? Assuming you've gone through all this, congratulations, you're now past the introduction and actually get to try and survive in the city. Good luck!
 * And no, it doesn't let up once you get past the outer defenses. *shudder*
 * Our Dragon Is Different - There is only one dragon in the entire world, it's an unbelievably powerful defiler and psionicist, lacks wings, and is the closest thing to a Physical God wandering Athas. It's bad news.
 * Our Elves Are Different - They are quick, sneaky desert raiders who no one else fully trusts. For very good reasons. Oh, and they're seven feet tall.
 * Halflings and Dwarves are different as well, the former being mostly savage cannibals who inhabit the few remaining jungles and the latter hairless brutes who are generally found being used as slaves due to their amazing endurance.
 * Our orcs, meanwhile, are extinct. And so are our gnomes. And goblins. And ogres. And trolls.
 * Our Fairies Are Different - In 4e, the inherent haughtiness and xenophobia of Eladrin has been ramped up to the point that the majority of Athasians don't even believe they exist. With rampant defiling rapidly shrinking the Land Within the Winds (read: the Feywild), most Eladrin that people encounter are wandering assassins charged with slaughtering any and all arcane spellcasters they meet in hopes of saving their homeland.
 * Precursors - The rhulisti (ancient halflings) from 2nd Edition.
 * Psychic Powers - Presented as the evolutionary alternative to magic, referred to by the locals as The Way. Some people have them through training, some people spontaneously manifest them, but almost everyone has them to some degree, including most of the nonsentient monsters. With the exception of Planescape, home of the cranium rat, this is the only campaign setting where you risk having your head exploded by vermin.
 * Sand Is Water - The Sea of Silt, which is more or less exactly what you'd suspect.
 * Scaled Up - The goal of pretty much every sorcerer-king
 * Serious Business - using Arcane magic
 * For those who understand and accept the preserving way of casting Arcane magic - using defiling Arcane magic.
 * The Spartan Way - Athas is so harsh that just living here qualifies. Hilariously, an extraplanar invasion by the githyanki ended with the githyanki running away from the desert full of psionic survivalist badasses and marking the entire plane down as a 'Do not EVER try invading here again. As a matter of fact, just seal the whole damn portal!'
 * For reference, in earlier editions, the rules stated that the average human in Athas was a third-level fighter, equivalent to a decently experienced adventurer in most other settings; in most settings back then, average humans wouldn't have any levels at all.
 * Stepford Smiler - Everyone who lives around the Last Sea, where happiness is enforced by law. You had better have happy throughts, or the psychic police WILL MAKE YOU HAVE HAPPY THOUGHTS.
 * Time Skip - The 3E revamp in Dragon.
 * Walking Wasteland - One of the two types of playable wizard in the game, Defilers, drain the energy of all plant life in a radius equal to the level of the spell they're casting in feet or yards. If that weren't enough, defiling also sterilizes the soil, ensuring that nothing will grow in that spot again.
 * We Are As Mayflies - Not just humans. Every race is shorter lived here than in other settings (and less likely to die of age anyway) but the champions are the thri-kreen, who reach maturity at six years old and never live past thirty-five. The exceptions are the half-dozen Sorcerer kings (and a few others) who have been around for millennia.
 * World Half Empty - The Halflings want to eat you. Less so by the Revised Edition.
 * World of Badass - The average person in the setting is a 3rd level Fighter.