One of the many ways that Dark Sun differs from your traditional Dungeons & Dragons setting is that there are not native Dragons. Oh, there are Athasian Drakes, but those are basically giant feral reptiles with innate elemental psychic powers - the Fire Drake, for example, is basically a T-Rex with pyrokinesis. In fact, there is supposedly only one Dragon in Athas - the Dragon of Tyr.
But that's not quite accurate. See, Athasian Dragons are epic-leveled multiclassed psionicist-defilers who have turned their combined magical powers towards transforming into a superior state. The Dragon of Tyr is the just first psion/defiler to complete the transition, and his former compatriots, the Sorcerer-Kings, are all at some level along the transformation themselves. Indeed, becoming an Athasian Dragon is typically something an epic level character in Dark Sun could seek to do, from part of a sourcebook in 2e to a Dragon Magazine epic-level prestige class in 3e to an Epic Destiny in 4e.
Athasian Dragons, needless to say, are nasty, nasty creatures, with immense physical, arcane and psionic power at their command. In their appearances prior to 4th edition, this was somewhat counterbalanced by the extreme requirements needed to progress through the levels to become a full-fledged dragon, and by the fact that most of those levels allowed the Dungeon Master to take control of your character whenever they felt like it.
The ritual that creates the Athasian Dragon inspired the only Sorcerer-King to almost complete it, the Lich Dregoth, to believe it was humanity's ultimate destiny to transform into dragons as a species. His experiments in bringing this about led to the creation of the Dray race.
Because of course there's a monstergirl version