Midnight at the Oasis
Dragon of Tyr
The single most powerful being in Athas, the Dragon of Tyr is feared by all, from the lowliest slave to the mightiest sorceror-king. The Dragon swoops in periodically to demand tribute, claiming its tithe of slaves and treasure and flying off into the desert with them. It feels neither fear nor doubt, and it kills, steals, and destroys what it wants, when it wants.
If anyone alive knows the origins of the Dragon, they are not telling; the sorceror-kings might know, but they are jealous with their knowledge, and even if they do know, they still fear the Dragon more than each other. Similarly, no one knows where the Dragon makes its home, and though it almost certainly has a treasure horde that dwarfs entire city treasuries, few would be foolish enough to try to steal it.