The World of Athas is a desert planet where the most powerful beings in all of the AD&D world roam. The PC ability scores range from 2-24, as opposed to the normal 2-19. All characters have wild psionics. There are a vast amount of races, ranging from the half-giant to the 2 foot halfling, and aracocra (bird people) to the thri-kreen (insectoids with 4 arms). There are some powerful classes, like the gladiator, proficient in all (non-exotic) weapons, to the Templars, (priest) enforcers of the sorcerer kings. The only disadvantage that an Athasian faces is metal; metal costs ten times as much as nonmetal items. The main currency here is ceramic(=copper) pieces, not gold.
The original boxed set included seven major cities, with smaller cities outside, each controlled by a sorcerer-king, who had the power to grant priest spells to their templars.
In the revised set, set after the Prism Pentad, includes the updated Athas, with thri-kreen and elven kingdoms, and more cities. Few of the sorcerer-kings survived, so there are few templars.
This is a great world. It and Birthright are the two most popular AD&D worlds out there. Why? Because people like being ultra-powerful. It is my opinion that this is the only world suitable for psionics, as it is built around them. (I have a personal grudge against psionics, even with the revised rules presented in the Skills and Powers book.)
I would highly recommend reading the Prism Pentad, by Troy Denning, as it is a great series, and it will inform its reader about the history of Athas.
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