A wizard is able to capture and master magical energies. On Athas, magic and the ecosystem are irrevocably bound —no one, not even a wizard, can affect one without affecting the other.
All wizards must decide at the beginning of their careers whether they are trying to work with nature or without regard for it. In Dark Sun, if they decide to work with nature it means the wizard must be a Preserver.
The preserver attempts to use magic in concert with the environment. Learning how to wield such magic on Athas is especially difficult, so the preserver's advancement is slow. A preserver can be either a freeman or slave.
Preservers also gather energy from the land, but they take only what they need and work to keep the world healthy and alive. Preservers are mortal enemies of Defilers, stand locked in a never-ending battle -with the survival of Athas at stake.
Reviled and hunted, hated and feared, Preservers live in secrecy, hiding who and what they are from the rest of the world. They are criminals whose crime calls for swift execution. They are oucasts, with no place to call home. They are Wizards, and their crime is the practice of magic...
Beneath the crimson sun, the life of a Wizard is hard and dangerous. Blamed for the conditions of the world, feared for the mysterious power they wield, and hated for crimes both real and imagined, Athasian Wizards walk in the shadows of civilization and in the barren wastes of the wilderness. For to reveal their nature is to admit their crime —and risk their very lives.
Preservers make sure not to take more life force from plants than necessary for their spells. If they take too much they risk destroying the plants in a way that kills the plant completely. In extreme circumstances that defilement can mean that no plant life will ever grow from that spot.
- Dark Sun Boxed Set. 2nd Edition. TSR Inc.