Defiling is one of the two forms of arcane magic. Defiling, unlike Preserving, shows a lack of concern for the effects of magic, and destroys the natural life around it. Whenever a defiling spell is cast, plants wither and die, people and animals are wracked with pain, and the ground dries into an infertile dust. However, because defiling is less restricted than preserving, defiling mages can progress faster in their power.
(Because of the pain of defiling, each being surrounding the mage during the casting reduces their Initiative count by the level of the spell.)
Defilers are responsible for turning Athas into a desert, and are hated far and wide. They have created a stigma around arcane magic, and preservers are also persecuted for this sake.
The most powerful defilers are the Sorcerer Kings.