The Dead Lands of Athas
Life Energy and The Nature of Arcane Magic
Casting an arcane spell requires energy. The power for a spell must come from somewhere, and there are two means of fueling one’s magical endeavors on Athas. One is harsh and destructive, furthering the downward spiral of life on our world. The other is positive and beneficial, halting the effects of this ecological entropy for a while. Those who employ the first type of magic are called Defilers, while those who employ the latter variety are Preservers.
Defilers learn to draw magic from the land, but not the art of replacing it. Because it is this latter aspect of magic that is most difficult to master, they learn spells and advance in their art far more quickly than their counterparts. Defilers are a blight upon our world. They are the fiends who have destroyed Athas, and the reason that most decent folk – especially farmers and herders – will take up arms to drive any wizard, Defiler or not, from their midst.
When the life energy of foliage is converted into magical spells, the soil in which the plants were growing becomes sterile. In most cases, it stays barren for decades. The spark of life can be returned to the ground through hard work and tender care, but few people can afford to take the time required to do so.
Preservers train to control their intake of life energy, taking just what they need to cast their spells. They also seek to reinvigorate the soil after they drain it to power their spells. As Preservers learn their craft, they also learn to rekindle the spark of life. When they cast a spell, they replace what they have taken through a combination of natural and mystical processes (such as by working compost into the soil or by performing the Rite of Blood in the field they have drained). Preservers learn their spells and master their art more slowly than Defilers, for they must learn to give as well as take.
Unfortunately, Preservers are scarce compared to Defilers, and it is a rare person who understands the difference between the two. Magic is feared and reviled, and is declared illegal to practice in the major City-States unless they work personally for the Sorcerer Monarchs themselves. Defilers have a much more difficult time concealing their craft, and tread carefully within the cities.