Corrupt Magic
aka Sanctified Magic

I know what you're thinking: anything called Corrupt Magic must be an intrinsically evil act. This is not the case, and these ancient magics might be more popular in places such as the Great Dark on Iourn. Corrupt spells exert a price, but the price is not paid in taint. Corrupt magic was first introduced in the Book of Vile Darkness, further spells were published in Heroes of Horror and (for the hell of it) the d20 Call of Cthulhu game. I have a list of 136 corrupt spells, and although have altered a few of the mechanics of corrupt magic, but the spirit of it remains the same. This list is currently available to players. It will appear on the site eventually.

Most sages believe that corrupt magic is simply a list of exceedingly evil spells that, in exchange for foul power, take a terrible toll on the caster. They are, in fact, far more than that. Corrupt magicks (and indeed sanctified magic from the Book of Exalted Deeds) are truly ancient practices. In fact they come from a time before there was a magical weave. This means they have to draw their power from another source entirely.

Here's what you need to know:

• Corrupt spells are supernatural effects. This means they do not draw power from the weave. As supernatural effects, corrupt spells are invisible to detect magic spells, they cannot be dispelled and they automatically penetrate spell resistance. Some powerful magic such as true seeing can detect them, and spells like antimagic field and Mordenkainen's disjuncture can still disrupt them.
  
  
• Any spellcaster that prepares spells in advance (notably wizards) can prepare and cast corrupt spells as they can any other spell. Spontaneous casters can cast corrupt spells from a scroll, or take the Corrupt Arcana feat from Heroes of Horror that lets them cast corrupt spells as they do the rest of their magic. Alternatively, they can cast the corrupt spell as an incantation (read on).
  
  
• Although certain spell casters can prepare corrupt spells as they can their normal magic, all corrupt spells can also be cast as incantations. Rules for incantations appear on pp 174-178 of Unearthed Arcana. Briefly, incantations can be cast by anyone - including non spellcasters. The process of casting an incantation is complicated and lengthy; it can also go spectacularly wrong.
  
  
• The power to generate a corrupt spell comes from the caster. All corrupt spells draw power away from the physical or mental well-being of the caster in the form of ability damage or ability drain (e.g. 1d6 points of Intelligence drain). The drain occurs when the spell's duration expires, unless the duration is permanent in which case it occurs directly after the spell is cast. If the loss is ability drain rather than ability damage, the lost attribute points can be restored normally: either over time or with a restoration-type spell.
  
  
• A caster must have sufficient attribute points to cast the spell. If their points are insufficient then they lose all the points in the given attribute, suffer the requisite fate and the spell fails to activate. Some corrupt spells demand a hefty toll indeed. The corruption cost for the Call Deity corrupt spell is 6d6 points of wisdom drain.

Although corrupt spells do not confer taint themselves, if you cast a corrupt spell with evil intent you may still gain taint that way (see the 'Deeds Most Foul' table in the taint section). On the whole, corrupt magic is presents a safer alternative for arcane casters in the Great Dark as long as they have some form of restoration magic at hand. It is unlikely that even the most powerful casters would be able to cast a succession of corrupt spells without incapacitating or killing themselves.