Anti-Divine Magic for Dungeon Fantasy

[b-dog]

In my game world there are many types of magic. Infernal magic is the magic of demons and demon lords. Evil clerics and wizards who have made pacts with demons use this magic. Wizardly magic is the free magic used by wizards and Divine magic is the magic used by good clerics. Anti -Divine magic is when a spell caster is able to override the energies of the Divine and then twist them in such a a way as to be able to use Sanctity to be able cast the spells they want. Usually the spell caster using Anti-Divine magic is a false prophet or even a false god. They use Sanctity but it is much harder to cast and far more costly as far as energy reserves go. But the magic detects as good even though the actual spell might cause evil. The Anti-Divine spell caster is usually an evil cleric or other times it may be a cultist to an Elder God trying release their Elder god from his banishment. The Anti-Divine spell caster is particularly good at releasing demons from Hell or Summoning Elder Things because bot demons and Elder Things are restricted from the mortal realm by Divine energies so Anti-Divine spellcasters can weaken this Divine protection and allow evils to enter the world. They use holy Sanctity just like good clerics do but they are able to pervert and corrupt it into powering their spells.

[Dalin]

Interesting idea. How do you manage it mechanically? Just an additional FP cost?