Glimpses of Hyboria
Any time a character comes into contact with a demon, evil god or unusually powerful and corrupt sorcerer except in the context of actively attacking it or fleeing from it in terror, he must make a corruption saving throw. This is a Will save.
A character’s current Corruption is applied as a penalty to all corruption saving throws.
A failed Corruption save gives the character 1 point of Corruption.
Insanity: Each time an already corrupt sorcerer successfully saves vs. Corruption, he must make a second Corruption save at the same DC as the first. Failure causes him to become shaken for 1d6 rounds and to gain a permanent minor insanity (see GM).
A sorcerer who already has a minor insanity and fails a second insanity saving throw becomes shaken again for 3d6 rounds and gains a permanent major insanity. See GM.
Sorcerers can recover from Insanity by avoiding magic for three months and making will saves of 15 and 20 for minor and major insanities. A sorcerer may only recover from one insanity per three month hiatus.