[DF] Devil power help

[Humabout]

Originally Posted by b-dog

I have another idea that is sort of the Black Magic rule for all of the PCs. The Devil is active in my campaign and likes to tempt the PCs with powers and other enticements. The Devil wants the souls of men and having man choose evil makes things much better. So the Devil will likely offer assistance to PCs in their time of need for a small price of course. The PC will gain some power or make a die roll or be able to escape some danger in exchange for a very small part of his soul. This might add a black point like on black magic rules. When the PC has enough black points then the soul of the PC belongs to the Devil and the PC is out of the players control.

You might look up the corruption system in GURPS Horror. It provides a rather nice approach to gradually changing a person's personality until they are consumed by an idiology. It shouldn't be difficult to adapt, since you coudl base corruption costs on a percentage of the equivalent advantage granted by the devil (or negated disadvantage, should that be the nature of the devil's help).