Fire resistance? Fire damage immunity? :-) Obviously the fiery pain changed... and it was literal fiery pain :-)

I don't know whether or not it already happens, but the pains arising due to not being C should be chaotic in nature. That is, either they should be a different element with each turn, or change element after some random number of turns.

So, it could be fiery pain in the stomach at one point in time, like a shock to the heart at another, like something eating away at the lungs at a third time, and like the most severe cold headache at a fourth time (descriptions intended to give ideas, rather than being literal).

Then, more resistances/immunities would result in less damage from the effect.

Should I make an RFE for this?

EDIT: Or, if that's too complex, choose the element type that is least used in the game, and make it that one, so that it adds value to having resistance to that element. Fire is the most common element, it's a bit boring.

While that thematically makes sense, I think it would make any ending other than "stupid follower" really really difficult for CKs. I vote to leave the pains as they are.