Grimrock

Well the title says it all. That's what I want to do.
I already know how to edit monsters.lua but, I am not sure what line to add to change their damage type.
I am assuming that the damage types are the same as the immunities for the most part.

I've never done this, but I think the best thing to try is to create a onDealDamage hook in the monster definition and add a champion:damage(amount, type) script to it.