Having more than 100% resistance to an element causes that element to heal you, which allows for some high-resistance armor to be combined with the warrior talent 'Weather the Storm' (+50 to all elemental resistance) for an awesome warrior that eats lava as a pick-me-up.

But if you take this route with Madora and heal her with some friendly fireballs, she'll take offense and permanently leave the party (after a couple times) even though she not only took 0 damage, but was actually healed.

I think it's probably an oversight; does anyone have any idea if the companion-abandon-party behavior would be editable easily? Not sure where to look in the game files or editor for something like that.