Sorry if this came up elsewhere, I didn't see it when I did a search check.
But would Mettle potentially trump things like Evil Eye (Witch)?
Mettle (Ex): You are able to resist effects with great willpower of fortitude. If you succeed on a Fortitude or Will save against an effect with a partial effect on a successful save, you instead suffer no effects from the attack.
A successful save vs Evil eye normally reduces the effect to 1 round, which can lead to cackle-cycling to keep things going. But with Mettle, a save that results in partial effect (would that include duration of effect) gets negated entirely. So would the Mettle saving guy be potentially immune to evil-eye stacking if they save?
Yes.