Mettle
Typically used with: Courage.
In short: "what curse?". Mettle is a measure of temerity, fortitude, and rebellion of spirit. Mettle checks are called upon in opposition to curses and supernatural attacks. A better way to think of this skill is Guard of the spirit; a tangible supernatural toughness.
Resisting Damage
There exist spectral monsters whose vile touch can pass straight through your armor and disrupt your very life force. Creatures that have gained the incorporeal condition are able to penetrate solid objects, but only some can suck the life from you with a touch. When confronted with one of these wraiths, you must make a Dodge check to avoid their reach. If you can't avoid the attack, make a Mettle check. Your opponent makes a Might check.
Resisting Spells
Certain spells can be overcome with a Mettle check, for instance Steal Strength and Inflict Pain. In this case, Magic Defense can be added to your Mettle check.