Mettle
From NsdWiki
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 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.