Cancel Fatigue: Any time you would suffer fatigue[...] you can spend a Conviction point and reduce the amount of fatigue by one level (so you're only winded by a fatigued result, fatigued by an exhausted result, etc).
It's the part in parentheses that make it sound like Fatigue saves should work like Toughness saves, where the amount you fail your save determines the severity of the Fatigue result.
So how do you folks do Fatigue saves in your game?
-KyleC

