Willpower measures a character’s inner drive
and competence at overcoming unfavorable
odds. It’s a reserve of personal strength that
characters can expend to exert themselves
forcefully. Willpower is a spendable trait (or
“pool”), but the current value is always rolled
rather than the maximum (noted on the character
sheet).
After rolling a dice pool, spend a Willpower
to reroll any or all dice used in a single roll
once, except Hunger dice (Hunger dice that
result in a 1 may not be re-rolled)
Willpower is also used to model resistances by
adding it to a relevant Attribute in situations
where your character is facing extreme stress,
terror, coercion, provocation, etc.