Willpower

Being a measure of the Character's mental toughness and ability to resist mental influences, Willpower controls the availability of Spells and also determines a Character's aptitude for haggling, as well as his or her resistance to the effects of certain Spells and Skills.
Willpower also contributes to the Character's Hit Points, and has an impact on his or her level of fatigue.
A strong Will allows a Character to ignore some small measure of suffering, be it physical damage or sheer exhaustion.
The abbreviation for Willpower is given as "WP".
Derived Statistics: 
Hit Points: Each point spent on willpower grants the character a +1 HP. 
Fatigue: Each point of willpower grants a +1 FT.