Willpower

From The Elder Scrolls Construction Set Wiki

Description	Affects how quickly you regenerate Magicka and how much Fatigue you have.
Governs Skills	Alteration Destruction Restoration
Game Mechanics	Maximum Fatigue = Strength + Endurance + Agility + Willpower MagickaRegenRate = 0.01 * (fMagickaReturnBase + fMagickaReturnMult * Willpower) * TotalMagicka.