The Willpower skill reduces the chance of being Feared, Muted, Charmed, Stunned, Cursed, Slowed, Petrified, Decaying Touched, Mark of Deathed, Remorsed, and Shackles of Pained. This is very important for melee characters, as they are the most likely to be the target of crowd control. Ranged characters may want to invest a point or two as well, as fears and stuns are often area-of-effect environmental hazards that you can't avoid even with the best positioning.
|Willpower Skill Level||Chance reduction|
For a skill / spell that has a Willpower defense, Willpower affects the success chance of any harmful effect the skill applies. Other values, like damage, are not affected. More specifically, if WP is the Willpower of the spell target, the success chance of the effect is multiplied by:
1 – 0.15 * WP (or 100% - 15% * WP). Here is an example:
Let's say a wizard with INT 15 is trying to stun an enemy fighter using the Shocking Touch spell. This spell has an 80% base success chance and INT will raise it to 115% (see the skills page).
On the other side, let's say the fighter’s Willpower is 3. This means that the success ratio of the effect is limited by a 1 – 0.15 * 3 = 0.55 factor.
The overall success chance of the Freezing Touch spell is the product of the two figures above, which is 115% x 0.55 = 63% (rounded). So the fighter finally has a 100 - 63 = 37% chance to avoid to get stunned. This last figure is reported in the statistics window at the bottom right corner of the screen (maybe +/- 1 because of rounding).