The higher a being's Will, the less likely that it will be affected by an enchantment cast on it. Beings that are magical in some way (such as elves or sirens), magic-users, and those that are not natural tend to have higher Will than other creatures.
Monster willpower is partly based on hit dice, so monsters with high hit dice tend to be strong-willed. Most monsters with one hit die have a 50% chance to fail to resist enchantments outright, in addition to the normal saving throw. Finally, some monsters have unshakeable will and are outright immune to magical enchantments, such as most nonliving creatures.
Some of these effects can come from potions, weapon brands, clouds, or spells that are not considered enchantments.
- Brain Feed
- Cause Fear
- Confusing Touch
- Dimension Anchor
- Dispersal (confuse + teleport only)
- Enfeeble (daze + blindness only)
- Ensorcelled Hibernation
- Inner Flame
- Mass Confusion
- Scroll of fear
- Sentinel's Mark
- Sleep (but not the effects of Dream Dust from dream sheep)
- Strip Willpower (ignores Will 33% of the time)
- Teleport Other
- Wand of mindburst
- Wand of charming
- Wand of paralysis
- Wand of polymorph
- Many of these enchantments can be resisted via other means. For example, undead, nonliving, and plant monsters cannot be put to sleep.
- Polymorph will not be resisted by (very) ugly things, which will always change color. shapeshifters can only resist it if they are currently in the form of something with unshakeable will.
- Effects produced by the chaos brand don't check Will.
If (1d100 + 1d101) is less than (102 + Will - enchantment_power), the enchantment is resisted.
This is sometimes referred to as a "saving throw", after the die-based resistance system employed in Dungeons & Dragons.
(willpower) ≥ (enchantment power + 99), then the enchantment is always resisted. If
(enchantment power) ≥ (willpower + 100), then the enchantment always succeeds.
When a player casts a spell or evokes a wand, the game uses enchantment power, which is based off spell power and the type of spell cast.
First, spellpower is modified by
spellpower * factor, which is specific to a given spell. For example, Cause Fear and other "mass enchantments" have a factor of 3/2. The usual spell has a multiplier of 1. Your adjusted power is then passed through a stepdown function,
35 * log2(1 + adj_pow/35).
The stepdown function means that, for every 35 enchantment power, the next 35 power requires twice as much spellpower to obtain. Since spellpower (for spells) goes through a stepdown of its own, it becomes very hard to raise power at high levels. To compensate, many high-level spells, such as Agony and Enfeeble, have large multipliers.
For monsters, enchantment power is either 1. a flat number, or 2. a number based on monster hit dice.
After enchantment power is calculated, it is compared to the target's willpower (see above for more details).
Neither the player's nor monster's Will is ever given explicitly. A rough suggestion of how resistant they are can be seen by pressing the % key for the player, and examining a monster's description. You can also calculate the exact willpower of the player.
Pluses on these screens correspond to the Will level of the player or monster, as follows:
|Pluses shown||Player Will||Monster Will|
|+++++||200||161 or more|
As a practical matter, a player who has Will++++ should generally be able to resist the most dangerous enchanters in the game (such as deep elf demonologists, liches, and ancient liches). More Will reduces the likelihood of these spells landing even further, but the gains become significantly less important beyond this point.
A player's innate willpower is determined by the following equation:
Experience level × racial multiplier
Racial multipliers are as follows:
|Will per XL||Species|
|6||Felid, Purple draconian|
|5||Meteoran, Mummy, Naga, Vine stalker|
|4||Deep elf, Demigod, Formicid, Ogre, Vampire|
|3||All other species|
The following sources can add (or subtract) to your willpower:
- +40 for each source of Will+
- +80 when using Trog's Hand
- -80 with an orb of guile
Willpower is capped at 200 at this stage. Then, willpower is modified by the following factors (in order):
- The total is then divided by two if you are under the Will/2 status (from a scroll of vulnerability, the attack of a phantasmal warrior or imperial myrmidon, the Strip Willpower spell, or while in Tartarus).
- The robe of Folly sets your willpower to 0.
- Shadow Form gives infinite willpower.
- Prior to 0.30, willpower was not capped at 200 (Will+++++).
- Prior to 0.26, willpower was called magic resistance (MR).
- Prior to 0.13, Blink Other was subject to magic resistance.