Willpower

Magic resistance (MR) is the ability to resist hostile enchantments such as Slow, Confusion, Banishment to the Abyss and Disintegration.

The higher a being's MR, 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 non-natural tend to have higher MR than other creatures.

Monster MR is partly based on hit dice, so monsters with high hit dice tend to be highly resistant to magic. Most monsters with one hit die have a 50% chance to fail to resist outright, in addition to the normal saving throw. Finally, some monsters are outright immune to magical enchantments – for instance, most nonliving creatures.

Resistible enchantments

Some of these effects can come from potions, weapon brands, clouds, or spells that are not considered enchantments.

• Slow, Wand of slowing
• Wand of paralysis
• Confuse, Confusing Touch, Mass Confusion, Wand of confusion (but not Alistair's Intoxication)
• Teleport Other, Wand of teleportation
• Polymorph Other, Wand of polymorph other
• Enslavement, Wand of enslavement, Crusade card
• Banishment, Damnation card
• Cigotuvi's Degeneration, Vitriol card
• Enslave Soul
• Agony
• Pain
• Wand of disintegration
• Blink Other
• Petrify
• Corona
• Porkalator
• Ensorcelled Hibernation, Metabolic Englaciation
• Berserk
• Sleep
• Inner Flame
• Cause Fear, Scroll of fear, Banshee card
• Control Undead

Notes

• Many of these enchantments can be resisted via other means. For instance, life protection counters the effects of pain. Undead, nonliving, and plants cannot sleep.
• Polymorph will not be resisted by (very) ugly things, which will always change color.
• Polymorph cast on the player is not resisted by MR – only by mutation resistance.

Saving throws

Resisting an enchantment is dependent on the resisting creature's MR and the spell power of the enchantment it is resisting. The formula is:

If 1d100 + 1d101 is less than 102 + MR - the spell's power, the enchantment is resisted.

This is sometimes referred to as a "saving throw", after the die-based resistance system employed in Dungeons & Dragons.

Resistance descriptions

Neither the player's nor monster's MR is never given explicitly, but a rough suggestion of how magic resistant they are can be seen by pressing the @ key for the player, and examining a monster's description.

Magic resistance adjectives are as follows:

MR description	MR number
not resistant	<10
slightly	10-29
somewhat	30-59
quite	60-89
very	90-119
extremely	120-149
extraordinarily	150-189
incredibly	190-239
uncannily	240-299
almost entirely	>=300

Player resistance

As a practical matter, "extraordinarily resistant" is enough to completely resist most dangerous enchanters in the game (such as Kirke, deep elf demonologists, and even ancient liches).

Player resistance is determined as below:

Experience level * racial multiplier plus the following:

• randart MR
• 30 for each armor of magic resistance
• 40 for each ring of magic resistance
• level of MR mutation * 30
• 50 if in lichform
• 70 when using Trog's hand
• Everything is divided by two, if the player is under the effect of a scroll of vulnerability

Racial multipliers are as follows:

• 7: spriggan
• 6: purple draconian, deep dwarf, felid
• 5: naga, mummy
• 4: elves, mountain dwarf, demigod, vampire, demonspawn, ogre
• 3: humans and every other race

History

In 0.13 Phantasmal warriors can apply the effect of a scroll of vulnerability with their melee attacks.