Magic resistance (monster) - Revision history

Umbire the Phantom: /* List of effects subject to monster magic resistance */ bit of copyedit

2026-03-16T21:36:35Z

‎List of effects subject to monster magic resistance: bit of copyedit

Umbire the Phantom: typo

2026-03-15T13:49:16Z

typo

Umbire the Phantom: some copyedit

2026-03-15T13:49:08Z

some copyedit

Umbire the Phantom: potholes

2025-07-10T09:57:21Z

potholes

Umbire the Phantom: pothole

2025-07-10T08:21:03Z

pothole

Umbire the Phantom: some potholes

2025-07-04T07:52:12Z

some potholes

Cathartes: nethack-367

2024-12-22T02:48:40Z

nethack-367

Cathartes: correction: healing is against Pestilence; also change example given in Strategy section

2024-12-22T02:47:40Z

correction: healing is against Pestilence; also change example given in Strategy section

Cathartes: /* List of effects subject to monster magic resistance */ add list

2024-12-22T02:41:19Z

‎List of effects subject to monster magic resistance: add list

Cathartes: /* Strategy */ todo - use a better example

2024-12-11T06:25:27Z

‎Strategy: todo - use a better example

@@ Line 41: / Line 41: @@
 All this also determines the chance that monsters (including [[pet]]s) resist conflict; conflict from the [[Sceptre of Might]] is treated the same as the [[ring of conflict]] for this purpose.
-===List of effects subject to monster magic resistance===
+===Effects subject to monster magic resistance===
-Unless otherwise specified, monster magic resistance completely prevents effects.  Some exceptions cause monsters to take less damage instead of nullifying it completely.
+Monster magic resistance is used in determining the outcomes of the following effects, including whether or not any damage inflicted from these effects is halved:
 * The scaring effect of [[Magicbane]]{{refsrc|src/artifact.c|1076|nethack=3.6.7}}
@@ Line 48: / Line 48: @@
 * [[Explosion]]s (halves damage){{refsrc|src/explode.c|425|nethack=3.6.7}}
 * All sources of [[sleep]]ing{{refsrc|src/mhitm.c|1512|nethack=3.6.7}}
-* [[Wand of striking]] and [[force bolt]] (halves damage){{refsrc|src/zap.c|5210|nethack=3.6.7|comment=damage is done directly inside the <code>resist()</code> function, and halved if resisted|name=resist_halfdamage}}{{refsrc|src/muse.c|1270|nethack=3.6.7}}{{refsrc|src/zap.c|175|nethack=3.6.7}}
+* [[Wand of striking]] and [[force bolt]] (halves damage){{refsrc|src/zap.c|5210|nethack=3.6.7|comment=damage is done directly inside the <tt>resist()</tt> function, and halved if resisted|name="strikeforce"}}{{refsrc|src/muse.c|1270|nethack=3.6.7}}{{refsrc|src/zap.c|175|nethack=3.6.7}}
 * The scaring effect of [[tooled horn]], [[drum of earthquake]], [[leather drum]], and [[bugle]]{{refsrc|src/music.c|79|nethack=3.6.7|comment=for horns and drums}}{{refsrc|src/music.c|205|nethack=3.6.7|comment=for bugles}}
 * The taming effect of [[magic harp]], [[scroll of taming]], or [[spellbook of charm monster]]{{refsrc|src/music.c|230|nethack=3.6.7}}{{refsrc|src/read.c|944|nethack=3.6.7}}

@@ Line 1: / Line 1: @@
 {{tocright}}
-{{otheruses|the measure of a monster's magical defenses|the property that blocks [[magic missile]]s and [[force bolt]]s|magi resistance}}
+{{otheruses|the measure of a monster's magical defenses|the property that blocks [[magic missile]]s and [[force bolt]]s|magic resistance}}
 In ''[[NetHack]]'', '''monster magic resistance''', also known as '''monster MR''' or '''MR score''', is a numeric value that determines the ability of a [[monster]] to resist the effects of magic such as [[spellcasting]], [[zapped]] [[wand]]s and [[thrown]] [[potion]]s.

@@ Line 1: / Line 1: @@
-In ''[[NetHack]]'', monsters have some degree of innate '''magic resistance''', also known as '''monster MR'''. Monsters' magic resistance allows them to resist various attacks, generally of a "magical" nature. It is handled by the resist() function&mdash;if a monster successfully resists an attack, it takes roughly half damage.{{refsrc|src/zap.c|4802|nethack=3.6.0}} Players cannot ever gain monster-style resistance, e.g. through [[polymorph]], and must instead rely upon [[magic cancellation]] and [[magic resistance]].
+{{tocright}}
+{{otheruses|the measure of a monster's magical defenses|the property that blocks [[magic missile]]s and [[force bolt]]s|magi resistance}}
-Monster magic resistance is separate from the [[magic resistance]] property provided by various worn or carried [[item]]s, which some monsters such as [[gray dragon]]s and [[Angel]]s also have intrinsically; this form of "player-style" magic resistance does not affect [[taming]] and [[conflict]], but renders [[polymorph trap]]s ineffective. Neither type of magic resistance will protect monsters from level teleporters.
+In ''[[NetHack]]'', '''monster magic resistance''', also known as '''monster MR''' or '''MR score''', is a numeric value that determines the ability of a [[monster]] to resist the effects of magic such as [[spellcasting]], [[zapped]] [[wand]]s and [[thrown]] [[potion]]s.
 ==Description==
-MR is given as a number from 0 to 100. This is frequently given as a percentage, although this is not entirely accurate. The chance of a monster resisting is given as follows:
+A monster with a magic resistance score higher than 0 has a chance of taking halved damage when subjected to certain magical items and effects by a [[hero]] or another monster.{{refsrc|src/zap.c|5159-L5223|nethack=3.6.7|comment=<tt>resist()</tt> function}} A monster's MR score also determines the chance that it resists the effects of [[conflict]], [[taming]] and being [[polymorph]]ed, e.g. by a [[polymorph trap]].{{refsrc|src/trap.c|2682|nethack=3.6.7|name="polytrap"}} This chance is given as follows:{{refsrc|src/zap.c|5204|nethack=3.6.7}}
-  Chance = MR/(100 + (attack level) - (defense level)){{refsrc|src/zap.c|4842|nethack=3.6.0}}
+  Chance = MR/(100 + (attack level) - (defense level))
-which is only equal to MR as a percentage when attack and defense level are equal. Zero MR monsters will never resist.
+Monster magic resistance is distinct from the [[magic resistance]] property (sometimes referred to as "player-style MR"): the latter does ''not'' affect a monster's resistance to conflict and taming effects, but does protect them from polymorphing as well as [[wands of striking]], [[force bolt]]s, [[wands of death]], rays from a {{+ of|finger of death}}, and all forms of [[magic missile]]s{{refsrc|src/trap.c|2680|nethack=3.6.7|comment=polytrap check for magic resistance property}}&mdash;neither type of magic resistance will protect monsters from [[level teleporter]]s. Monster magic resistance is also different from [[magic cancellation]], which can block some of the secondary effects of direct monster attacks such as the [[level drain]] from a [[wraith]]'s [[touch attack]], and is applicable to both heroes and monsters (e.g. by wearing [[armor]]).
-Attack level is calculated as follows, where the defense level is the [[monster level]] of the target, which has a maximum of 50:
+===Attack and defense level===
 {|class="prettytable"
@@ Line 16: / Line 17: @@
 ! Attack level
 |-
-| [[spellcasting|spell]]
+| [[Spellcasting|spell]]
 | Caster's level
 |-
-| [[wand]], [[polytrap]]{{refsrc|src/trap.c|2588|nethack=3.6.0}}
+| [[Wand]] or [[polymorph trap]]{{refsrc|src/trap.c|2588|nethack=3.6.0}}
 | 12
 |-
-| [[tool]]
+| [[Tool]]
 | 10
 |-
-| [[weapon]]
+| [[Weapon]]
 | 10
 |-
-| [[scroll]]
+| [[Scroll]]
 | 9
 |-
-| [[potion]]
+| [[Potion]]
 | 6
 |-
-| [[ring]]
+| [[Ring]]
 | 5
 |}
@@ Line 40: / Line 41: @@
 All this also determines the chance that monsters (including [[pet]]s) resist conflict; conflict from the [[Sceptre of Might]] is treated the same as the [[ring of conflict]] for this purpose.
-==List of effects subject to monster magic resistance==
+===List of effects subject to monster magic resistance===
 Unless otherwise specified, monster magic resistance completely prevents effects.  Some exceptions cause monsters to take less damage instead of nullifying it completely.
@@ Line 56: / Line 57: @@
 * [[Turn undead]] &ndash; one check each for scaring, and pacifying or killing{{refsrc|src/pray.c|2023|nethack=3.6.7}}{{refsrc|src/pray.c|2023|nethack=3.6.7}}
 * The scaring effect when reading [[scroll of scare monster]] or casting [[cause fear]]{{refsrc|src/read.c|1250|nethack=3.6.7}}
-* [[Polymorph trap]]{{refsrc|src/trap.c|1639|nethack=3.6.7}}{{refsrc|src/trap.c|2682|nethack=3.6.7}}
+* Stepping onto a polymorph trap{{refsrc|src/trap.c|1639|nethack=3.6.7}}<ref name="polytrap"/>
 * Confusion when hitting while charged from [[scroll of confuse monster]] or {{+ of|confuse monster}}{{refsrc|src/uhitm.c|1323|nethack=3.6.7}}
 * Slowing from [[wand of slow monster]] or {{+ of|slow monster}} spell{{refsrc|src/zap.c|182|nethack=3.6.7}}
@@ Line 71: / Line 72: @@
 ==Messages==
-{{message|<[[Foo]]> resists!|A monster resisted an attack; this is shown only in some cases.}}
+{{message|<The monster> resists!|A monster resisted an attack; this is shown only in some cases.}}
 ==Variants==

@@ Line 57: / Line 57: @@
 * The scaring effect when reading [[scroll of scare monster]] or casting [[cause fear]]{{refsrc|src/read.c|1250|nethack=3.6.7}}
 * [[Polymorph trap]]{{refsrc|src/trap.c|1639|nethack=3.6.7}}{{refsrc|src/trap.c|2682|nethack=3.6.7}}
-* Confusion when hitting while charged from [[scroll of confuse monster|scroll]] or [[spell of confuse monster]]{{refsrc|src/uhitm.c|1323|nethack=3.6.7}}
+* Confusion when hitting while charged from [[scroll of confuse monster]] or {{+ of|confuse monster}}{{refsrc|src/uhitm.c|1323|nethack=3.6.7}}
 * Slowing from [[wand of slow monster]] or {{+ of|slow monster}} spell{{refsrc|src/zap.c|182|nethack=3.6.7}}
 * Hasting from [[wand of speed monster]]{{refsrc|src/zap.c|195|nethack=3.6.7}}

@@ Line 58: / Line 58: @@
 * [[Polymorph trap]]{{refsrc|src/trap.c|1639|nethack=3.6.7}}{{refsrc|src/trap.c|2682|nethack=3.6.7}}
 * Confusion when hitting while charged from [[scroll of confuse monster|scroll]] or [[spell of confuse monster]]{{refsrc|src/uhitm.c|1323|nethack=3.6.7}}
-* Slowing from [[wand of slow monster|wand]] or [[spell of slow monster]]{{refsrc|src/zap.c|182|nethack=3.6.7}}
+* Slowing from [[wand of slow monster]] or {{+ of|slow monster}} spell{{refsrc|src/zap.c|182|nethack=3.6.7}}
 * Hasting from [[wand of speed monster]]{{refsrc|src/zap.c|195|nethack=3.6.7}}
 * Scaring from [[wand of undead turning]] or {{+ of|turn undead}} {{refsrc|src/zap.c|218|nethack=3.6.7}}

@@ Line 60: / Line 60: @@
 * Slowing from [[wand of slow monster|wand]] or [[spell of slow monster]]{{refsrc|src/zap.c|182|nethack=3.6.7}}
 * Hasting from [[wand of speed monster]]{{refsrc|src/zap.c|195|nethack=3.6.7}}
-* Scaring from [[wand of undead turning]] or [[spell of turn undead]]{{refsrc|src/zap.c|218|nethack=3.6.7}}
+* Scaring from [[wand of undead turning]] or {{+ of|turn undead}} {{refsrc|src/zap.c|218|nethack=3.6.7}}
-* Polymorph from [[wand of polymorph|wand]], [[spellbook of polymorph|spell]], or [[potion of polymorph]]{{refsrc|src/zap.c|235|nethack=3.6.7}}
+* Polymorph from the [[wand of polymorph|wand]], [[spellbook of polymorph|spell]], or [[potion of polymorph]]{{refsrc|src/zap.c|235|nethack=3.6.7}}
-* Damage received by [[Pestilence]] from [[spell of healing]] or [[spell of extra healing]] (halves the amount of damage instead of nullifying it){{refsrc|src/zap.c|394|nethack=3.6.7}}
+* Damage received by [[Pestilence]] from {{+ of|healing}} or {{+ of|extra healing}} spells (halves the amount of damage instead of nullifying it){{refsrc|src/zap.c|394|nethack=3.6.7}}
 * Spell of {{+ of|drain life}} (resistance halves damage and prevents level drain)<ref name=resist_halfdamage/>{{refsrc|src/zap.c|438|nethack=3.6.7}}
-* [[Cancellation]] from [[Magicbane]], [[wand of cancellation]], and [[spell of cancellation]] {{refsrc|src/zap.c|2741|nethack=3.6.7}}
+* [[Cancellation]] from [[Magicbane]], [[wand of cancellation]], and {{+ of|cancellation}} spell {{refsrc|src/zap.c|2741|nethack=3.6.7}}
 * Damage from [[ray]] hits (halves damage){{refsrc|src/zap.c|3753|nethack=3.6.7}}

@@ Line 90: / Line 90: @@
 ==References==
 <references/>
-{{nethack-360}}
+{{nethack-367}}
 [[Category:Monster attributes]]

@@ Line 50: / Line 50: @@
 * The scaring effect of [[tooled horn]], [[drum of earthquake]], [[leather drum]], and [[bugle]]{{refsrc|src/music.c|79|nethack=3.6.7|comment=for horns and drums}}{{refsrc|src/music.c|205|nethack=3.6.7|comment=for bugles}}
 * The taming effect of [[magic harp]], [[scroll of taming]], or [[spellbook of charm monster]]{{refsrc|src/music.c|230|nethack=3.6.7}}{{refsrc|src/read.c|944|nethack=3.6.7}}
-* The maximum and current HP halving effects (one check for each) when hit by [[potion of sickness]] (or healing potions for [[Famine]]){{refsrc|src/potion.c|1457|nethack=3.6.7}}
+* The maximum and current HP halving effects (one check for each) when hit by [[potion of sickness]] (or healing potions for [[Pestilence]]){{refsrc|src/potion.c|1457|nethack=3.6.7}}
 * The confusion effect when hit by potion of {{! of|confusion|or=1|booze}}{{refsrc|src/potion.c|1468|nethack=3.6.7}}
 * The blinding effect when hit by [[potion of blindness]] (blindness duration is increased by fewer turns, instead of being nullified){{refsrc|src/potion.c|1502|nethack=3.6.7}}
@@ Line 68: / Line 68: @@
 ==Strategy==
-Monster magic resistance generally determines what strategies are effective against certain monsters - for example, the [[Riders]] have complete monster magic resistance, but {{monsymlink|Pestilence}} and {{monsymlink|Famine}} can be subjected to [[level drain]], making it possible for magical effects to work on them if their level is drained enough; {{monsymlink|Death}} is completely resistant to drain life.
+Monster magic resistance generally determines what strategies are effective against certain monsters - for example, [[mind flayer]]s have 90 monster magic resistance, which makes strategies such as polymorph magic or scaring from a musical instrument unlikely to work.  In contrast, these strategies will work on [[minotaur]]s, which have no monster magic resistance.
 ==Messages==