FormerlyHemlock
Hero
One of my favorite things about mind flayers has always been the way they shrug off spells with near-total impunity.
Unfortunately in 5E, that's no longer true. "Magic Resistance" now gives advantage on saves, but with their pathetic Dex +1/Con +1 saves, Mind Flayers die to Fireballs and Magic Missiles just as easily as everything else.
Now of course you could just port in MR% wholesale and declare that Mind Flayers have a 90% chance to ignore/collapse any spell, and I've considered doing so, but somehow it just doesn't feel right for the 5E idiom. How do you model a creature which shrugs off magic, while staying within the idiom?
Draft Proposal: Magic Immunity
Description: Magic Immunity is not true immunity, but the creatures which possess it have a terrifying reputation for impossible resilience to magic and resisting things that should not be resisted. Magic slides off them like water off a duck's back, and as far as the average magic-user may know, spellcasting is utterly futile against them.
Rules: Creatures with Magic Immunity gain advantage on saves vs. all spells and other magical effects (as determined by the DM, but may include Basilisk gazes, Banshee wails, monk's Stunning Strikes, perhaps even cleric turning, depending on campaign). Additionally, a creature with Magic Immunity may expend its reaction to add its proficiency bonus to its saving throw against a spell or magical effect, or to add its proficiency bonus to its AC against a spell or magical effect. It may do so after the d20 is rolled but before the DM declares the result. A creature with Magic Immunity always possesses the Avoidance trait (like a demilich): any spells which offer a saving throw for half damage instead does no damage on a successful save and half damage on a failed save.
Additionally, a creature with Magic Immunity gains the Ignore Magic action. When a creature Ignores Magic, any single-target spells cast directly on the creature end (such as Suggestion or Maze), and it is unaffected by all spells and magical effects, as if it were in an Antimagic Field (see spell), until the beginning of its next turn. Spells do not affect it, summoned creatures are unable to harm it directly, magic items do not function for or against it. (As with Antimagic Field, artifacts and deific magic are not subject to Ignore Magic.)
Magic Immunity affects CR as follows: increase effective AC by one plus the creature's proficiency bonus. Remember that +4 to effective AC equates to +1 CR.
Implications and Usage: Magic Immunity should be used sparingly, as a way for creatures to do the impossible. Imagine a Mind Flayer shrugging off lightning bolts and then, when sequestered behind a Wall of Force, waiting until the PCs turn their attention away and then eerily stepping through the Wall of Force as if it weren't even in the same dimension! Imagine an ancient dragon against whom Eldritch Blast seems to dissipate without effect, although an enchanted arrow will bring it down.
The rules above aim to capture the feel of old-school MR%, but they aren't an exact translation. A Maze spell or Wall of Force will still take a Mind Flayer out of play for at least a round; a Hold Monster spell from a sufficiently-powerful mage has a good chance to overcome its immunity by virtue of a high spell DC, and Ignore Magic will be impossible because it will be incapacitated; Magic Immunity can be overcome by brute force by using up the creature's reaction; and Magic Missiles are completely unhindered by Magic Immunity because they rely on neither saves nor attack rolls. Hopefully those limitations are acceptable or even desirable.
It might be appropriate to reduce or eliminate Legendary Resistance for creatures that have Magic Immunity, since they both serve similar purposes.
Unfortunately in 5E, that's no longer true. "Magic Resistance" now gives advantage on saves, but with their pathetic Dex +1/Con +1 saves, Mind Flayers die to Fireballs and Magic Missiles just as easily as everything else.
Now of course you could just port in MR% wholesale and declare that Mind Flayers have a 90% chance to ignore/collapse any spell, and I've considered doing so, but somehow it just doesn't feel right for the 5E idiom. How do you model a creature which shrugs off magic, while staying within the idiom?
Draft Proposal: Magic Immunity
Description: Magic Immunity is not true immunity, but the creatures which possess it have a terrifying reputation for impossible resilience to magic and resisting things that should not be resisted. Magic slides off them like water off a duck's back, and as far as the average magic-user may know, spellcasting is utterly futile against them.
Rules: Creatures with Magic Immunity gain advantage on saves vs. all spells and other magical effects (as determined by the DM, but may include Basilisk gazes, Banshee wails, monk's Stunning Strikes, perhaps even cleric turning, depending on campaign). Additionally, a creature with Magic Immunity may expend its reaction to add its proficiency bonus to its saving throw against a spell or magical effect, or to add its proficiency bonus to its AC against a spell or magical effect. It may do so after the d20 is rolled but before the DM declares the result. A creature with Magic Immunity always possesses the Avoidance trait (like a demilich): any spells which offer a saving throw for half damage instead does no damage on a successful save and half damage on a failed save.
Additionally, a creature with Magic Immunity gains the Ignore Magic action. When a creature Ignores Magic, any single-target spells cast directly on the creature end (such as Suggestion or Maze), and it is unaffected by all spells and magical effects, as if it were in an Antimagic Field (see spell), until the beginning of its next turn. Spells do not affect it, summoned creatures are unable to harm it directly, magic items do not function for or against it. (As with Antimagic Field, artifacts and deific magic are not subject to Ignore Magic.)
Magic Immunity affects CR as follows: increase effective AC by one plus the creature's proficiency bonus. Remember that +4 to effective AC equates to +1 CR.
Implications and Usage: Magic Immunity should be used sparingly, as a way for creatures to do the impossible. Imagine a Mind Flayer shrugging off lightning bolts and then, when sequestered behind a Wall of Force, waiting until the PCs turn their attention away and then eerily stepping through the Wall of Force as if it weren't even in the same dimension! Imagine an ancient dragon against whom Eldritch Blast seems to dissipate without effect, although an enchanted arrow will bring it down.
The rules above aim to capture the feel of old-school MR%, but they aren't an exact translation. A Maze spell or Wall of Force will still take a Mind Flayer out of play for at least a round; a Hold Monster spell from a sufficiently-powerful mage has a good chance to overcome its immunity by virtue of a high spell DC, and Ignore Magic will be impossible because it will be incapacitated; Magic Immunity can be overcome by brute force by using up the creature's reaction; and Magic Missiles are completely unhindered by Magic Immunity because they rely on neither saves nor attack rolls. Hopefully those limitations are acceptable or even desirable.
It might be appropriate to reduce or eliminate Legendary Resistance for creatures that have Magic Immunity, since they both serve similar purposes.
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