D&D 5E AD&D-style Illithid/Dragon Magic Resistance in 5E

[Warmaster Horus]

I like the idea of contested rolls. A powerful mage's magic is more likely to effect a resistant creature than a less experienced one.

 

[steeldragons]

No there are two kinds of "resistance" in the game: getting advantage on saves and taking half damage.

One does not necessarily follow the other. They often do, but they don't have to.

You are quite right. Upon a review of the material, what I was taking as "resistance" is, in fact, listed as "Resilience" (e.g. Dwarf and Stout) offering advantage and damage resistance.

Things that offer damage resistance are called "resistance", as per the dragonborn resistance to breath weapon damage type or tiefling fire resistance...both of which are called "<Something> Resistance." Traits that offer advantage on saves are, invariably on the player's side, called something else: Fey Ancestry, Gnome Cunning, and the like.

The only exception here, that I can find, is "Magic Resistance" (the topic of the thread). In which it only offers advantage to saves (and, as best I can tell, is only granted to Fey, Demons, Devils, Slaadi, the Helmed Horror, and the Death Knight) and nothing about the damage...unlike Resistance in every other place the term appears...including the monsters' stat blocks.

"Legendary Resistance" is, of course, something completely else and unrelated, mechanically, neither advantage nor damage resistance, but "auto-save" whatever the effect...and it's "Legendary", I'm not gonna argue with it.

Thus: it is perfectly alright to have "fire resistance" mean half damage from fire. Or advantage on saves from fire. Or both.

We are, apparently, both wrong here. A resistance to fire damage accompanied with advantage against fire saves, would properly be termed (according to 5e) "Fire Resilience," as the only time "Resistance" is taken to mean advantage on saves is with Magic.

So, correctly terming what I was proposing in my original post would/should be called "Magic Resilience." Mia culpa.

When it comes to magic resistance, getting advantage from spells is the default.

This is so as written. Yes. However the topic at hand and intention of the thread is to say "How do I get a AD&D type/feel for 5e Magic Resistance?"

Getting half damage from "magic" is, on the other hand, almost unheard of.

Correct and not, simultaneously, again. Because damage resistances are listed by "damage type" and the source of the type is not taken into consideration. The simplicity model of 5e, I would guess, avoiding fiddliness (e.g. "Is it magic fire or non-magic fire?") is responsible for this imminently sensible approach.

Thus, a creature such as the Specter, that is resistance to practically every damage type, immune to others, and immune to nearly all condition types, would/could reasonably be considered, within the fiction, virtually immune to all magic (along with much more). Throwing acid, fire, lightning, etc...etc... is only ever going to be half damage, at best. So, in reality/actuality, in both game and narrative terms, while not listed as "magic resistance" there are many many things that are resistant (in greater or lesser degrees) to magic via the "Damage Resistances" in their stat block...not so "almost unheard of."

[Honestly, as a complete aside, just noticing the Specters and Wraiths have the longest lists of resistances/immunities of any creature I can find. Resulting in, I am sure, "Magic Resistance" not being among their traits. Makes sense, I guess. Interesting, at least. Not really what I would expect.]

This would then be half damage against everything except non-magical attacks, which doesn't make a whole lotta sense for D&D as a game.

From another angle, it makes tons of sense, and a nearly unbeatable creature, in a "typical" D&D world. Additionally, very good for low-/no-magic/"gritty" worlds/play.

It would be silly if the fighter put down his magical greataxe and attacked with a regular stick...

This is a bit of binary ad absurdum. A "greataxe" is still going to do d12 damage, magical or not. A "stick", at best and only if one were to deem it equivalent to a "club", is getting you no more than d4. Whether a creature is immune or resistant to any magic add-ons, it's not going to negate the weapon damage. [EDIT to add: If the creature is also resistant to non-magic weapon damage, then, yeah, that'll be a tough fight/distinct disadvantage. And if it's immune to non-magical weapon damage, you're just totally screwed/better run fast and run far! /edit]

So it isn't quite as clearcut as you think it is.

No, I suppose not. Nor you, it seems. Thankfully, with a bit of common sense and rulings not rules, it can be for both of us.

TL;DR If "Magic Resistance" is the only use of the term "resistance" that doesn't halve damage...that's a flaw/mistake in the terminology. Halving the damage is a perfectly reasonable thing to do to bring the term in line with how it's used everywhere else in the game and, yes, it also makes the monsters that have it a good bit more dangerous/tough to beat...that's a feature not a bug. Especially in a game that was designed with every-blessed-character-and-its-mother having spells.

And, just to reiterate, I think "DM rolls to beat DC10 + CR [maximum 19] to see if a given spell takes effect on the creature. Round down, for things with fractional CR. " is not, at all, complex...

If you want to go very 1e and add a bit more complexity, say "+/-5% (1 point on the d20) per level of caster above/below level X" [where X=10, would be my best guess].

 

[MostlyDm]

When it comes to magic resistance, getting advantage from spells is the default. Getting half damage from "magic" is, on the other hand, almost unheard of. This would then be half damage against everything except non-magical attacks, which doesn't make a whole lotta sense for D&D as a game. It would be silly if the fighter put down his magical greataxe and attacked with a regular stick...

So it isn't quite as clearcut as you think it is.

It's definitely way less common, but it does crop up.

At minimum, Abjurer PCs get this at 14th level (they get both advantage on saves vs magic AND half damage from magic), Oath of Ancients Paladins get it, and the Archmage NPC in the MM gets it.

Though to be clear, in these cases it's not half damage from all nonmagic attacks, it's half damage from spells. Magic weapons and similar stuff still works against them.

 

[MostlyDm]

I love the simplicity of Zardnaar's idea, converting the % to a more appropriate "feel" d20 roll. But I fear it's too rough... 1e had a sort of checks and balances system, where wizards were gods except when they weren't. 5e has a bit of 4e sensibility in that it tries harder for everyone to be able to contribute. A monster with MR 19 might basically mean the primary casters have to sit that fight out... Though if it's more like old school, lots of magic effects might still work on them (conjugations, illusions, etc)

On the other hand: I love the examples of exciting table moments Hemlock's idea could generate. And it keeps casters a bit more directly functional in fights against magic "immune" foes. But it's complex, man. Maybe a little too complex, with several possible new interaction vectors to keep in mind.

Not sure which I might use. Could depend on the feel I'm going for.

Inclination is to give some of Hemlock's immunity powers to some specific monsters I designate just because they seem terrifying and awesome, and to use Zardnaar's version more generally if I want to a harsher, more old school campaign.

 

[Trickster Spirit]

Overall, I fear most suggestions are way too complex to fit the 5e "idiom".

Here's something simpler:

The Mind Flayer can cast Counterspell as a third level spell as a reaction each round.

This way, you have a ready-made 5e mechanism working for you.

Moreover, it comes with a built-in "magic resistance roll" already!

(This roll is rounded up to 100% resistance for incoming spells of third level or lower, rounded down to 0% for any spells non countered, and a number somewhere probably right above 50% for fourth level spells slowly sinking to 20-30% for level 9 spells.

But if you add the advantage on any saves the Flayer already got, the resulting resistance would be higher in practice.

If you want to talk about practical effects, yes, this would mean the party would mainly use sword and sticks on Mind Flayers, which was the entire point after all, right?)

It might not be exactly the AD&D rule, but it is very simple and very 5e!

This would be my preference - that way a Mind Flayer can still shrug off a Fireball or bolt of lightning seemingly unharmed, but still allow for groups to overwhelm it with sheer concentrated spellfire.

 

[CapnZapp]

Thank you

 

[CapnZapp]

Correct and not, simultaneously, again.

Bonus points for style!