What CR should a "Spell Shield" (like with Rakshasa) start?

[Man_Over_Game]

I like the idea of low level spell slot damage spells still being relevant, but this is not always true when cantrip damage scales with level.

To incentivize players to utilize the occasional damaging low level spell rather than relying on cantrips, I wanted to implement a type of passive defensive ability, "Spell Shield", that nullifies any spell below a certain level.

Rakshasa have this as an ability that prevents any spells from level 5 or under, I just want to duplicate it on to lower level creatures.

For each level, what seems the most reasonable for each spell slot level?

I'd probably say a level 0 Spell Shield (immune to cantrips) seems reasonable starting at CR 3, but when should it be capped? Should there be a creature who resists level 8 spells? I want to hear what you guys have to suggest.

[PhoenixPhyre]

I like the idea of low level spell slot damage spells still being relevant, but this is not always true when cantrip damage scales with level.

To incentivize players to utilize the occasional damaging low level spell rather than relying on cantrips, I wanted to implement a type of passive defensive ability, "Spell Shield", that nullifies any spell below a certain level.

Rakshasa have this as an ability that prevents any spells from level 5 or under, I just want to duplicate it on to lower level creatures.

For each level, what seems the most reasonable for each spell slot level?

I'd probably say a level 0 Spell Shield (immune to cantrips) seems reasonable starting at CR 3, but when should it be capped? Should there be a creature who resists level 8 spells? I want to hear what you guys have to suggest.

I would be seriously annoyed as a spell-caster if this was a regular thing. Cantrips are the bread and butter of casters--no one has slots to waste anymore. And having to waste my "big guns" on something just to have an effect is obnoxious if it's not just a one-off puzzle monster (like the Rakshasa are).

[Snowbluff]

Well considering whole classes will never be able to do anything against a magic immune enemy, I think it should be used sparingly. You need to at least have a few spell levels available for your players to use, so the CR has a be a few levels against of what level someone gets those spells.

I don't think anything should be immune to cantrips. It's like making/using enemies immune to weapon attacks. Just kinda cheap.

[Man_Over_Game]

I would be seriously annoyed as a spell-caster if this was a regular thing. Cantrips are the bread and butter of casters--no one has slots to waste anymore. And having to waste my "big guns" on something just to have an effect is obnoxious if it's not just a one-off puzzle monster (like the Rakshasa are).

I mean, would you really be that mad if there was a CR 5 creature that just ignored cantrips? In my perspective, if I considered it a real threat, I'd already be loading my highest level spells into it in the first place. CR 2 did seem a little light, thinking about it.

[PhoenixPhyre]

I mean, would you really be that mad if there was a CR 5 creature that just ignored cantrips? In my perspective, if I considered it a real threat, I'd already be loading my highest level spells into it in the first place.

If I knew that was the only fight in the day? Sure. Otherwise, I'd let the weapon-types handle it and buff them instead. And dance.

Edit: and you wouldn't know it's immune to all cantrips unless the DM says so--you'd probably waste a couple rounds trying different damage types...which totally sucks.

[Man_Over_Game]

Well considering whole classes will never be able to do anything against a magic immune enemy, I think it should be used sparingly. You need to at least have a few spell levels available for your players to use, so the CR has a be a few levels against of what level someone gets those spells.

I don't think anything should be immune to cantrips. It's like making/using enemies immune to weapon attacks. Just kinda cheap.

Sure, but there are a plethora of creatures that are resistant/immune to nonmagical damage, or bludgeoning/slashing/piercing damage. People have always been griping about how the Martial is always inferior to the Wizard Master Race, I feel like this is a small step in creating a balanced solution.

A Fighter cannot "choose" to make his weapon magical, but a Wizard can always choose to spend a spell slot.

[PhoenixPhyre]

Sure, but there are a plethora of creatures that are resistant/immune to nonmagical damage, or bludgeoning/slashing/piercing damage. People have always been griping about how the Martial is always inferior to the Wizard Master Race, I feel like this is a small step in creating a balanced solution.

A Fighter cannot "choose" to make his weapon magical, but a Wizard can always choose to spend a spell slot.

Very few that are flat out immune, and most of those are handled by silver. Resistant is fine, immune is not.

And people griping are just griping. They're stuck in the 3e era.

[Unoriginal]

That kind of Spell Shield is a force multiplier for the monster, or rather a force divider for their opponents, aka the party. So it's rather difficult to answer your question, since it varies a lot depending on what the monster is capable of aside from being impossible to affect for X percent of the party casters' arsenal.

I don't think there should be creatures immune to spells above the 7th level. It'd make them superior to Tiamat's divine spell shield, if they had it, and I don't think it's a good idea to add that to the game.


I would be seriously annoyed as a spell-caster if this was a regular thing. Cantrips are the bread and butter of casters--no one has slots to waste anymore. And having to waste my "big guns" on something just to have an effect is obnoxious if it's not just a one-off puzzle monster (like the Rakshasa are).

I wouldn't call cantrips the bread-and-butter of casters, aside from the Warlock which is designed for that.

Cantrips aren't the main power of the casters, nor their signature move. It's what they fall back on when using spell slots is impossible or ill-advised (because they want to keep their slots for bigger problems, for example).

[PhoenixPhyre]

That kind of Spell Shield is a force multiplier for the monster, or rather a force divider for their opponents, aka the party. So it's rather difficult to answer your question, since it varies a lot depending on what the monster is capable of aside from being impossible to affect for X percent of the party casters' arsenal.

I don't think there should be creatures immune to spells above the 7th level. It'd make them superior to Tiamat's divine spell shield, if they had it, and I don't think it's a good idea to add that to the game.



I wouldn't call cantrips the bread-and-butter of casters, aside from the Warlock which is designed for that.

Cantrips aren't the main power of the casters, nor their signature move. It's what they fall back on when using spell slots is impossible or ill-advised (because they want to keep their slots for bigger problems, for example).

At lower levels, you have ~ 1 slot per encounter, mostly lower level. Yes, at higher levels you have less to conserve. At level 3? You just don't have enough of them.

Edit: and it's not like you know what it's immune to. So you waste a low level, and then a higher level...so you waste 2-3 turns with no effect and wasted resources. Yay? Immune to weapon damage is pretty clear from the get-go.

[Man_Over_Game]

Hmm...Gives me an idea, thinking about it.

Spell Shield can have two different forms, Physical or Magical. When receiving a physical attack, the creature can spend their reaction to turn the Spell Shield Physical, granting 2x its value as AC. When receiving a spell, the creature can turn the Spell Shield Magical, stopping spells who's spell level is less than the Spell Shield value, and gaining its value as a bonus to save against spells.

Could be interesting, creating a boss that has an adaptive shield that you have to plan around. Not part of the main discussion, and I don't want it to be, just was a cool idea.

[Rukelnikov]

Maybe have it cost something to the monster so the caster doesn't feel his action had 0 effect.

Like for instance, a Nishruu could have "Magic fagocitation: When targeted by a spell or forced to make a saving throw by one, a Nishruu can spend its reaction to negate the effect"

You can limit this to spells of X level as you originally said, or you can make less reliable by having it be kind of a "counterspell"

Karsite resistance: "When targeted by a spell or forced to make a saving throw by one, the Karsite can spend his reaction to negate any effect of 3rd lvl or lower on itself only (a fireball would still damage any other creature in the area), for higher level spells it must roll Cha + prof against a DC of 10 + Spell level"

[MaxWilson]

I mean, would you really be that mad if there was a CR 5 creature that just ignored cantrips? In my perspective, if I considered it a real threat, I'd already be loading my highest level spells into it in the first place. CR 2 did seem a little light, thinking about it.

Eh, depends how frequent it was. If it was a common thing in a given campaign I'd adjust my playstyle accordingly (maybe play fighters more often), but if it's just a one-off adventure with those guys I'd either just let the fighters deal with it or I'd summon up a Fire Elemental just like I would for a Rakshasa.

That assumes I'm a wizard of course. If I were a warlock I might be significantly more distressed. :-)


Maybe have it cost something to the monster so the caster doesn't feel his action had 0 effect.

Like for instance, a Nishruu could have "Magic fagocitation: When targeted by a spell or forced to make a saving throw by one, a Nishruu can spend its reaction to negate the effect"

You can limit this to spells of X level as you originally said, or you can make less reliable by having it be kind of a "counterspell"

Karsite resistance: "When targeted by a spell or forced to make a saving throw by one, the Karsite can spend his reaction to negate any effect of 3rd lvl or lower on itself only (a fireball would still damage any other creature in the area), for higher level spells it must roll Cha + prof against a DC of 10 + Spell level"

That's how I run Legendary Resistance and Magic Resistance actually: instead of just a passive ability that gives advantage on saves or makes you auto-pass saves, it costs a reaction and the monster gets to make an ability check to negate the spell.

Variant rule: Magic Resistance
[This rule replaces both Monstrous Manual Magic Resistance and Legendary Resistance. Creatures with one or the other should be assigned a Magic Resistance ability and score.]

Some extremely powerful creatures strongly resist and disrupt the effects of magical energy. These creatures live and breath arcane energy, and by an act of will they can cause magic to recoil from them like water droplets skittering off a hot griddle.

A creature with Magic Resistance can apply that resistance whenever it is affected by a magical effect by expending its reaction. If there is a saving throw or attack roll involved, it can wait until the result is known before deciding to use Magic Resistance. When Magic Resistance is used, the creature makes an ability check against the DC of the magical effect (similar to Counterspell) and if the check succeeds, the magical effect is negated. Unlike Counterspell, the check need not occur at the instant of spellcasting. A Magic Resistant creature could, for example, attempt to walk through a Wall of Force, and at the instant where the Wall of Force prevents its movement, expend its reaction to dispel the Wall of Force. A Magic Resistant Creature could similarly choose at any time to resist the effects of a Maze spell holding it captive or a Planar Binding spell compelling its obedience.

Example: Esmerelda the Enchantress casts Hold Monster VII on a Balor with DC 18. It rolls an 11 on its saving throw and fails. But before the magic takes hold, the Balor resists the magic! A Balor has +12 to Charisma (Magic Resistance), and Esmerelda cast the spell at 7th level, so the Balor has to make a Charisma (Magic Resistance) roll of DC 17 to avoid being paralyzed. It rolls a 21 and shatters the spell! The spell ends, freeing the Balor and any other creatures targeted by the spell.

Note: because a reaction is required, Magic Resistance cannot be used by creatures who are surprised or incapacitated.

Note 2: because Magic Resistance is an ability check, things which affect ability checks including Hex and Cutting Words do affect Magic Resistance rolls. This is by deliberate mechanical analogy to Counterspell.

Note 3: whether things like a monk's Stunning Strike can be resisted with Magic Resistance depends on how your DM interprets whether they are magical or not. Magic Resistance is not limited strictly to spells but does apply only to things that are fundamentally magic. If the DM rules that magic resistance applies to Stunning Strike, he will also tell you what level spell each strike is equivalent to for purposes of Magic Resistance. It might be appropriate to set the level equal to the monk's proficiency bonus.

Variant: some DMs might want the players to do the rolling instead of the monsters. A mathematically-equivalent formulation to the above is: monster spends its reaction to set a DC equal to 12 + Charisma (Magic Resistance). The player then has to roll to beat that score with a bonus equal to the level of the spell. In the case of Esmerelda, she can roll at +7 to beat the Balor's DC 24. Just as before, there are 4 chances in 20 that the Balor is affected by the spell.

Note: If a creature attempts to use its magic resistance against a given spell and fails, that represents being unable to resist this casting of that spell unless its magic resistance improves--any retries will result in failure. E.g. if you've got a demon bound with Planar Binding, the demon gets only one chance to resist that Planar Binding. (But a crafty demon may not test the Planar Binding right away so be on your guard.)

If magic resistance fails due to temporary circumstances like Hex or Cutting Words, that represents a temporary failure which can be overcome if the creature retries without the hindance. In this rare circumstance, the DM may record the original d20 roll prior to the temporary modifiers, and re-use it on the subsequent attempts. (Or the DM may choose another equivalent method with the same probability curve.) Ditto for temporary improvements: a demon which rolls a 7 (failure) on its MR check against Planar Binding, but then receives Enhance Ability (Charisma) and tests the spell again, would roll one new die, compare it to the previous 7, and take the higher result.


Link: http://bluishcertainty.blogspot.com/2016/03/5e-magic-resistance-variant-rule.html

[Chronos]

If it weren't for warlocks, I'd say go ahead... but most warlocks are nothing without Eldritch Blast, and don't really have much they can do instead. And even if they do have spells known that are relevant and useful against the monster, what do they do on Round 4 of the fight? They probably don't even have a weapon that they can try to be really bad at using.

Making one character in a party completely useless is never good design.

[MaxWilson]

If it weren't for warlocks, I'd say go ahead... but most warlocks are nothing without Eldritch Blast, and don't really have much they can do instead. And even if they do have spells known that are relevant and useful against the monster, what do they do on Round 4 of the fight? They probably don't even have a weapon that they can try to be really bad at using.

Making one character in a party completely useless is never good design.

I disagree. Making a PC useless for an adventure or a campaign is a problem, but it's not a problem if a given challenge is handled by one or more PCs instead of the full group. A locked door for example that the thief picks isn't bad even if the cleric feels "useless" against it. Just don't let it drag on too long.

If a player can't handle five minutes of not being in the spotlight, something is wrong.

Besides, even without spells, a warlock could still Help, grapple/shove, fight other monsters, scatter ball bearings, draw fire, etc. That's not useless, it's teamwork.

[Man_Over_Game]

I mean, lets not forget that the warlock is more likely to have high level spell slots prepared than any other caster.

[Zhorn]

I would be seriously annoyed as a spell-caster if this was a regular thing. Cantrips are the bread and butter of casters--no one has slots to waste anymore. And having to waste my "big guns" on something just to have an effect is obnoxious if it's not just a one-off puzzle monster (like the Rakshasa are).
Agreed, this would be frustrating more than fun. Alternative idea:
Give the enemies non-recharging magic items that as a reaction negates Ndn type damage.
If that players know what it is the can choose to:

Burn through its charges
Attempt to remove the item so their attacks are not nullified
Change to a different damage type, or (as you have as a goal) a higher damaging spell

And if the players get a hold of the item, the limited usage shouldn't cause much of a balance upset for long.
Plus, number or charges and size of the damage reduction can be scaled for a range of CRs, and adjusted on the fly when it's not hitting the intended mark.

[Helldin87]

I think the better solution and more elegant one is to use resistances. Fire/Frost resistance take out most of your damaging cantrips right away. OR at least render them super weak. This is also on par with weapon resistances so your martials can take a moment to shine.

Additionally characters that acquire knowledge of their foes and take a variety of damage schools for just such an occasion are rewarded for their insight and preparedness. PCs that think "firebolt is good for everything" are in for a rude surprise.

I would not arbitrarily say that "spell level X and below do nothing" For one thing I would be super pissed as a PC if I used a magic missile lvl 1 and was told that due to this arbitrary and passive rule it did nothing.

Maybe allowing your spellcasters to use counterspell more? This at least uses their slots and reaction, rendering them unable to opportunity attack or cast shield. I doubt many of your encounters have a caster enemy that runs out of spell slots naturally. (mine seem to die before they get too many casts off personally)

[MaxWilson]

I mean, lets not forget that the warlock is more likely to have high level spell slots prepared than any other caster.

But only up to 5th level spell slots. :)

[Knaight]

I like the idea, though I'd tend towards resistance instead of immunity. You'd need a good description in the setting fiction, both in terms of why it works and in terms of describing what actually happens when a low powered spell hits that clearly indicates that it isn't doing much.

Personally, I tend to lean towards thinking of this in terms of conductivity and resistance*, in a very general sense. Weapons fit with this, where bludgeoning conductivity is to some extent the way shock waves from impact affect materials and slashing/piercing conductivity is to some extent the way small sharp objects move through materials. Electrical and thermal conductivity fit here as normal, and magic operating in a similar way has a long tradition in fantasy, and even D&D.

As a sample, take a lead golem. Bludgeoning resistance makes sense, as soft metals really don't propagate shock waves well. Slashing conductivity also makes sense, as steel with go through lead just fine, though outright vulnerability isn't necessary given that it's no weaker than flesh. Electrical and thermal conductivity are basically the same as ever, and magic? Lead having staggeringly low magical conductivity is traditional, it's up there with cold iron in terms of traditionally blocking magic. In D&D specifically it's arguably better at it, between specifically being called out in scrying and there not being magical lead weapons lying around.

Similarly particularly magical materials are all over the place in fantasy. Jade is often particularly magical. Mercury is often particularly magical. Willow, rowan, and ebony are often particularly magical. Dragons and fey are generally just more magical than people. D&D isn't particularly consistent in how this is applied, so there's a lot of leeway there for implementation, ith spell shielding basically being analogous to spell resistance in previous editions.

*I wouldn't use these terms unless I was going full science/industrial fantasy due to genre connotations, but the intuitive concepts behind them work just fine.

[Kane0]

Cr 3 for cantrips sounds reasonable, plus another 2 or so Cr for each spell level above that

[SkipSandwich]

The rakshasa is CR 13 and immune to 5th level spells and below.

A 13th level fullcaster has 1 6th and 1 7th level spellslot. If we carry that logic down (two spell levels higher than the immunity) then we get the following cut-offs.

CR 11 for 4th tier immunity
CR 9 for 3rd tier immunity
CR 7 for 2nd tier immunity
CR 5 for 1st tier immunity
CR 3 for Cantrip immunity

[Man_Over_Game]

Cr 3 for cantrips sounds reasonable, plus another 2 or so Cr for each spell level above that


The rakshasa is CR 13 and immune to 5th level spells and below.

A 13th level fullcaster has 1 6th and 1 7th level spellslot. If we carry that logic down (two spell levels higher than the immunity) then we get the following cut-offs.

CR 11 for 4th tier immunity
CR 9 for 3rd tier immunity
CR 7 for 2nd tier immunity
CR 5 for 1st tier immunity
CR 3 for Cantrip immunity

This sounds fairly reasonable. I'm not too terribly worried about casters being unable to cast cantrips. At the most extreme case in this example (CR 3), a character of equal level has 6 leveled spell slots available, where against a Rakshasa, a character of equal level has 2 usable slots. Seems fine.

These creatures would likely have a lot of rumors circling them in mage culture, so it seems very reasonable that the players would know about them beforehand.

[PhoenixPhyre]

These creatures would likely have a lot of rumors circling them in mage culture, so it seems very reasonable that the players would know about them beforehand.

The characters might know, but do the players? I guess that goes to how much information do you give the players for free. Because they won't know that they need to ask the question if such a thing is new to them as players.

[Man_Over_Game]

The characters might know, but do the players? I guess that goes to how much information do you give the players for free. Because they won't know that they need to ask the question if such a thing is new to them as players.

I'm not the kind of DM that introduces a weird thing to startle or confuse my players just to see them fail; I give them plenty of warning before they run into an Intellect Devourer, but I'll have no sympathy if you die anyway.


I consider clues to be my version of the "terms and conditions" of monsters, and skimming over them counts as enough consent for me.

[Snowbluff]

Sure, but there are a plethora of creatures that are resistant/immune to nonmagical damage, or bludgeoning/slashing/piercing damage. People have always been griping about how the Martial is always inferior to the Wizard Master Race, I feel like this is a small step in creating a balanced solution.

A Fighter cannot "choose" to make his weapon magical, but a Wizard can always choose to spend a spell slot.

I'd say those monsters are dumb and generally a pain in the ass. I said so in my post. You're "but" and everything after it is dead air.

Also fighters are dumb. They deserve to be bad for not having options in their build, but that's just me.

However, finding balance is 1) stupid because people don't understand what we mean when we tell them Wizard is better and 2) will encourage the actual strategies that actually upset game balance, like spamming simulacrums and the like. Trying to retro-balance the classes by making monsters that just "lol nope" huge categories of abilities is plainly stupid because it means the players are doing less and making fewer decisions. Furthermore, half and quarter casters will be unduly punished, lol noping huge parts of their abilities.

After that, it is the Wizards job to spend spell slots more than anything; if they're not spending those slots they aren't doing a whole lot. So what, are wizards (and not just wizards but clerics, sorcerers, bards and druids) are supposed to play mind reader against Schrodinger's monsters, guessing that later in the day they won't run into a monster that will require them to use that higher level slot they need to use right now?

[Man_Over_Game]

I'd say those monsters are dumb and generally a pain in the ass. I said so in my post. You're "but" and everything after it is dead air.

Also fighters are dumb. They deserve to be bad for not having options in their build, but that's just me.

However, finding balance is 1) stupid because people don't understand what we mean when we tell them Wizard is better and 2) will encourage the actual strategies that actually upset game balance, like spamming simulacrums and the like. Trying to retro-balance the classes by making monsters that just "lol nope" huge categories of abilities is plainly stupid because it means the players are doing less and making fewer decisions. Furthermore, half and quarter casters will be unduly punished, lol noping huge parts of their abilities.

After that, it is the Wizards job to spend spell slots more than anything; if they're not spending those slots they aren't doing a whole lot. So what, are wizards (and not just wizards but clerics, sorcerers, bards and druids) are supposed to play mind reader against Schrodinger's monsters, guessing that later in the day they won't run into a monster that will require them to use that higher level slot they need to use right now?

Using Rakshasa as an example, a caster of equal level has two spell slots to use across the entire day that would be effective against the Rakshasa. Now, a CR 3 creature with the ability to block cantrips is susceptible to 6 slots. A CR 5 creature, blocking level 1 spells, is susceptible to 5 slots. A CR 7, blocking level 2 spells, is susceptible to 4 slots.

In fact, the most debilitating example of the "spell shield" concept is the Rakshasa, a creature that actually exists, at a CR where a few multiclass levels could determine the difference of being able to cast any spell worthwhile or not. The worst case scenario is already real, and I'm suggesting a few concepts that are just easier to deal with.

----------

We have flying enemies when we have barbarians, enemies who are resistant to nonmagical damage when we have fighters, entire portions of creatures that are immune to fear with a Paladin who makes fear his entire subclass feature, a Shadow Sorcerer who's main feature is blinding everyone in a game where enemies have blindsense and your friends don't.

Sometimes, the game just sucks for you in particular, and sometimes you just gotta deal with it. I can't think of many examples of mages having to worry about particular creatures the same way a Conquest Paladin has to worry about the undead/aberrations/fiends.

[Kane0]

Dont forget poison and all the things it doesnt work on.

[Mad Max]

I wouldn't use it as a universal ability for enemies, but for a specific enemy (or enemy type, e.g. the villains in a single adventure) as a gimmick, it's neat. Whether or not it's worth doing, based on the risk of it potentially upsetting game balance, depends on your reason for instituting the rule. I've never personally felt that spell-casters in 5e use too many cantrips and not enough low level spells, but maybe your group is different, and if it works for your campaign than of course you should do it!

If you plan to do it though, I'd be worried about the non-full spell/multiclass casters. While they don't rely on magic as much as the full-casters do, their spells are almost certainly going to be useless against even a low-level magic shield, simply because they don't have high enough level spells.

[Snowbluff]

We have flying enemies when we have barbarians, enemies who are resistant to nonmagical damage when we have fighters, entire portions of creatures that are immune to fear with a Paladin who makes fear his entire subclass feature, a Shadow Sorcerer who's main feature is blinding everyone in a game where enemies have blindsense and your friends don't.

Sometimes, the game just sucks for you in particular, and sometimes you just gotta deal with it. I can't think of many examples of mages having to worry about particular creatures the same way a Conquest Paladin has to worry about the undead/aberrations/fiends.

Compare how niche these examples actually are compared to spells.

Conquest paladin's fear ability is twice per short rest. A conquest paladin will spend most of their time attacking, smiting, and casting spells. Even if your fear option isn't an option, you have everything a paladin normally does, AND can still spend their Channel Divinity resource on Guided Strike instead.

A shadow sorcerer has spell. Their main feature is the doggo, if you ask me, but most of their time will be spent casting spells instead. Furthermore, your spellpoint cost darkness ability competes with your normal metamagic features.

You mention enemies who are resistant to nonmagical damage, again, when I pointed out it was a bad point already. Furthermore, magic weapons aren't actually hard to come by. You can start with a common magical weapon in your backstory with Xanathar's, and just about everything after 5 drops a magic weapon.

Barbarians still can whip weapons at people and use bows. It's not optimal, but they're still definitely doing something. Actually, the only real problem they'd have is getting resistance from rage.

So, no, I will tell you I won't just "deal with" not being able to play a session because the DM is in the mood to mess with the casters in the team in particular.

[Teaguethebean]

Also if we think like this using the CR 3 who is immune to cantrips let's use our friend Richard he is a lv 3 storm sorcerer he doesn't like wading into melee as his ac is subpar and he has low strength so he stands back and casts spells. If we use the DMG 6 encounters per day he has as a lv 3 caster 6 spells (add 1 or 2 if he doesn't use metamagics). Should he only do one attack per encounter because that sounds kinda trash.

[Kane0]

Compare how niche these examples actually are compared to spells.
Conquest paladin's fear ability is twice per short rest. A conquest paladin will spend most of their time attacking, smiting, and casting spells. Even if your fear option isn't an option, you have everything a paladin normally does, AND can still spend their Channel Divinity resource on Guided Strike instead.

Casters can also use spells on themselves and allies instead of the enemy in the same fashion.



Barbarians still can whip weapons at people and use bows. It's not optimal, but they're still definitely doing something. Actually, the only real problem they'd have is getting resistance from rage.

The same logic could be applied to casters that can't do their default thing.

I think you may be overstating the problem. You aren't barred from play, you simply cannot use lower level spells directly against that creature. You aren't losing access to any of your other actions, gear or spells that don't affect that creature.


Also if we think like this using the CR 3 who is immune to cantrips let's use our friend Richard he is a lv 3 storm sorcerer he doesn't like wading into melee as his ac is subpar and he has low strength so he stands back and casts spells. If we use the DMG 6 encounters per day he has as a lv 3 caster 6 spells (add 1 or 2 if he doesn't use metamagics). Should he only do one attack per encounter because that sounds kinda trash.

Are we fighting spell immune enemies six times a day?

[Sigreid]

To me, this whole idea hinges on how often your talking about. If it's most encounters, that's a bad idea and your casters are going to be upset. If it's an occasional thing done to shut down their normal tactics and see what they come up with as an answer, then it's fine. This is just like the group with a fighter that has no magic weapons shouldn't be facing weapon resistant/immune monsters very often.

[Snowbluff]

Casters can also use spells on themselves and allies instead of the enemy in the same fashion.
To limited effect, assuming they packed those spells in the first place.


The same logic could be applied to casters that can't do their default thing.

I think you may be overstating the problem. You aren't barred from play, you simply cannot use lower level spells directly against that creature. You aren't losing access to any of your other actions, gear or spells that don't affect that creature.


No it can't.

The back up when spells aren't the way to go are cantrips, which won't work at all in these situations (RIP warlocks). The other option is a cross bow, which as you get up in level and with the limited ability increases, is looking at 1d10+3 damage at most.

Barbarians have extra attack. They can make 2 attacks using strength with thrown, which will continue rage. Since Strength is their main stat, all they're losing is the rage damage bonus and the die size difference between their thrown weapon and their main one.

That is to say, the difference isn't remotely comparable and I misspoke when I said that continuing rage would be a problem. Furthermore, if you think this is a problem, then wouldn't extending the failure of Barbarian's class design to other classes be a huge mistake?

[Sulicius]

To me, this whole idea hinges on how often your talking about. If it's most encounters, that's a bad idea and your casters are going to be upset. If it's an occasional thing done to shut down their normal tactics and see what they come up with as an answer, then it's fine. This is just like the group with a fighter that has no magic weapons shouldn't be facing weapon resistant/immune monsters very often.

This is the best answer, for sure. Unlike the rest here, I actually have made monsters that have magic immunity and used them against my players. They are Fleshhounds of Khorne and their whole thing is that they are incredibly magic resistant because of the magical collars they wear. I made them immune to spells level 2 and lower as CR5 against a group of level 8. They're pretty much Dire Wolves boosted up with some fiendish features.

Now first off: I made sure that there was only one of them, with 3 other fiends who were NOT immune to these spells. Once my players learned about it, they looked at their spells in a different way. The melee guys just kept on stomping without a care in the world.
Second off: My party has only two full spellcasters, a druid and a warlock. Yeah, the Warlock did struggle once he figured out he couldn't use his eldritch blast, and started looking whatever ranged weapon he started off with. The Druid usually polymorphs into a giant ape, so I wasn't worried.
And third, these guys are built around this immunity: they don't have boatloads of health.

https://i.imgur.com/vPdvHgx.png
Nothing too crazy, just another puzzle the players would need to solve. Of course, one of the PC's stole the collar and is now cursed, so he'll soon have this guy on his tail:
https://i.imgur.com/ggru4EN.png

As someone who homebrews tons of monsters, I'd say try it. Be honest with your players that you're testing homebrewing with crazy mechanics. They'll probably understand. If you use it and you're wrecking your party, you could make your monster lose the immunity once it's at half hit points.

[Pez5150]

Instead of giving them spell immunity to cantrips, why not just give the monster an ability that can use it's reaction to nullify cantrips a.k.a a weak counterspell or cast the shield spell? Once it uses the shield ability it can't use weak counterspell and vice versa. This way it's not permanent and you aren't singling out an entire class. Put them in a group and give the monsters low health. Then the whole key to the battle would be for the players to intentionally force the monsters to pop their ability so someone else could pop their head off. Generally high CR monsters like liches have magic resistance and rakshasa had limited immunity because it's that good to have. As far as CR if you give the creature immunity to cantrips I'd probably add a level for the CR.

If you take a mundane CR 1 creature and give it immunity to Cantrips I'd make it a CR 2 or 3 since you've upped it's defence. A CR 1 monster may have a CR 0 defense and a CR 2 attack which case averages to CR 1. If you take a monster with CR 0 attack and CR 2 defense and give it the immunity to cantrips , I'd add 1 or 2 levels to defense and call it CR 2. Any case some monster abilities may have unexpected synergy with a monster. Imagine the goblin having cantrip immunity when it can use it's bonus action to hide. This means you'll need a lot of playtesting.

Honestly it depends a lot on what creature you want to use, do you know what base creature you're trying to use?