Detect Magic Invalidates the School of Illusion

[JonBeowulf]

This thread was close, but didn't quite get there...
https://forums.giantitp.com/showthread.php?626508-Detect-Magic-Vs-Illusions-(and-casters-in-general)&highlight=detect+magic

I can find nothing RAW that contradicts the title. It seems a single 1st level spell totally ruins the entire School of Illusion.


For the duration you sense the presence of magic within 30 feet of you. If you sense magic in this way, you can use your action to see a faint aura around any visible creature or object in the area that bears magic, and you learn its school of magic, if any.

You sense the magic is there (so Invisibility and similar are borked) and if you can see it, you know the school of magic (so all visible illusions are borked).

This feels broken and cannot be right... someone please tell me how I'm reading this wrong.

[Abracadangit]

"For the duration you sense the presence of magic within 30 feet of you. If you sense magic in this way, you can use your action to see a faint aura around any visible creature or object in the area that bears magic, and you learn its school of magic, if any."

So it sounds like the creature/object has to be visible for you to detect its aura in the first place. I bet they even included that "visible" in there specifically so it wouldn't counter Invisibility, and so you couldn't use it like Magic X-Ray Vision to find magic items through dungeon walls.

By my reckoning, Invisibility is still good to go.

Edit: caveat, it does sound like you can SENSE that something magicky is within 30 ft of you, but that would be as much utility as you get.

[sayaijin]

I will say that knowing something magical is happening around you doesn't tell you it's an illusion. Also, even if they know there's an illusion, they won't know exactly what is illusive.

Example:

Players come to a rope bridge. It has a faint glow (I've given them reason to suspect magic)
Paranoid PC (PPC): I cast detect magic!
DM: You sense illusion magic

Now, the players will likely try to see if the bridge is real and if it can support them. Well they were going to do that anyways. Besides, the arch mage who conjured the illusive bridge is using Illusory Reality to make it real until they get halfway across. Then they learn to respect illusion more and depend on detect magic less.

[meandean]

This thread was close, but didn't quite get there...
https://forums.giantitp.com/showthread.php?626508-Detect-Magic-Vs-Illusions-(and-casters-in-general)&highlight=detect+magic

I can find nothing RAW that contradicts the title. It seems a single 1st level spell totally ruins the entire School of Illusion.



You sense the magic is there (so Invisibility and similar are borked) and if you can see it, you know the school of magic (so all visible illusions are borked).

This feels broken and cannot be right... someone please tell me how I'm reading this wrong.Okay, but either:

A) You're using both your concentration and your actions to pin down the exact location of the magic. You can do that fine outside of combat. But once a fight starts, it's gonna be tough for you to continue to function as radar and not be able to do anything else.

or, B) You just know that there's magic somewhere within 30' of you. You don't know that it's illusion magic, much less that it's invisibility specifically. Even if you did figure out through further evidence that something is invisible, you might have to play a lengthy game of Battleship to determine exactly where within that (relatively large) space it is. And again, you can't concentrate on anything else while doing this.

[JonBeowulf]

Perhaps it was deliberate. The designers knew that PC illusion spells were at the mercy of DMs so they gave the players a way to counter DM illusion spells. :smallwink:

If I have DM up, and detect magic within 30' of me, I can use an action (a useless statement outside of combat) to see the aura around all illusions. Nice try, BBEG, but I see through your lies.

[Segev]

Point of order: nothing in Illusory Reality suggests that you can un-real it at will, rather than having to wait for the 1 minute duration on the effect to expire. Not even ending the illusion early necessarily does it; there's a lot of DM call here. Now, the DM is controlling the archmage, but he should be aware of the precedent he's setting with the ruling.

[Anymage]

Concentration for ten minutes. So it precludes other concentration effects. The tradeoffs of a spell slot vs. ten minute ritual cast time also ask what you're willing to give up, but suffice to say keeping it up 24/7 is rather impractical.

While it's up you can just say "ayup, there's magic here". More detailed information - which notably requires seeing the target, so no bypassing invisibility - takes up your action. A not insignificant cost in combat.

And finally, any illusionist worth their salt will also know nystul's magic aura. Which will throw off the detections for other magic effects, allowing a magical object to seem nonmagical or vice versa. So yes. Pure illusion based traps in an area where the PCs have reason to expect magic traps and consequently have Detect Magic up are going to suffer. That's just a small sliver of what a competent illusionist has up his sleeve, so I don't see it as being so crippling.

[Man_Over_Game]

This thread was close, but didn't quite get there...
https://forums.giantitp.com/showthread.php?626508-Detect-Magic-Vs-Illusions-(and-casters-in-general)&highlight=detect+magic

I can find nothing RAW that contradicts the title. It seems a single 1st level spell totally ruins the entire School of Illusion.



You sense the magic is there (so Invisibility and similar are borked) and if you can see it, you know the school of magic (so all visible illusions are borked).

This feels broken and cannot be right... someone please tell me how I'm reading this wrong.

It is worth noting that this is copy-pasted for most standard illusion spells:

"If a creature uses its action to examine the sound or image, the creature can determine that it is an Illusion with a successful Intelligence (Investigation) check against your spell save DC. If a creature discerns the Illusion for what it is, the Illusion becomes faint to the creature."

Now, the lead developer for 5e is pretty lenient on what an "action to examine the sound or image" is. For instance, taking the Search Action upon entering the room, making an Insight check against you while you have Disguise Self, or a similar example is something he (and I) would allow to be used. Otherwise, Illusions are undetected until they're obviously interfered with.

Compare this with Detect Magic's "If you sense magic in this way, you can use your action to see a faint aura around any visible creature or object in the area that bears magic, and you learn its school of magic, if any." Detect Magic already costs an Action to cast. So basically, Detect Magic costs you a spell, possibly a spell slot, and an additional action so that...you don't have to roll a successful Investigation Check?

And I do get that this can also include using Detect Magic against some high level spells, but Magic Aura was literally designed for this. The thing is, people are accustomed to technology. If you walk past a guard that's using Detect Magic to weed out any infiltrators, they are not going to be looking for someone who foiled that simple, level 1 system. We barely do "double checks" in the real world (although I admit a lot of this is going to depend on your DM).

[J-H]

An illusion is neither a creature, nor an object. It is a non-solid figment*. As such, it does not register with Detect Magic. A non-invisible object affected by an illusion (such as changing the color of a self-destruct button from red to blue) would register.

*Solid illusions created by high-level illusionists may break this semantic analysis. I'm not sure.

[PhoenixPhyre]

And technically, the "presence of magic" includes
* Any spells you or your party has active
* (more controversially) any magic items you or your party has
* your ally's (or your own) familiar
* Etc.

That "ping" is binary, it's not radar. You know "there is magic nearby". Which, in the main, will be drowned out by the "sure, you're dripping with magic items" returns. Not where it is--it doesn't help localize it unless you do some careful triangulation in a noise-free environment. And free-standing illusory creations are neither creatures nor objects, so unless it's something like disguise self (or another spell cast on a creature or object), you can't use the second clause at all.

[Willie the Duck]

Regardless, I think Man_Over_Game has it -- illusions were already relatively easy to foil, using less effort, but taking precious combat actions either way. In non-combat situations, yeah it stinks that they are so easily foilable, but their duration limits and such made most of them useful for combat or 'talk your way past the guards in corridor B'-type scenarios anyways. Fear that certain spells might run away with the game certainly seemed to constrain both illusions and enchantments in this edition.

[MaxWilson]

This thread was close, but didn't quite get there...
https://forums.giantitp.com/showthread.php?626508-Detect-Magic-Vs-Illusions-(and-casters-in-general)&highlight=detect+magic

I can find nothing RAW that contradicts the title. It seems a single 1st level spell totally ruins the entire School of Illusion.

You sense the magic is there (so Invisibility and similar are borked) and if you can see it, you know the school of magic (so all visible illusions are borked).

This feels broken and cannot be right... someone please tell me how I'm reading this wrong.

Detect Magic is useful, as it should be, but it doesn't render illusions useless.

If I'm an archmage relying on illusions, and you just invaded my lair, I'm perfectly happy to have you spend your concentration and an action on examining my Programmed Illusion(s) of me casting a spell while the actual me, wearing Nystul's Magic Aura of illusion magic, hits you with real spells (with no visual signature, like Hold Person). For example.

[DarknessEternal]

An illusion is neither a creature, nor an object. It is a non-solid figment*. As such, it does not register with Detect Magic. A non-invisible object affected by an illusion (such as changing the color of a self-destruct button from red to blue) would register.


This guy has it.

[Thunderous Mojo]

And I do get that this can also include using Detect Magic against some high level spells, but Magic Aura was literally designed for this. The thing is, people are accustomed to technology. If you walk past a guard that's using Detect Magic to weed out any infiltrators, they are not going to be looking for someone who foiled that simple, level 1 system. We barely do "double checks" in the real world (although I admit a lot of this is going to depend on your DM).

An Illusion of an object or creature is not a creature nor an object.
As written Detect Magic will detect nothing, (Nothing, Lebowski!),
from an illusory end-table, por exemplo.

"For the duration you sense the presence of magic within 30 feet of you. If you sense magic in this way, you can use your action to see a faint aura around any visible creature or object in the area that bears magic, and you learn its school of magic, if any."

Since the 14th level ability, Illusory Reality, makes an illusionary object real for 1 minute, a 'temporarily real object' probably should not 'glow' under the Detect Magic U.V. light.

Magic was used to alter reality, but once the alteration takes place, the newly created item, has it's own temporary inherent reality, and shouldn't glow under Detect Magic.

Unlike, prior D&D editions, that did seriously NERF Illusions...(cough, cough 3e)...5e Illusions are fairly robust, and not revealed by Detect Magic.

This is how I interpret the interactions between Detect Magic and Illusions.

[JonBeowulf]

And technically, the "presence of magic" includes
* Any spells you or your party has active
* (more controversially) any magic items you or your party has
* your ally's (or your own) familiar
* Etc.

That "ping" is binary, it's not radar. You know "there is magic nearby". Which, in the main, will be drowned out by the "sure, you're dripping with magic items" returns. Not where it is--it doesn't help localize it unless you do some careful triangulation in a noise-free environment. And free-standing illusory creations are neither creatures nor objects, so unless it's something like disguise self (or another spell cast on a creature or object), you can't use the second clause at all.

Okay, I forgot about these little details. Invisibility and illusion spells that state you create "an image of an object or creature" are safe. I'll accept that an illusory image of an object/creature is not an object/creature... which leads to a double-standard when targeting an illusory creature, but whatever. Illusion spells that don't contain that wording are up for debate, but I'm satisfied that DM is not as broken as I thought it was an hour ago.

EDIT: Man, I type slowly... 4 people submitted posts in the time it took me to reply to what PhoenixPhyre wrote. I think we're all saying the same thing now.

[Man_Over_Game]

An Illusion of an object or creature is not a creature nor an object.
As written Detect Magic will detect nothing, (Nothing, Lebowski!),
from an illusory end-table, por exemplo.

"For the duration you sense the presence of magic within 30 feet of you. If you sense magic in this way, you can use your action to see a faint aura around any visible creature or object in the area that bears magic, and you learn its school of magic, if any."

Since the 14th level ability, Illusory Reality, makes an illusionary object real for 1 minute, a 'temporarily real object' probably should not 'glow' under the Detect Magic U.V. light.

Magic was used to alter reality, but once the alteration takes place, the newly created item, has it's own temporary inherent reality, and shouldn't glow under Detect Magic.

Unlike, prior D&D editions, that did seriously NERF Illusions...(cough, cough 3e)...5e Illusions are fairly robust, and not revealed by Detect Magic.

This is how I interpret the interactions between Detect Magic and Illusions.

I'm inclined to disagree. It dulls down the counterplay, which can end up making the game less interesting. Having those interactions creates more interactions for players and plots to leverage to make things even more interesting. For example, emboldening Detect Magic actually adds more value to Magic Aura, another counterplay mechanic for the superior caster while integrating normal people as potential threats. And now your game is more interesting, rewarding those who take investments and risks.

Regardless of rules and semantics, a player would be frustrated that your ruling is inconsistent with every other interaction with this spell. It would feel like railroading without any benefit to the player. Why is that more fun for them?

If they are looking for traps everywhere, the "Good DM" answer isn't to just hide your traps better. You let them find what they're looking for! It makes them feel smarter for playing around what they suspected you would do to them, even if you hadn't intended on doing it in the first place.

Nerf Detect Magic when it proves to be too good, not because it's easy to jump to conclusions.


As an aside, it is worth noting that 5e isn't very consistent with the definition of "object". A window is an example object the rules describe, just like a chair. Any "expert" that argues about object semantics should use their talents to sit in the corner and figure out the Echo Knight for the rest of us. It'd be nice to see if someone could figure out exactly when object semantics start being a fun topic for a table.

[BRC]

As I'd rule it, Detect magic is quite good at spotting illusions, but only if you already suspect something to be an illusion.


That is, unless the Detect Magic is the ONLY magical effect active at the moment (Including magic items)

Exact wording, to be noted

For the duration you sense the presence of magic within 30 feet of you. If you sense magic in this way, you can use your action to see a faint aura around any visible creature or object in the area that bears magic, and you learn its school of magic, if any.

by default, you sense the presence, not the location, of Magic within 30 feet.

We'll say that Detect Magic does not detect itself, but if you have, say, a party member with a Familiar, or a +1 Sword, or, heck, some spell scrolls stashed away, then Detect Magic is going to perpetually be pinging you with "Yes, There is Magic active within 30 feet of you"

Now, you can spend your action every round to see what, specifically is magic, but that means that you're moving half-speed while travelling. I'd call that equivalent to stopping and searching for traps constantly.

So, if you walk into a room, and suspect you see an illusion, then two actions and a first-level spell slot will confirm it, but so will throwing a rock most of the time.

If you want to keep Detect Magic up, then you're spending a slot every 10 minutes, and moving slower because you're checking.


This means that it's not unreasonable to have, say, two low-level spellcasters guarding a door, taking turns ritual casting Detect Magic such that one of them is always up, and using his action each round to scan the surrounding area for Illusions or invisible people trying to sneak in. But that's hardly "Invalidating The School of Illusion".

[quindraco]

Okay, I forgot about these little details. Invisibility and illusion spells that state you create "an image of an object or creature" are safe. I'll accept that an illusory image of an object/creature is not an object/creature... which leads to a double-standard when targeting an illusory creature, but whatever. Illusion spells that don't contain that wording are up for debate, but I'm satisfied that DM is not as broken as I thought it was an hour ago.

EDIT: Man, I type slowly... 4 people submitted posts in the time it took me to reply to what PhoenixPhyre wrote. I think we're all saying the same thing now.

As a general rule, illusion spells that create something absolutely do create objects. The only ones I can think of that create a creature are Phantom Steed and Simulacrum, but there might be more. Illusion spells need not create anything - Blur and Invisibility don't, for example. But generally speaking, anything they do create is an object.

[Thunderous Mojo]

I'm inclined to disagree. It dulls down the counterplay, which can end up making the game less interesting.

Hmm...we both have counterplay concerns...having Detect Magic automatically detect illusions, mainly seems against the rules of the text, but also bypasses Illusion Counterplay*, chiefly, the Investigation check to determine that a visible phenomenon is an Illusion.

As a DM, I would have no issue with an ad hoc ruling, allowing a PC with Detect Magic active to have Advantage on their Investigation check, or even allow an Arcana Ability check to be substituted.

Allowing Detect Magic, to 'auto detect' illusions, essentially, eliminates the role an Inquisitive Rogue or any other Investigation based PC has invested in, and replaces this particular type of Investigation roll, with the nigh free resource cost of a 1st level Ritual Spell.

Magic is powerful enough in 5e, no reason to Nerf a PC with Expertise in Investigation, for an unnecessary boost to Detect Magic.

I always find it fascinating when a conversation reveals that participants have similar, underlying concerns, but reach very different, or diametrically opposed, solutions!
Viva la Différence!

M.O.G..... Think about the poor children, err Inquisitive Rogues!🃏

*Illusion Counterplay sounds like a Prog-Rock Band name*

[BRC]

Re: that Investigation check, I was curious what it was supposed to do

Since you can identify an illusion wiht any sort of physical interaction, and it seems odd to require an investigation check for "You poke the rock and your hand goes through it, determine if it is an Illusion"

I looked at the actual wording, and saw the following:


Physical interaction with the image reveals it to be an illusion, because things can pass through it. A creature that uses its action to examine the image can determine that it is an illusion with a successful Intelligence (Investigation) check against your spell save DC. If a creature discerns the illusion for what it is, the creature can see through the image.


The way I would rule that is that detect magic (or any form of basic physical interaction) can determine that something IS an Illusion, but the Investigation Check must be used to see THROUGH the illusion.


Similarly, I'd rule that Investigate can be used to identify an illusion even where you were not looking for one.

[Man_Over_Game]

M.O.G..... Think about the poor children, err Inquisitive Rogues!🃏

Ugh. I had to, once.

I thought it would be super interesting to have an Inquisitive Rogue in the party, since it meant I could do some really zany stuff.

What it really meant was that everyone (including the Rogue) were upset with me now that "Looking for stuff" actually costs an Action.

Just like Enthrall or that Thrall GOO power, it's just one of those things that really only works on paper or with a better DM than me.

[MrCharlie]

This thread was close, but didn't quite get there...
https://forums.giantitp.com/showthread.php?626508-Detect-Magic-Vs-Illusions-(and-casters-in-general)&highlight=detect+magic

I can find nothing RAW that contradicts the title. It seems a single 1st level spell totally ruins the entire School of Illusion.



You sense the magic is there (so Invisibility and similar are borked) and if you can see it, you know the school of magic (so all visible illusions are borked).

This feels broken and cannot be right... someone please tell me how I'm reading this wrong.
It never says that you know where the magic is, so you sense that there is magic-but cannot pinpoint it unless you take your action and its visible. Ergo, invisibility still works, but the player might be able to figure out that there is either A. Something invisible or B. Something obscured somehow. For an action, this is a perfectly valid use of the ability, and having a 30 foot magic alarm to know when to use it is a good play.

Of course, this only works if the party has no magic of their own, RAW, as you will constantly get pings from detect magic if they do. So they would need to remove all magical effects, then cast detect magic, see that there is still magic, then realize that something is under invisibility.

For visible illusions-using your action to see that they are illusion magic may be more efficient given that it's ranged, but you can always touch them or throw a dart at them.

I will say that knowing something magical is happening around you doesn't tell you it's an illusion. Also, even if they know there's an illusion, they won't know exactly what is illusive.

Example:

Players come to a rope bridge. It has a faint glow (I've given them reason to suspect magic)
Paranoid PC (PPC): I cast detect magic!
DM: You sense illusion magic

Now, the players will likely try to see if the bridge is real and if it can support them. Well they were going to do that anyways. Besides, the arch mage who conjured the illusive bridge is using Illusory Reality to make it real until they get halfway across. Then they learn to respect illusion more and depend on detect magic less.
Illusory reality does not, RAW, provide any mechanism to cancel it. You can still duplicate it with active use of the ability and a careful timing-illusory reality only lasts a minute, so if the archmage anticipates their move it can work-but he can't just turn it off.

Instead, have the archmage cast an illusion spell on the bridge that just makes the bridge look nicer-and also conceals that there are 7 barrels of gunpowder strapped to the underside of the bridge, concealed, which are triggered by weight on the far side. They see that its an illusion, may even dispel it, and then assume that the real trap was that the bridge was rickety. They probably don't even think to inspect it further. Then they carefully plod across, and...

The art of illusions is to exploit peoples assumptions, and to anticipate their actions before they happen. One of the best ways to do that is to make it so that the presence of the illusion itself is part of the trap-it does double duty as a distraction and means of concealment.

As another example-A massive towering golem pops out of the wall and roars at the party, slowly walking towards them. It seems to ignore all damage, so the wizard casts detect magic and sees that there is an illusion there. Laughing, he walks over and sticks his hand through the illusion-and the Mummy lord the illusion was cast on reaches out, grabs him, and gives him a big old hug.

[Mjolnirbear]

If you can target Mirror Image with Firebolt (because you don't know whether you hit the real one or the image until that's resolved) then illusory objects should likewise be targetable.

The 'it's not real so it's not an object' argument feels like "Firebolt all objects until you find the one that it works on, which is therefore a mimic/gargoyle/roper". It's an argument about technicalities that are also effectively metagaming.

I'm not actually against most metagaming. Your 14-year D&D veteran knows what to do with a troll; and there's lots of story reasons he might have to justify it. Should he pretend not to know? Why bother, as long as he doesn't spoiler the rest of the table. But mechanic-loophole-exploitation is like exploiting a bug in Skyrim to get a million items.

It hasn't come up in my games, but I'd rule that if you can see it, it counts as an object or creature for detect magic. Which means invisibility, blindness, darkness, fog cloud, or other heavy obscurement or invisibility spells are potentially immune from Detect Magic depending on positioning or line of sight.

And if course Magic Aura is a great way to screw with that too ;)

[Rukelnikov]

An Illusion of an object or creature is not a creature nor an object.
As written Detect Magic will detect nothing, (Nothing, Lebowski!),
from an illusory end-table, por exemplo.

"For the duration you sense the presence of magic within 30 feet of you. If you sense magic in this way, you can use your action to see a faint aura around any visible creature or object in the area that bears magic, and you learn its school of magic, if any."

Since the 14th level ability, Illusory Reality, makes an illusionary object real for 1 minute, a 'temporarily real object' probably should not 'glow' under the Detect Magic U.V. light.

Magic was used to alter reality, but once the alteration takes place, the newly created item, has it's own temporary inherent reality, and shouldn't glow under Detect Magic.

Unlike, prior D&D editions, that did seriously NERF Illusions...(cough, cough 3e)...5e Illusions are fairly robust, and not revealed by Detect Magic.

This is how I interpret the interactions between Detect Magic and Illusions.

Off topic but, I've been waiting for something akin to a Shadowcraft mage since 5e launched, or at least the old Shadow Evocation/Conjuration/Etc spells. I can't see how 5e has more to offer in the illusion department than 3.x did.

[Thunderous Mojo]

Off topic but, I've been waiting for something akin to a Shadowcraft mage since 5e launched, or at least the old Shadow Evocation/Conjuration/Etc spells. I can't see how 5e has more to offer in the illusion department than 3.x did.

3e was a very detailed, robust system, that lead to logical conclusions, that while imminently sensible, did not leave room for some concepts to be effective in play.

I'm going off memory here, (and admittedly am multi-tasking now, so I may be off), but 3e made granular distinctions between Illusion spells called Figments which relied upon fooling the senses of a creatures corporal form, and Illusion spells called Phantasms which bypassed corporal senses, and instead affected a creature's 'Mind'...which in the system had an existence separate from the corpus.

A DM, about to run an Undead Heavy Campaign, such as Paizo's Age of Worm's Adventure Path, would be remiss if they didn't warn players that wanted to play as an Illusionist or a Rogue..(Undead of course were immune to Critical Hits and Sneak Attack in 3e)...that they might wish to select different character concepts.

Demi-Shadow Magic only came about due to Illusionists having a limited spell list, that could be short circuited by Truesight, and thus Illusionists needed some way to "Keep it Real", and be able to effectively contribute.

Since 5e doesn't require Wizards to sacrifice being able to cast spells from "Opposition Schools" the pressure spells like Mind Blank or True Seeing place, respectively, on Enchanters or Illusionists is no longer insurmountable.

An Enchanter or Illusionist might need to 'switch' up the spells they use, but the option to use some different spells, is available. This was really not the case from 1e to 3e...being a Specialist truly limited your options, which required that spells that had similar effects, were created for each 'School of Magic'.

I'm an advocate for groups importing/creating their own spells. J.Crawford at heart is a 4th Edition D&D Designer, and seems to like iterating off the same limited range of effects.

Meanwhile, a spell like There/Not There from 2e AD&D's Tome of Magic,
(a book I use as inspiration even today), was never going to win Spell of the Year in Power-gamer/Munchkin Digest...but was downright weird and fun to use.

I hope this explains my viewpoint.✌️

[greenstone]

This means that it's not unreasonable to have, say, two low-level spellcasters guarding a door, taking turns ritual casting Detect Magic such that one of them is always up, and using his action each round to scan the surrounding area for Illusions or invisible people trying to sneak in.
That's cool! If I had players do that, I'd reward them somehow for good planning and tactics. Maybe have an ambush happen, but be totally spiled, due to their diligence.

[Addaran]

If you can target Mirror Image with Firebolt (because you don't know whether you hit the real one or the image until that's resolved) then illusory objects should likewise be targetable.

The 'it's not real so it's not an object' argument feels like "Firebolt all objects until you find the one that it works on, which is therefore a mimic/gargoyle/roper". It's an argument about technicalities that are also effectively metagaming.

I'm not actually against most metagaming. Your 14-year D&D veteran knows what to do with a troll; and there's lots of story reasons he might have to justify it. Should he pretend not to know? Why bother, as long as he doesn't spoiler the rest of the table. But mechanic-loophole-exploitation is like exploiting a bug in Skyrim to get a million items.

It hasn't come up in my games, but I'd rule that if you can see it, it counts as an object or creature for detect magic. Which means invisibility, blindness, darkness, fog cloud, or other heavy obscurement or invisibility spells are potentially immune from Detect Magic depending on positioning or line of sight.

And if course Magic Aura is a great way to screw with that too ;)

My thinking exactly. I get annoyed with the half casual english half specific keyword of 5ed because it makes everything so conplicated

I do think that detect magic will let you see that any visual illusion is in fact an illusion, if you can see it. Invisibility, you only know there's something but can't see where.

[BerzerkerUnit]

Point of information (sorry if I didn't see it above):

An Illusion of either a creature or an object is neither a creature nor an object, so detect magic would let you know "magic within 30 ft." Now what could the magic be? An action is used and reveals no auras. That leaves the player to wander around trying to pinpoint the source. Well if the magic is a hidden trap, that's a terrible idea.

If the illusion of a rock obscured a magical ring, the magic ring inside the rock would not be visible until the illusion (which detect magic, as stated, does not automatically reveal the presence of) was pierced with an Action used to make an investigation check. Good luck kicking rocks for 5 hours until you find one your foot passes through?

I've found DMing for Illusions works best when they are seen as options for creative problem solving when creatures react as their lore dictates or a way favorably shift the action economy.

Example:
I had a player that used Major Image to create a giant KFC colonel dual wielding chicken buckets to try and frighten away a Roc. I revealed that Rocs have traditionally been bred as mounts for Giants and this Roc in particular had lost its Cloud Giant rider ages ago, but recalled training time during which a giant with a bucket of treats at the ready would demand their attention. Instead of flying away, the Roc landed on the nearest edifice to await commands but it triggered a trap that occupied it while they fled. It was a creative if anachronistic solution.

I had a player create a Phantasmal Force that looked like a Bullette to challenge a real Bullette. I ruled the real Bullette would stand there continuously attacking the illusory challenger and eat the psychic damage for the full minute bc a Bullette's territorial nature and intellect doesn't allow for it to stop and think "heeeeyyyyyy, waaaaaiiiit a minute!" when it feels it's being challenged.

In combat, I've had players use various illusions and features to create phantom attackers often of the rogue (the character known to hit hardest after popping up unexpectedly). Enemies that "waste attacks" on such phantoms get to make their Investigation check. Even on a failure they might realize the phantom presents no threat when the real rogue pops up elsewhere or their attack passes through it, but that phantom will continue to block line of sight until they beat that DC.

Illusions in combat should be used to strategically waste enemy actions and DM's that rule enemies always just ignore them in combat are being unimaginative and vindictive in settings where casters are popping in and out of thin air as early as level 3 and rogues can seemingly pop out from behind any table or corner.

[Unoriginal]

Nystul's Magic Aura invalidates Detect Magic.

[quindraco]

Point of information (sorry if I didn't see it above):

An Illusion of either a creature or an object is neither a creature nor an object, so detect magic would let you know "magic within 30 ft."

This is false. Illusions that exist in space - e.g. we're talking about Minor Illusion, not Weird - are almost always objects. In fact, they're objects unless you're told they're creatures, as with Phantom Steed.

[Keravath]

Point of order: nothing in Illusory Reality suggests that you can un-real it at will, rather than having to wait for the 1 minute duration on the effect to expire. Not even ending the illusion early necessarily does it; there's a lot of DM call here. Now, the DM is controlling the archmage, but he should be aware of the precedent he's setting with the ruling.

It is likely a DM call. The text says "You can do this on your turn as a bonus action while the spell is ongoing. The object remains real for 1 minute." It isn't clear whether continued concentration on the spell is a requirement for the continued reality of the object. RAW, I would say you are probably right - the object remains for one minute whether or not the spell is maintained. However, I could easily see a DM ruling that if the illusion spell ends then so does the existence of the illusory reality.

[Cikomyr2]

First of all, yes. Detect Magic does invalidate illusions relying on deception.

if you are trapped in a Phantasm, detect magic would make you automatically disbelieve the harmful illusion, for sure.

But for long distant illusions? Detect magic has a range of 30 feet, so it's of little use.

Also, just because you know what you see/perceive is an illusion doesn't mean you can see what's true. You do not make the illusion disapear, unless the spell explicitly say a saving throw ends the spell. You just know that what you see is a fake.

[luuma]

"An Illusion of either a creature or an object is neither a creature nor an object, so detect magic would let you know "magic within 30 ft.""

This is false. Illusions that exist in space - e.g. we're talking about Minor Illusion, not Weird - are almost always objects. In fact, they're objects unless you're told they're creatures, as with Phantom Steed.

Can you give us a rule citation for this? How's it false?

Minor Illusion isn't "an illusion that exists in a space" - it doesn't occupy its space, doesn't need to be created in an unoccupied space, and doesn't seem to be intended to be an object - it's an "image of an object", is never referred to as an object, and things can pass through it. So I'd say that these illusions are not objects, and are not tethered to objects. Objects occupy their space.

As far as I'm aware, Detect magic can only detect the school of magic on "visible creatures or objects in the area that bear magic". Invisible creatures and objects can't be targeted, and illusions from silent image, minor illusion, major image, programmed illusion etc don't cause any creatures or objects to bear magic, so, RAW, all that Detect Magic tells you in those cases is "there's magic present within 30 feet of you". The same is true for spells like silence, dust devil and flaming sphere, none of which are tied to objects. Heck, even for phantasmal killer, all you are told is that *you* are affected by an illusion - the objects you perceive still appear entirely real to you, unless your character already has an inkling of what's happening.

I think the RAW for detect magic is a much nicer, more limited effect, and I'd like the effect to be limited because low-level intrigue campaigns are good fun and don't need any more mystery solving tools.

All that being said, I am a self contradictory b'stard, so I also rule that images of objects are targetable with stuff like firebolt. i.e, I rule that "choose a creature or object you can see within range" lets you choose images of creatures or objects. I do this because it's more fun, and makes the world feel more real, and less like a set of precisely worded mechanical interactions.

[Narsham01]

If you can target Mirror Image with Firebolt (because you don't know whether you hit the real one or the image until that's resolved) then illusory objects should likewise be targetable.

The 'it's not real so it's not an object' argument feels like "Firebolt all objects until you find the one that it works on, which is therefore a mimic/gargoyle/roper". It's an argument about technicalities that are also effectively metagaming.

I'm not actually against most metagaming. Your 14-year D&D veteran knows what to do with a troll; and there's lots of story reasons he might have to justify it. Should he pretend not to know? Why bother, as long as he doesn't spoiler the rest of the table. But mechanic-loophole-exploitation is like exploiting a bug in Skyrim to get a million items.

It hasn't come up in my games, but I'd rule that if you can see it, it counts as an object or creature for detect magic. Which means invisibility, blindness, darkness, fog cloud, or other heavy obscurement or invisibility spells are potentially immune from Detect Magic depending on positioning or line of sight.

And if course Magic Aura is a great way to screw with that too ;)

It is unclear based on the wording of Mirror Image that you can target the Image with Firebolt. The spell wording provides a specific mechanic which determines if an attack on the CASTER will hit the caster or an image. There is no comparable mechanic for the images, despite the fact that, if it is possible to be confused about your target trying to attack the caster and accidentally hit an image, it must also be possible to accidentally hit the caster when trying to deliberately pop an image. Personally, I would rule that you cannot deliberately target an image. You also can't use Detect Magic to identify the images, because the Mirror Image spell is cast on the caster, who would therefore have an illusion aura on them, and not on itself.

You clearly can attempt to attack an illusory goblin with a spell that only targets creatures, so while I think the interpretation that an illusion of an object is not an object, it's an ambiguous case. (The alternative--that you cannot cast Firebolt at an illusory goblin--allows a cantrip to expose an illusion.)

Personally, I would tend to rule that, if someone casts Detect Magic or has it running and is specifically scrutinizing an object or creature that is actually an illusion, the action spent via Detect Magic would trigger the Investigation check. You are, after all, examining an illusion and attempting to determine its characteristics. Whether or not you can pick up on the school is a secondary consideration. For that matter, illusions can incorporate a visual element, so might it be possible to include a visual element that either interferes with the aura reading aspect of Detect Magic or returns a false aura? If that seems ludicrous, consider that an illusion spell obviously incorporates color, despite that fact that not everyone viewing the spell can see all colors. A lot depends on what Detect Magic actually does, and the system doesn't define the mechanism through which it functions, though it is clearly a visual mechanism or you wouldn't need to see something to pick up its aura.

What of phantasms? A phantasmal creature is presumably a creature, but only to the target of the spell. Again, I'd rule that trying Detect Magic triggers the Investigation check, which sidesteps the knotty question about how the interaction should work.

[Kuulvheysoon]

Nystul's Magic Aura invalidates Detect Magic.

It's also, ironically, an illusion spell that specifically counters detect magic.

...If cast on a person or object. Which does limit it somewhat, but still. They tried?

[ATHATH]

For the duration you sense the presence of magic within 30 feet of you. If you sense magic in this way, you can use your action to see a faint aura around any visible creature or object in the area that bears magic, and you learn its school of magic, if any.
Okay, you can passively sense the presence of magic within 30 ft. of you, which we can assume also means that you can sense the amount of magic that's within 30 ft. of you (otherwise, this aspect of the spell would be nigh-useless). This can tell you that something magical has come within 30 ft. of you, but it doesn't tell you if that something someone's buff spell, a scrying sensor, a summoned creature, an illusion, a magic item, etc., nor does it tell you where it is (unless you take the time to triangulate its location).

In order to get more detailed information, you have to blow your action (which admittedly isn't a big deal outside of combat) and be able to see the magic-bearing creature or object. As someone else has probably mentioned, this has no effect on Invisibility, purely auditory illusions, etc. A RAW argument could probably be made that Major Image isn't a creature or an object, so Detect Magic can't see an aura around it, but that's a significant stretch.

[Segev]

Given 5e's emphasis on "rulings, not rules," I tend to believe that, despite the precise wording of the RAW, most DMs would let somebody hurl a firebolt or an eldritch blast or even a magic missile at a door, treasure chest, or illusions thereof, because the in-game narrative is not, "this spell has specific qualia it depends on things having to be able to lock onto them," but rather, "this spell creates a bolt of fire or force or whatever, and the mage directs it towards a designated point/along a particular line."

Put another way, it's no harder to hurl a spell at an illusory target than it is to point a crossbow at one.

The question of whether an image of an object created by an illusion is, itself, an object is another point, however, since - as in the case of detect magic - the quality of being "an object" actually is relevant based on what the spell is doing in-narrative. It's actually letting you see auras around objects.

I, personally, would argue that an image of an object is a phenomenon, not an object. This is a relevant distinction: minor illusion can create images of objects; silent image can create images of objects, creatures, and phenomena.

If you have detect magic up and are standing within 30 feet of a fog cloud spell's effect, does the cloud of fog have an aura, or is it just "there's magic nearby?" Fog clouds are "phenomena" rather than creatures or objects, I believe, in the taxonomy 5e uses. (No citations for this, I'm afraid, just my best interpretation based on context clues.)

[Xihirli]

If I cast an illusion, and your response is using your action and/or your concentration to cast Detect Magic, then using another action to tell that what I cast was an illusion, I have gotten a very good use out of that illusion I cast.

[Valmark]

It doesn't look like an effective counter to illusions to be honest.

First you need to either spend an action and a slot or take 10 minutes to cast it, then it takes your Concentration. Then consider this- it only tells you there is magic within 30 feet. The only way to know there is specifically illusions is for an object or a creature to be visible and have illusions on, since images shaped like objects/creatures aren't actually objects/creatures- that is a very restricted field.

[BerzerkerUnit]

This is false. Illusions that exist in space - e.g. we're talking about Minor Illusion, not Weird - are almost always objects. In fact, they're objects unless you're told they're creatures, as with Phantom Steed.

I respectfully disagree.

An illusion is by definition not the thing it appears to be, nor a thing itself, it is a spell effect that creates the illusion of the thing. You can call it an object for ease of reference in conversation “the illusory rock” but when someone attempts to interact with said “object”, they cannot, unless the spell dictates otherwise, which still does not make it an object. Even if the spell says it creates the illusion of an object, the illusion itself isn’t an object the way a photoreal sculpture of a person isn’t the person but is an object.

Phantom Steed does have specific rules about what it is, as does Illusory Dragon. But the other various Image spells are pretty consistent with Minor Illusion. I won’t get into discussion of Weird since it’s just terrible.

I guess if you’re willing to engage a real shallow semantics argument we can talk about what constitutes an object. Shovel? For sure. Ice Cube, definitely, a cubic foot of water? Okay. A cubic foot of Acid? If water is then this is, sure. How about an arbitrary volume of air at default atmospheric density. That is an object, I should think, what with it having a quantifiable mass. An illusion of said air would not have mass, and could not be breathable, though depending on level of effect, may inexplicably have a scent and apply sufficient wind resistance to induce discomfort at speed (but not damage).

A volume of Fire might be classified an object. Using my earlier standard of quantifiable mass I believe the photons released can be quantified on some barely conceivable scale, but an illusory fire would provide no warmth (the sensation of warmth may be possible at higher level, but won’t be real, so you might freeze to death by your illusory flames). It also won’t provide illumination, but since it can’t do that the idea of whether an illusion of fire could be made at all is something I imagine someone with more than my passing familiarity with chemistry would need to speculate.

[Segev]

I respectfully disagree.

An illusion is by definition not the thing it appears to be, nor a thing itself, it is a spell effect that creates the illusion of the thing. You can call it an object for ease of reference in conversation “the illusory rock” but when someone attempts to interact with said “object”, they cannot, unless the spell dictates otherwise, which still does not make it an object. Even if the spell says it creates the illusion of an object, the illusion itself isn’t an object the way a photoreal sculpture of a person isn’t the person but is an object.

Phantom Steed does have specific rules about what it is, as does Illusory Dragon. But the other various Image spells are pretty consistent with Minor Illusion. I won’t get into discussion of Weird since it’s just terrible.

I guess if you’re willing to engage a real shallow semantics argument we can talk about what constitutes an object. Shovel? For sure. Ice Cube, definitely, a cubic foot of water? Okay. A cubic foot of Acid? If water is then this is, sure. How about an arbitrary volume of air at default atmospheric density. That is an object, I should think, what with it having a quantifiable mass. An illusion of said air would not have mass, and could not be breathable, though depending on level of effect, may inexplicably have a scent and apply sufficient wind resistance to induce discomfort at speed (but not damage).

A volume of Fire might be classified an object. Using my earlier standard of quantifiable mass I believe the photons released can be quantified on some barely conceivable scale, but an illusory fire would provide no warmth (the sensation of warmth may be possible at higher level, but won’t be real, so you might freeze to death by your illusory flames). It also won’t provide illumination, but since it can’t do that the idea of whether an illusion of fire could be made at all is something I imagine someone with more than my passing familiarity with chemistry would need to speculate.

I feel the need to reitterate - not in argument with BerzerkerUnit, here, but just as this is a relevant point wrt the question he's expouding upon - that the category of "phenomena" also exists, in addition to "creature," "object," and "environment." I would argue that fire, at the very least out of the list of things discussed here, is a "phenomenon," not an "object."

[Person_Man]

Wait, is this news to people? I thought the intended RAW of Detect Magic was to flag illusions, magic traps, magic secret doors, magic items, magic disguises, shapeshifted creatures, mirror images, etc., and I've played it that way through multiple editions.

My opinion is that its literally the whole point of the spell, and is a microcosm of the entire game. DM sets up elaborate dungeons, magical creatures, engaging roleplaying encounters, and other interesting and dangerous stuff. Players use their their class abilities, spells, skills, and personal wits to figure them out. And critically, Detect Magic doesn't dispel anything. It just outlines it as magical. Just because you know an enemy is highlighted as magical, or a doorknob is magical, or a bridge is magical, it doesn't tell you what steps to take next. It's just a flag that magic is afoot and you should be extra paranoid, which is how every player should act all of the time anyway.

If anything, my observation has been that the utility and ubiquity of divination magic has been tremendously weakened in 5E. It's basically just a slightly more effective 10 ft pole.

[Reach Weapon]

I feel the need to reitterate - not in argument with BerzerkerUnit, here, but just as this is a relevant point wrt the question he's expouding upon - that the category of "phenomena" also exists, in addition to "creature," "object," and "environment." I would argue that fire, at the very least out of the list of things discussed here, is a "phenomenon," not an "object."

What do you mean? An African Aristotelian or a European Newtonian swallow fire?

[Segev]

What do you mean? An African Aristotelian or a European Newtonian swallow fire?

For purposes of D&D? Either. Though typically, we're dealing with Aristotelian, given that there's an elemental plane of the stuff.

[schm0]

To me the logic here is quite plain.

Detect magic does what it says on the tin. It detects magic.
If illusions are somehow immune to this spell, then they are categorically not magical, yet we know that is not true.
It makes very little sense that you can only detect the presences of an illusion through mundane means but not through magic.
The aura only works on visible creatures and objects. So no auras around invisible creatures, and no auras around the illusions themselves.




Ergo, you can detect the presence of a magical illusion through both mundane and magical means.

[Tanarii]

Re: that Investigation check, I was curious what it was supposed to do

Since you can identify an illusion wiht any sort of physical interaction, and it seems odd to require an investigation check for "You poke the rock and your hand goes through it, determine if it is an Illusion"

I looked at the actual wording, and saw the following:



The way I would rule that is that detect magic (or any form of basic physical interaction) can determine that something IS an Illusion, but the Investigation Check must be used to see THROUGH the illusion.
That's exactly my interpretation too.

[Thunderous Mojo]

If anything, my observation has been that the utility and ubiquity of divination magic has been tremendously weakened in 5E. It's basically just a slightly more effective 10 ft pole.

This has not been my experience at all, and the tone strikes me, as a bit too hyperbolic.

In 1e AD&D Detect Magic for a cleric took One Round to cast, not Segments, and only lasted a Turn. A cleric, for all practical purposes, couldn't use Detect Magic in combat situations in AD&D.

The Druid version of Detect Magic was better than the cleric's, (only took 3 Segments to cast and lasted 12 rounds). The Magic User version of Detect Magic only took one Segment to cast and had a duration of 2 rounds per level.

The 5e version of Detect Magic is fairly comparable to the AD&D Magic User version. While 5e Detect Magic, isn't a bonus action to use, many 1e spells that had a 1 segment casting time are not translated to 5e with a Bonus Action casting time.

The 5e version of Detect Magic can last 10 minutes, and is a Ritual spell, so using the spell may not require the expenditure of any spell slot resources at all.

A Wizard, doesn't even have to Prepare Detect Magic, they only need the spell in their repertoire, which is a wondrous gift, as it allows all the spellcasters in the party to Prepare/Learn different spell options.

A first level spell caster with the Ritual Caster feature, can right from Session One of the campaign, count on being able to have Detect Magic active. This wasn't at all remotely true in AD&D.

In 5e a PC can use their already active Detect Magic 'Spidey Sense' to vaguely determine there is Magic active in an area, such as a Glyph of Warding spell holding a Phantasmal Force spell.

If the PC triggers the stored Phantasmal Force spell, the PC merely needs to examine themself, to ascertain they now have an Aura of Illusion Magic on them, that wasn't present before....which could be a very informative piece of information to a savvy player.

This seems just as potent, if not more so, than Detect Magic in prior editions.

*Complete aside...Person_ Man..is your handle inspired by They Might be Giants?*

[PhoenixPhyre]

At the large cost of concentration.

However, I've noticed that warlocks in my game very frequently pick up the invocation for detect magic at will

I have some homebrew changes to detecting magic in general, but that's out of scope here.

[BerzerkerUnit]

I feel the need to reitterate - not in argument with BerzerkerUnit, here, but just as this is a relevant point wrt the question he's expouding upon - that the category of "phenomena" also exists, in addition to "creature," "object," and "environment." I would argue that fire, at the very least out of the list of things discussed here, is a "phenomenon," not an "object."

I will admit to 100% overlooking and/or forgetting "phenomena" as category. My hard and fast interpretation would be "can a person push on it with their hand and experience any perceptible resistance? Yes=object, no=phenomena. So a bolt of lightning, fire, blob of darkness- all phenomena. Horse, cart, fog bank, room full of air, ring- all objects. Some DMs might think air or fog cloud are phenomena rather than objects, and I'm fine with it. Another hard and fast rule: can Minor Conjuration conjure it or a part of it? Object.


Wait, is this news to people? I thought the intended RAW of Detect Magic was to flag illusions, magic traps, magic secret doors, magic items, magic disguises, shapeshifted creatures, mirror images, etc., and I've played it that way through multiple editions.

My opinion is that its literally the whole point of the spell, and is a microcosm of the entire game. DM sets up elaborate dungeons, magical creatures, engaging roleplaying encounters, and other interesting and dangerous stuff. Players use their their class abilities, spells, skills, and personal wits to figure them out. And critically, Detect Magic doesn't dispel anything. It just outlines it as magical. Just because you know an enemy is highlighted as magical, or a doorknob is magical, or a bridge is magical, it doesn't tell you what steps to take next. It's just a flag that magic is afoot and you should be extra paranoid, which is how every player should act all of the time anyway.

If anything, my observation has been that the utility and ubiquity of divination magic has been tremendously weakened in 5E. It's basically just a slightly more effective 10 ft pole.

I vigorously disagree with this interpretation. Detect magic is a good tool for recognizing magic traps, secret doors, and the potential presence of an illusion. But Illusions are, by design, supposed to obfuscate things and having a level 1 spell pierce even the most advanced spells automatically is laaaaaaammmmme. My interpretation calls for some effort to be made before you can be sure an illusion is at play (as opposed to a wand in a pocket, etc). The spell is still hugely useful in determining what kind of magic is at play and what kind of risk the party is willing to take. A spell glyph is abjuration, but a teleport glyph and a fireball glyph are two very different kinds of risk and Detect magic should tell you which kind you're dealing with. It should give you insight into the kind of magic item you're dealing with before having to identify it, and it still tells you "hold up, something is near..." even through walls.


To me the logic here is quite plain.

Detect magic does what it says on the tin. It detects magic.
If illusions are somehow immune to this spell, then they are categorically not magical, yet we know that is not true.
It makes very little sense that you can only detect the presences of an illusion through mundane means but not through magic.
The aura only works on visible creatures and objects. So no auras around invisible creatures, and no auras around the illusions themselves.


Ergo, you can detect the presence of a magical illusion through both mundane and magical means.

I don't think anyone has pitched detect magic not being able to detect the presence of an illusion, only that by default illusions do not meet the criteria for the Action portion of detect magic to determine exactly what is magical or identify the school. Admittedly, "hmmm there's some kind of magic, but I can't seem to determine what or where it is beyond this general area" is a fine way to justify the inference there is an illusion of some kind. I also think spending time orienteering is a fine way to narrow down exactly where the mystery magic is coming from, but like I said above, you'll have to kick a lot of proverbial rocks after that.

[Thunderous Mojo]

At the large cost of concentration.

Forgoing looking at one's phone while driving seems too large a sacrifice to many, until they have an accident.

If hostilities or another circumstance require a spellcaster to drop their concentration on Detect Magic, in order to cast another spell that also requires Concentration, this is a 'free action' that can occur at any time, (presumably on another's turn, no less), so this 'sacrifice' you speak of, seems a fairly trivial cost.

Vigilance isn't just the cost of freedom, it is also the cost to stay alive. 😉

[Zalabim]

Forgoing looking at one's phone while driving seems too large a sacrifice to many, until they have an accident.

If hostilities or another circumstance require a spellcaster to drop their concentration on Detect Magic, in order to cast another spell that also requires Concentration, this is a 'free action' that can occur at any time, (presumably on another's turn, no less), so this 'sacrifice' you speak of, seems a fairly trivial cost.

Vigilance isn't just the cost of freedom, it is also the cost to stay alive. 😉

It's not about the loss of Detect Magic when you use a different spell. It's the loss of every other [concentration] spell when you use Detect Magic. Any other effect anyone had that lasts for 10 minutes or less also ends if you ritual cast it.

[PhoenixPhyre]

It's not about the loss of Detect Magic when you use a different spell. It's the loss of every other [concentration] spell when you use Detect Magic. Any other effect anyone had that lasts for 10 minutes or less also ends if you ritual cast it.

Right. Got summoned creatures up? Lose them (or they go berserk for elementals). For warlocks who depend on hex, you lose hex.

This is a cost, and a significant one for some playstyles.

[MrCharlie]

I'd like to volunteer some meta commentary that the targeting rules for illusions not what they actually are and there untargetable by most effects is a debate that has been beaten to death, and we've entered that realm firmly with the detect magic discussion. The Tl;DR is that the rules break entirely on this level and you get all sorts of contradictions, paradoxes, and logical implausibilities.

[Thunderous Mojo]

It's not about the loss of Detect Magic when you use a different spell. It's the loss of every other [concentration] spell when you use Detect Magic. Any other effect anyone had that lasts for 10 minutes or less also ends if you ritual cast it.

Right...this is no different than any other spell that requires Concentration. 5e wants spellcasters to have to make hard choices 😉

Right. Got summoned creatures up? Lose them (or they go berserk for elementals). For warlocks who depend on hex, you lose hex.

This is a cost, and a significant one for some playstyles.

A berserk elemental, or demon, often creates chaos.....a chaos the party can likely exploit...."with great Concentration, comes Difficult Choices"...my Uncle Ben, taught me that...or I could have read it on a box of rice.🃏


. The Tl;DR is that the rules break entirely on this level and you get all sorts of contradictions, paradoxes, and logical implausibilities.

I disagree. Illusions not counting as actual objects or creatures leads to logical results. If you are getting a whiff of Magic from a stone wall through the ambient Magic detection power of Detect Magic, but are unable to see a magical aura....this is a fairly large clue that further Investigation is needed.

In 5e, needing to investigate further, vis a vis Illusions requires an actual Investigation Ability check, unless you have Truesight.

The flow of this game path is fairly smooth, which is the reason the designers made the game this way...Detect Magic helps gather information on Illusions, but rarely just straight up identifies them.

[Chronos]

If you are getting a whiff of Magic from a stone wall through the ambient Magic detection power of Detect Magic, but are unable to see a magical aura....
If you can't see a magical aura, then you have no way of knowing that the whiff of magic is coming from the stone wall. It might be from the floor, or the ceiling, or an invisible creature in the room with you, or a scrying sensor, or the +1 sword your fighter friend is carrying.

[BerzerkerUnit]

If you can't see a magical aura, then you have no way of knowing that the whiff of magic is coming from the stone wall. It might be from the floor, or the ceiling, or an invisible creature in the room with you, or a scrying sensor, or the +1 sword your fighter friend is carrying.

While you need a fairly large amount of room you can do some simple orienteering to figure out where the magic is coming from even if your action won’t reveal an aura.

[Thunderous Mojo]

If you can't see a magical aura, then you have no way of knowing that the whiff of magic is coming from the stone wall. It might be from the floor, or the ceiling, or an invisible creature in the room with you, or a scrying sensor, or the +1 sword your fighter friend is carrying.

Which all falls under: "Further Investigation Required". ✌️

If you can't see the magical aura surrounding the party's Magic Items...then you know something very, very, strange is occurring.

Science and Rational Inquiry often divine 'facts' about creatures, objects, and phenomena not from observing the creature, objects, and phenomena directly, but through noticing important context clues and piecing together the 'big picture' from what logically follows.

It is called investigation.

[PhoenixPhyre]

Which all falls under: "Further Investigation Required". ✌️

If you can't see the magical aura surrounding the party's Magic Items...then you know something very, very, strange is occurring.

Science and Rational Inquiry often divine 'facts' about creatures, objects, and phenomena not from observing the creature, objects, and phenomena directly, but through noticing important context clues and piecing together the 'big picture' from what logically follows.

It is called investigation.

But most of the time, you'll get the ping, think "oh, it's the party's magic items" and not investigate further. For it to really function as a warning flag, you have to have no party-side magic going at all, including magic items. You don't get a separate ping for each source, you only get a binary "yes, there is magic somewhere within 30'" or "no, there isn't magic within 30'" signal, whether it's one source or a hundred.

Or interpret the spell to only call out active spells, which solves some other issues (what school of magic is a trap from if it doesn't cast a spell?) at the cost of neutering the spell for most purposes. Because active spells are much rarer than (as they are a strict and lesser subset of) "magical objects, traps, etc".

[Segev]

Most of the time, I have seen people cast Detect Magic when they have something specific they want to examine. It stands to reason hey would focus on something at that point.

[Thunderous Mojo]

But most of the time, you'll get the ping, think "oh, it's the party's magic items" and not investigate further.

I would classify that as a sloppy investigation.

You see this in automotive repairs all the time. A 'mechanic' will plug in a diagnostic tool into a vehicle's OMBD II port and take the Error Code as gospel.

The Error Code might say "Fuel Pump Failure" or "Piston Compression Failure", which the Tech takes as fact, without considering that the manufacturer states that there are multiple ways that error code can be triggered.

The shop gets you to replace a perfectly fine Fuel Pump, when the real culprit was a faulty Oxygen Sensor. The fuel pump replacement is substantially more expensive than replacing a bum sensor...so the shop profits in what economics calls "Moral Hazard"...poor behavior in this case is more profitable than being competent.

The PCs may not have the luxury of a "Moral Hazard" windfall...as sloppy investigation very well may lead to death or worse.

If reducing Exploration Tier challenges to casting a single spell, or rolling a few Perception/Investigation rolls to receive the 'right answer' works for you and your game...then go with what works for your game.

Most of my players would not enjoy this style of play. Indeed, some would characterize it as "Railroading" or "Leading Them by the nose".
They want their character's abilities to influence what type of clues they can gather, but want to solve the 'puzzle' themselves...it is what they find fun.

If someone's group doesn't find that fun...by all means having Detect Magic streamline the process is a decent solution for that group.

[PhoenixPhyre]

I would classify that as a sloppy investigation.

You see this in automotive repairs all the time. A 'mechanic' will plug in a diagnostic tool into a vehicle's OMBD II port and take the Error Code as gospel.

The Error Code might say "Fuel Pump Failure" or "Piston Compression Failure", which the Tech takes as fact, without considering that the manufacturer states that there are multiple ways that error code can be triggered.

The shop gets you to replace a perfectly fine Fuel Pump, when the real culprit was a faulty Oxygen Sensor. The fuel pump replacement is substantially more expensive than replacing a bum sensor...so the shop profits in what economics calls "Moral Hazard"...poor behavior in this case is more profitable than being competent.

The PCs may not have the luxury of a "Moral Hazard" windfall...as sloppy investigation very well may lead to death or worse.

If reducing Exploration Tier challenges to casting a single spell, or rolling a few Perception/Investigation rolls to receive the 'right answer' works for you and your game...then go with what works for your game.

Most of my players would not enjoy this style of play. Indeed, some would characterize it as "Railroading" or "Leading Them by the nose".
They want their character's abilities to influence what type of clues they can gather, but want to solve the 'puzzle' themselves...it is what they find fun.

If someone's group doesn't find that fun...by all means having Detect Magic streamline the process is a decent solution for that group.

I'm confused. I'm not talking about any of that. I'm simply saying that detect magic, as written, really doesn't help the standard party be alerted to possible threats unless the caster is always checking on every visible object (or unless the party has exactly 0 ongoing magical effects, including items). And if the party has any magic, they can never know if a new magic effect shows up unless they happen to have it visible at that exact moment and be spending their action to focus on it[1]. Or one of many goes away. The information channel is saturated as soon as a single magic item or effect is within the radius. Going from 9 to 10 or 9 to 1 or 1 to 100 all act exactly the same, specifically that the caster gets no notice that anything's changed.

And even if you focus, you'd only see new sources (and only if you remembered exactly every single thing your allies were carrying that might ping).

Basically, detect magic, as written, is really minor. It helps a lot if there is one specific thing you can see that you have concerns about whether it's magical. It isn't a good tool to help you figure out what to investigate, unless your party has zero magic or you've ruled that it only picks up spells (in which case you've neutered it in other ways). That's all.

[Thunderous Mojo]

Basically, detect magic, as written, is really minor. It helps a lot if there is one specific thing you can see that you have concerns about whether it's magical. It isn't a good tool to help you figure out what to investigate, unless your party has zero magic or you've ruled that it only picks up spells (in which case you've neutered it in other ways). That's all.

Or the party stands 30' back away from the person that cast Detect Magic, and also holds the caster's Magic Items, or the party uses Leomunds Secret Chest to store their items in during the examination, or the table decides to 'hand wave away' the aspects of the spell they would rather not deal with.

I'm not seeing much disagreement in our understanding of Detect Magic to be honest. ✌️

[PhoenixPhyre]

1) Or the party stands 30' back away from the person that cast Detect Magic, and also holds the caster's Magic Items, or the party uses Leomunds Secret Chest to store their items in during the examination, or 2) the table decides to 'hand wave away' the aspects of the spell they would rather not deal with.

I'm not seeing much disagreement in our understanding of Detect Magic to be honest. ✌️

1) How do you know you need to do that? That's the issue. You need to know you have to investigate before detect magic becomes useful. It's helpful once you have something to investigate. It doesn't help you know that you need to investigate in the first place.

2) Yes, if you decide to ignore all the restrictions, most things get more useful.[1]

We may be in furious agreement here. I had understood you to be saying that detect magic was great at helping you know to look deeper. If so, we disagree. I do agree that it is useful once you're already investigating something specific. At a significant cost, however (concentration, time XOR spell slots XOR invocation choices).

[1] I've actually added to it in different ways, letting it see traces of past magic, as well as hints beyond the schools...because the schools of magic add no value IMO and are annoying to determine for non-spell magic, which is most of what they encounter.

[Thunderous Mojo]

We may be in furious agreement here. I had understood you to be saying that detect magic was great at helping you know to look deeper. If so, we disagree. I do agree that it is useful once you're already investigating something specific. At a significant cost, however (concentration, time XOR spell slots XOR invocation choices)..

I think it is a discussion in search of a disagreement, honestly. 😉
You 1st post on page 1 is your Ping post..which is an accurate account to my mind.

I think the only thing we might have a minor disagreement on is the 'significant cost' of Detect Magic....I don't think Detect Magic has any more significant cost than any other spell that requires Concentration.

If, PhoenixPhyre, you consider any spell with a Concentration requirement as having a significant cost, and are not stating that Detect Magic has more significant costs than other Concentration spells.....well we agree there as well.

We both seem to feel that Detect Magic doesn't autodetect illusions, and we both seemingly feel Detect Magic has limited investigatory prowess...(I've never said Detect Magic was great...but it is useful)....I do think 5e Detect Magic is better than 1e AD&D's version of the spell, (especially for clerics).

All in All, I think we are in "furious agreement" 👍

Thanks for the discussion, I don't want to take up anymore bandwidth in this thread, as I've been verbose enough, already.

[MaxWilson]

But most of the time, you'll get the ping, think "oh, it's the party's magic items" and not investigate further. For it to really function as a warning flag, you have to have no party-side magic going at all, including magic items.

Including Detect Magic?

[Reach Weapon]

Including Detect Magic?

That's certainly a fair question given how some say they're ruling it.

I'd argue that "sense[ing] the presence of magic" implies a general direction, like hearing a sound, smelling a stink or feeling a change in air currents. Further, given 5E targeting rules, "within 30 feet of you" does not include items that are considered part of you, so your gear shouldn't interfere. I'd cap this all off by claiming this is an as written interpretation of the spell, and not just a reaction to how annoying I'd find less accommodating versions.

[Chronos]

The Detect Magic spell clearly can't detect itself, or that initial ping of "there's magic present" would be completely useless. That's necessary to make the spell functional at all. But that doesn't mean that other spells on the party, or magic items, or whatever, wouldn't interfere.

[PhoenixPhyre]

The Detect Magic spell clearly can't detect itself, or that initial ping of "there's magic present" would be completely useless. That's necessary to make the spell functional at all. But that doesn't mean that other spells on the party, or magic items, or whatever, wouldn't interfere.

That's my interpretation, at least if I'm being formal. I'm generally much less so with that spell. Because I like giving information and seeing what they do with it. Secrets are much less fun then cryptic information that they only figure out later.

[OldTrees1]

If you are using Detect Magic as a warning system, then you are spending your Action every turn to "use your action to see a faint aura around any visible creature or object in the area that bears magic, and you learn its school of magic, if any" which means you can readily detect if a new visible creature/object is magical.

I don't see how the party having magic would get in the way. You can even see when they gain new auras.

For example, Dun the Dungeon Tour Guide used
Action: Detect Magic
Bonus Action: Mage Hand Legerdemain (search for traps)
Movement: Move forward slowly

[Segev]

That's my interpretation, at least if I'm being formal. I'm generally much less so with that spell. Because I like giving information and seeing what they do with it. Secrets are much less fun then cryptic information that they only figure out later.

I feel it worth pointing out that the context of the thread topic is whether detect magic detects and identifies illusions as illusions by examining the illusion with detect magic active.

In that context, it's really less about secrets vs cryptic information than it is about whether illusions have a shot of fooling the caster of detect magic at all. It's also worth noting that he has to think to cast it and to study the illusion, even if it can detect the illusion. At that point, you could argue that this is the Investigation check when all other avenues to investigate are inapplicable (e.g. an illusory beholder hovering and threatening the party and continually dodging their attacks).

[OldTrees1]

I feel it worth pointing out that the context of the thread topic is whether detect magic detects and identifies illusions as illusions by examining the illusion with detect magic active.

In that context, it's really less about secrets vs cryptic information than it is about whether illusions have a shot of fooling the caster of detect magic at all. It's also worth noting that he has to think to cast it and to study the illusion, even if it can detect the illusion. At that point, you could argue that this is the Investigation check when all other avenues to investigate are inapplicable (e.g. an illusory beholder hovering and threatening the party and continually dodging their attacks).

So something like
Hmm, that flaming sword, while it does have a necromancy aura, it does not have an evocation aura. Are those flames real?
*Roll Investigation*

or
Hmm, that flying sword does not have a magical aura, is it real? (I am assuming Detect Magic can't reveal the aura around things that are not real)
*Roll Investigation*

[Hilary]

My ruling has always been - the detect spell must be a higher level than the obscure spell to detect it.

This applies to everything: illusions, detecting to see if a stature is actually a petrified person, evil auras, etc.

[Thunderous Mojo]

Including Detect Magic?
👍👍👍

My assumption is that people able to cast Detect Magic are akin to experienced Radar Operators, they know how to interpret the raw data to account for radar echoes from clouds, and other identified planes.

If running Detect Magic by RAW, in effect, renders the spell useless, it is probably time to reinterpret the spell to allow it to be useful.

[Reach Weapon]

I can find nothing RAW that contradicts the title. It seems a single 1st level spell totally ruins the entire School of Illusion.

Backing up to the original premise for a moment, something like half the spells in the School of Illusion shouldn't be impacted by Detect Magic1, about a fourth might be better understood as being foiled by investigation2, and the remaining fourth might be involved in schemes that could be foiled by knowing illusions were involved3 but are otherwise not impacted, with one spell I've classified as insufficiently described in this regard and the other foiling Detect Magic4. I think the school itself is hardly invalidated.


1. Color Spray (1st), Blur (2nd), Invisibility (2nd), Mirror Image (2nd), Phantasmal Force (2nd), Shadow Blade (2nd), Silence (2nd), Fear (3rd), Hypnotic Pattern (3rd), Phantom Steed (3rd), Greater Invisibility (4th), Phantasmal Killer (4th), Dream (5th), & Mental Prison (6th)
2. Minor Illusion (Cantrip), Disguise Self (1st), Silent Image (1st), Major Image (3rd), Hallucinatory Terrain (4th), Seeming (5th), Programmed Illusion (6th), Project Image (7th), & Illusory Dragon (8th)
3. Distort Value (1st), Illusory Script (1st), Magic Mouth (2nd), Creation (5th), Mirage Arcane (7th), Simulacrum (7th), & Weird (9th)
4. Mislead (5th) and Nystul's Magic Aura (2nd), respectively.