I recently noticed a spelled called Switcheroo, and it gave me an idea. Let's say I make a Trickery Domain 2024 Cleric Owlin. First turn, I fly up 30ft, then use my BA to use Invoke Duplicity 30ft up, so 60ft high, and cast Mind Sliver on an enemy. Next turn, I move the duplicate up to 90ft high, then cast Switcheroo through my duplicate using the Invoke Duplicity: Cast Spells trait (meaning that as the spell is cast, the duplicate's position is considered mine), causing the enemy to switch positions with my duplicate on a failed save, and take a 90ft fall, for 9d6 bludgeoning damage. And that's assuming there's no chasm over which I can simply send my duplicate...
Invoke Duplicity allows you to cast spells as if you were in the duplicate's space, but it doesn't change anything else about the spell. A strict reading of the text of Switcheroo might suggest that because it says you and the target switch places, the target's going to end up where you are, not where the duplicate is. I think you could argue it either way.
The exact wording of the spell is "instantly teleport to your space".
Isn't this precisely what the Invoke Duplicity: Cast Spells changes? Making it so that, as far as casting spells is concerned, "my space" is the illusion's space.
Also, as I'm thinking about this way of reading it, claiming that you and your location or your space are distinct readings and it can be used to deny some interactions with spells that use the player's location, I'm not sure this particularly conservative interpretation changes anything.
Because I could use that same conservative interpretation to say that Invoke Duplicity: Cast Spells says I cast spells as though me, the actual PC, were in the illusion's space, not that our spaces are swapped. And so even though the spells says me and the target switch places (which it actually doesn't, but some spells like Command: Approach actually word it this way), it should still consider the illusion for any effect involving the player's location.
Because if you don't, that means you're using 2 distinct definitions for the word "you" in the spell's description and the word "you" in Invoke Duplicity: Cast Spells. And I can't think of any justification for doing that.
The way I understand Invoke Duplicity (or Gaze of Two Minds, since it's similar), you cast from the illusion's space, but your actual position remains the same for the proposed interaction.
I disagree. What you say is true, but it doesn't change much. "as though" means "it's not, but you pretend it is". That's quite literally the meaning of "as though". When you have something that says "as though", the actual state of things doesn't matter. You treat things "as though" they were in the proposed way.
And that's how I read Switcheroo. I cast it as though I was in my duplicate's space. So when it comes to resolve where the enemy goes, it goes where I would have been, that is to say the illusion's space. There is no reason to believe that casting from the illusion's space would have no consequences on the spells being cast. I think that's adding an arbitrary limitation.
Oh, but I'm realizing something... It's only the locations that are swapped, not the actual being. If I was in the illusion's space, it would still be me who would end up in the enemy's place, and not my illusion. That being said, my plan would still work, because the important part would be to send the enemy where my illusion is, and if I'm considered in the illusion's space as I'm casting the spell, then that's exactly what should happen.
It's just that my illusion would stay where it is (wouldn't be an issue since the illusion doesn't occupy its space), and it would be me who would end up where the enemy previously was. Plus, after level 6, I can always use my bonus action to swap places with my illusion anyway.
Both readings seem equally valid depending on how you interpret the Cast Spells ability.
1: The illusion serves as a full replacement for you in the spell 2: The illusion serves as the point of origin of the spell, largely impacting the range of the spellcasting
So... There's already issues with that ability. For instance:
-Gust of Wind and Misty Step are both Self spells -If point 1 is correct, then Gust of Wind can be centered on the illusion, but you can't teleport with Misty Step while using that ability, only the illusion can -If point 2 is correct, then you can teleport within 30 feet of your illusion with Misty Step, but casting Gust of Wind from the illusion's position still centers it on you
Ask your DM how it'll work and be consistent, I guess. Can't have it both ways.
Basically: Either you can use the ability to cast Misty Step or you can use Switcheroo to swap a person with the illusion. Can't do both, that comes into a rules conflict.
I don't think your reading #1 can be argued. Invoke Duplicity makes it quite clear that you are still casting the spell, but you do so from the illusion's position. It's not your illusion casting the spell.
It might be easier to picture it by simply pretending that the player actually is in the illusion's space (which by the way is what the description says we should do anyway), and wonder what would happen then.
Misty Step: you teleport where you want to go, making no difference with using it normally.
Gust of wind: the gust originates from where the illusion is.
Switcheroo: the enemy is teleported where your illusion is, you are teleported where the enemy was, and your illusion is still in the same place.
I cannot read the spell, but the Invoke Duplicity question is interesting in its own right..
And I read it as the spell's origin point is the illusion's space, with all that entails, so you can misty step up to 30 feet from its location, no matter where you are in relation.
The question for Switcheroo would depends on whether the spell's origin point matters for anything but range. The likely answers seem to be:
Target swaps places with you, the caster
Target ends up in the duplicate's space, you end up in the target's
Duplicate and target switch positions
Without the actual text, I can only speculate, but 1 and 3 seem most in line with the spirit of the ability.
(And frankly, the Misty Step trick is much more interesting than the Switcheroo one, which you don't need the duplicate to do in the first place, since you can fly. )
I don't think your reading #1 can be argued. Invoke Duplicity makes it quite clear that you are still casting the spell, but you do so from the illusion's position. It's not your illusion casting the spell.
It might be easier to picture it by simply pretending that the player actually is in the illusion's space (which by the way is what the description says we should do anyway), and wonder what would happen then.
Misty Step: you teleport where you want to go, making no difference with using it normally.
Gust of wind: the gust originates from where the illusion is.
Switcheroo: the enemy is teleported where your illusion is, you are teleported where the enemy was, and your illusion is still in the same place.
Gust of Wind would originate from where you are according to your examples, not from the illusion. That's the thing.
A Line of strong wind 60 feet long and 10 feet wide blasts from you in a direction you choose for the duration.
It doesn't matter what the point of origin was. It matters where you are. That's what I'm saying: The reading that lets you use Misty Step from the illusion's space also stops you from using Gust of Wind from its space. The reading that lets you use Gust of Wind from the illusion's space stops you from using Misty Step from the illusion's space because that treats the illusion as you for the purposes of the spell, so the illusion teleports instead.
Gust of Wind would originate from where you are according to your examples, not from the illusion. That's the thing.
I understand what you're trying to say. But I don't think it works that way, because in order to interpret it the way you are, you would need to make a distinction between "you" and "your location" for the context of the spell, without making it in the context of Invoke Duplicity. You'd need to read these 2 descriptions with different interpretations of the word "you", which would be inconsistent. That's why I think it makes no difference.
If you're saying "oh no, it uses your actual location because the spell says "you" in its wording", then you're saying that this wording matters in the spell description, but not in Invoke Duplicity's description. That makes no sense. If you're gonna make that distinction, you need to make it everywhere, including in Invoke Duplicity's description, and in the end it changes nothing.
Because when you say "it originates from you", you're supposed to be reading that in a context where you're already assuming that "you" is located in the illusion's space.
A Line of strong wind 60 feet long and 10 feet wide blasts from you in a direction you choose for the duration. ... As a Bonus Action on your later turns, you can change the direction in which the Line blasts from you
in that context, as you read that line, that "you" is assumed to be located where your illusion is.
Briefly surrounded by silvery mist, you teleport up to 30 feet to an unoccupied space you can see.
these "you" are again assumed to be located where your illusion is. But it's still you who are going to be teleported, because no matter where you are located, "you" is still "you". So no, it wouldn't teleport your illusion. It's not a "complete replacement" as you suggest, you're simply assuming that you, the player, are located where your illusion is.
Again, if you're gonna make that "you" and "your location" distinction, you also have to make it when reading Invoke Duplicity.
Cast Spells. You can cast spells as though you were in the illusion’s space, but you must use your own senses.
so the highlighted "you" in this reading should also be read as "you", the player. And I'm not highlighting the others because only the highlighted one is concerned by "as though". You're supposed to use your imagination for a moment and assume that you are not where you are, but where your illusion is instead.
I cannot read the spell, but the Invoke Duplicity question is interesting in its own right..
And I read it as the spell's origin point is the illusion's space, with all that entails, so you can misty step up to 30 feet from its location, no matter where you are in relation.
I agree with this.
Also, I think Invoke Duplicity should work with "Range: Self" spells to be advantageous for the cleric. This is my opinion from a different thread:
[...] Yes, the caster is not where the illusion is, and yes, the spells are still cast by the caster. But when it comes to where the spells are located (including their spatial origin), it's the illusion's location that should be considered, not the caster's. Because that's what Invoke Duplicity says. [...]
I agree with you.
Invoke Duplicity behaves similarly to Gaze of Two Minds:
While perceiving through the other creature’s senses, you benefit from any special senses possessed by that creature, and you can cast spells as if you were in your space or the other creature’s space if the two of you are within 60 feet of each other.
With Gaze of Two Minds, you can use the other creature's space to cast Eldritch Blast or Chill Touch, for example, as if you were there.
I would be surprised if, as a Cleric, you couldn't use Cure Wounds (a Touch spell) or Aura of Vitality (*) thanks to Invoke Duplicity. Concentration spells were actually mentioned in the pre-release video (around 25:17), and I think for a good reason New Cleric | 2024 Player's Handbook | D&D:
"[...] you can now summon up your illusory duplicate as a bonus action instead of an action, and you do not have to concentrate on it anymore [...] the combination before of it taking your entire action and you having to concentrate on it meant you were in some ways being shut down in two ways: you were spending in a whole turn bringing it out and then you couldn't at the same time have any of the clerics really nice concentration spells going simultaneously [...]"
(*) disclaimer: I'm aware about the creature/object discussion for Emanation.
Gust of Wind would originate from where you are according to your examples, not from the illusion. That's the thing.
I understand what you're trying to say. But I don't think it works that way, because in order to interpret it the way you are, you would need to make a distinction between "you" and "your location" for the context of the spell, without making it in the context of Invoke Duplicity. You'd need to read these 2 descriptions with different interpretations of the word "you", which would be inconsistent. That's why I think it makes no difference.
If you're saying "oh no, it uses your actual location because the spell says "you" in its wording", then you're saying that this wording matters in the spell description, but not in Invoke Duplicity's description. That makes no sense. If you're gonna make that distinction (which frankly, I don't think we should, because I feel it distorts the intent rather than reveal it), you need to make it everywhere, including in Invoke Duplicity's description, and in the end it changes nothing.
Because when you say "it originates from you", you're supposed to be reading that in a context where you're already assuming that "you" is located in the illusion's space.
A Line of strong wind 60 feet long and 10 feet wide blasts from you in a direction you choose for the duration. ... As a Bonus Action on your later turns, you can change the direction in which the Line blasts from you
in that context, as you read that line, that "you" is assumed to be located where your illusion is.
Briefly surrounded by silvery mist, you teleport up to 30 feet to an unoccupied space you can see.
these "you" are again assumed to be located where your illusion is. But it's still you who are going to be teleported, because no matter where you are located, "you" is still "you". So no, it wouldn't teleport your illusion.
Sorry, I didn't see your reply before.
I agree with you on your interpretation of Invoke Duplicity and its interaction with Misty Step and Gust of Wind.
So maybe I'm just splitting hairs regarding Switcheroo, and I could also agree with your way of ruling it.
The "you" in the spell is still you. For instance, if you cast Mirror Image, it's not the duplicate that gets the images. Some spells just don't work as well as others with this ability, and that's something you have to face. While you're casting as if from that space, there's a difference between casting a spell and resolving spell effects. The casting lets it originate from that spot, but that's as far as it goes.
Essentially: "You" are still you. The position only matters for where you're casting from, for the sake of spell range and origin point. Back to my Gust of Wind example, the wind would still originate from you for the same reason that Mirror Image still applies to you.
I already made the "you" is still "you" point in my own reply, and while I agree with the way you're reading Mirror Image, I still disagree with the way you read Gust of Wind.
But I can understand why you see it this way. You're assuming that this transposition would only last for the moment that the spell is cast, but wouldn't last for the concentration period.
And that would be a valid reading, were it not for the pre-release video that TarodNet mentioned, which indicates that the assumption of transposition should be kept while concentrating on a spell you cast this way:
I would be surprised if, as a Cleric, you couldn't use Cure Wounds (a Touch spell) or Aura of Vitality (*) thanks to Invoke Duplicity. Concentration spells were actually mentioned in the pre-release video (around 25:17), and I think for a good reason New Cleric | 2024 Player's Handbook | D&D:
"[...] you can now summon up your illusory duplicate as a bonus action instead of an action, and you do not have to concentrate on it anymore [...] the combination before of it taking your entire action and you having to concentrate on it meant you were in some ways being shut down in two ways: you were spending in a whole turn bringing it out and then you couldn't at the same time have any of the clerics really nice concentration spells going simultaneously [...]"
But I'll agree that at this point, it's no longer RAW. Because the way Invoke Duplicity worded, it's unclear whether the assumption of transposition is kept during the concentration, and as a DM, you can choose to interpret it either way, pre-release video or not.
The "you" in the spell is still you. For instance, if you cast Mirror Image, it's not the duplicate that gets the images. Some spells just don't work as well as others with this ability, and that's something you have to face. While you're casting as if from that space, there's a difference between casting a spell and resolving spell effects. The casting lets it originate from that spot, but that's as far as it goes.
Essentially: "You" are still you. The position only matters for where you're casting from, for the sake of spell range and origin point. Back to my Gust of Wind example, the wind would still originate from you for the same reason that Mirror Image still applies to you.
But if you rule it that way, most spells won't work with Invoke Duplicity or Gaze of Two Minds:
- Fireball: "A bright streak flashes from you..." - Eldritch Blast: "You hurl a beam of crackling energy"
And all the "Self: Range" spells would be useless, when that kind of range means:
A spell’s range indicates how far from the spellcaster the spell’s effect can originate [...]
Self. The spell is cast on the spellcaster or emanates from them, as specified in the spell.
So, when using your Duplicity, the spell is cast as if the Duplicity were the caster. The same should apply to "Range: Touch" or when using a Distance.
I think it's one of these cases where a strict RAW ruling would break the intent of the feature in a way that is just too obvious to ignore.
I remember a while ago, shortly after I joined this forum, I tried to make a case that Stone Shape could be used to create an object in absolutely any dimension, because the way it's worded, the "5ft cube" dimension limitation is only explicitly stated to apply to the stone you're shaping in its initial state, but there's no mention of a limit for the dimensions of the object that you're shaping the stone into, so you'd be able to take a 5ft cube of stone and reshape it into a 20ft long bridge, for example. It took a tweet from one of the designers to shut me up on that issue, confirming that the spell was not intended to be used in such a way.
I think it's the same thing here. If you read it as pedantically as possible, concentration spells can only be cast from the point of view of the illusion during the spellcasting time, but after that, it would come back to your actual self while you concentrate on it... But it just looks too absurd to be how the feature is intended to work.
The video talks about concentration only because the cleric is now able to use concentration spells (such as the updated Spiritual Weapon) alongside the duplicate now. It says nothing about any interaction between concentration spells and the duplicate beyond the fact that you can use both now.
But it's clear you're intent on reading this in whatever way benefits you most on a spell-to-spell basis, so I have no reason to continue.
I'm not projecting intent onto you, so don't project intent onto me. That's just rude. But just imagine it happen, it would obviously look nonsensical. You can't say "oh you're just biased" simply because you won't make that effort.
Plus, I don't really care about Gust of Wind. I never use that spell. My initial question was about Switcheroo, which is not a concentration spell, and we've already agreed it should indeed teleport the enemy where the illusion is. I don't have any stakes in the rest of this discussion, but even if I had, it wouldn't be my first time admitting that I can't do what I projected to do.
The target must succeed on a Charisma saving throw or instantly teleport to your space whilst you teleport to the one it previously occupied.
In which case, the RAW reading is:
Target ends up in the duplicate's space, you end up in the target's.
You remain you for the purposes of the teleport, but your location is considered to be that of the duplicate.
That said, I wouldn't judge a GM who decided that was too weird, and still had the target swap with the player, or even the duplicate.
The tactic that started this thread works, since it appears the designers of the spell didn't include a protective clause like there is in Vortex Warp (I wonder if they included something to prevent swapping huge creatures into a space that won't hold them?)
I recently noticed a spelled called Switcheroo, and it gave me an idea. Let's say I make a Trickery Domain 2024 Cleric Owlin.
First turn, I fly up 30ft, then use my BA to use Invoke Duplicity 30ft up, so 60ft high, and cast Mind Sliver on an enemy.
Next turn, I move the duplicate up to 90ft high, then cast Switcheroo through my duplicate using the Invoke Duplicity: Cast Spells trait (meaning that as the spell is cast, the duplicate's position is considered mine), causing the enemy to switch positions with my duplicate on a failed save, and take a 90ft fall, for 9d6 bludgeoning damage.
And that's assuming there's no chasm over which I can simply send my duplicate...
Invoke Duplicity allows you to cast spells as if you were in the duplicate's space, but it doesn't change anything else about the spell. A strict reading of the text of Switcheroo might suggest that because it says you and the target switch places, the target's going to end up where you are, not where the duplicate is. I think you could argue it either way.
pronouns: he/she/they
The exact wording of the spell is "instantly teleport to your space".
Isn't this precisely what the Invoke Duplicity: Cast Spells changes? Making it so that, as far as casting spells is concerned, "my space" is the illusion's space.
Also, as I'm thinking about this way of reading it, claiming that you and your location or your space are distinct readings and it can be used to deny some interactions with spells that use the player's location, I'm not sure this particularly conservative interpretation changes anything.
Because I could use that same conservative interpretation to say that Invoke Duplicity: Cast Spells says I cast spells as though me, the actual PC, were in the illusion's space, not that our spaces are swapped. And so even though the spells says me and the target switch places (which it actually doesn't, but some spells like Command: Approach actually word it this way), it should still consider the illusion for any effect involving the player's location.
Because if you don't, that means you're using 2 distinct definitions for the word "you" in the spell's description and the word "you" in Invoke Duplicity: Cast Spells. And I can't think of any justification for doing that.
The way I understand Invoke Duplicity (or Gaze of Two Minds, since it's similar), you cast from the illusion's space, but your actual position remains the same for the proposed interaction.
EDIT: this thread could help in the debate, where the real space/position changes the outcome: Gaze of Two Minds 2024 -- multiple senses at once?
I disagree. What you say is true, but it doesn't change much. "as though" means "it's not, but you pretend it is". That's quite literally the meaning of "as though". When you have something that says "as though", the actual state of things doesn't matter. You treat things "as though" they were in the proposed way.
And that's how I read Switcheroo. I cast it as though I was in my duplicate's space. So when it comes to resolve where the enemy goes, it goes where I would have been, that is to say the illusion's space. There is no reason to believe that casting from the illusion's space would have no consequences on the spells being cast. I think that's adding an arbitrary limitation.
Oh, but I'm realizing something... It's only the locations that are swapped, not the actual being. If I was in the illusion's space, it would still be me who would end up in the enemy's place, and not my illusion. That being said, my plan would still work, because the important part would be to send the enemy where my illusion is, and if I'm considered in the illusion's space as I'm casting the spell, then that's exactly what should happen.
It's just that my illusion would stay where it is (wouldn't be an issue since the illusion doesn't occupy its space), and it would be me who would end up where the enemy previously was. Plus, after level 6, I can always use my bonus action to swap places with my illusion anyway.
Both readings seem equally valid depending on how you interpret the Cast Spells ability.
1: The illusion serves as a full replacement for you in the spell
2: The illusion serves as the point of origin of the spell, largely impacting the range of the spellcasting
So... There's already issues with that ability. For instance:
-Gust of Wind and Misty Step are both Self spells
-If point 1 is correct, then Gust of Wind can be centered on the illusion, but you can't teleport with Misty Step while using that ability, only the illusion can
-If point 2 is correct, then you can teleport within 30 feet of your illusion with Misty Step, but casting Gust of Wind from the illusion's position still centers it on you
Ask your DM how it'll work and be consistent, I guess. Can't have it both ways.
Basically: Either you can use the ability to cast Misty Step or you can use Switcheroo to swap a person with the illusion. Can't do both, that comes into a rules conflict.
I don't think your reading #1 can be argued. Invoke Duplicity makes it quite clear that you are still casting the spell, but you do so from the illusion's position. It's not your illusion casting the spell.
It might be easier to picture it by simply pretending that the player actually is in the illusion's space (which by the way is what the description says we should do anyway), and wonder what would happen then.
Misty Step: you teleport where you want to go, making no difference with using it normally.
Gust of wind: the gust originates from where the illusion is.
Switcheroo: the enemy is teleported where your illusion is, you are teleported where the enemy was, and your illusion is still in the same place.
I cannot read the spell, but the Invoke Duplicity question is interesting in its own right..
And I read it as the spell's origin point is the illusion's space, with all that entails, so you can misty step up to 30 feet from its location, no matter where you are in relation.
The question for Switcheroo would depends on whether the spell's origin point matters for anything but range. The likely answers seem to be:
Without the actual text, I can only speculate, but 1 and 3 seem most in line with the spirit of the ability.
(And frankly, the Misty Step trick is much more interesting than the Switcheroo one, which you don't need the duplicate to do in the first place, since you can fly. )
The relevant part of the spell description is:
The target must succeed on a Charisma saving throw or instantly teleport to your space whilst you teleport to the one it previously occupied.
pronouns: he/she/they
Gust of Wind would originate from where you are according to your examples, not from the illusion. That's the thing.
It doesn't matter what the point of origin was. It matters where you are. That's what I'm saying: The reading that lets you use Misty Step from the illusion's space also stops you from using Gust of Wind from its space. The reading that lets you use Gust of Wind from the illusion's space stops you from using Misty Step from the illusion's space because that treats the illusion as you for the purposes of the spell, so the illusion teleports instead.
I understand what you're trying to say. But I don't think it works that way, because in order to interpret it the way you are, you would need to make a distinction between "you" and "your location" for the context of the spell, without making it in the context of Invoke Duplicity. You'd need to read these 2 descriptions with different interpretations of the word "you", which would be inconsistent. That's why I think it makes no difference.
If you're saying "oh no, it uses your actual location because the spell says "you" in its wording", then you're saying that this wording matters in the spell description, but not in Invoke Duplicity's description. That makes no sense. If you're gonna make that distinction, you need to make it everywhere, including in Invoke Duplicity's description, and in the end it changes nothing.
Because when you say "it originates from you", you're supposed to be reading that in a context where you're already assuming that "you" is located in the illusion's space.
So when you read Gust of Wind,
in that context, as you read that line, that "you" is assumed to be located where your illusion is.
And when you read Misty Step,
these "you" are again assumed to be located where your illusion is. But it's still you who are going to be teleported, because no matter where you are located, "you" is still "you". So no, it wouldn't teleport your illusion. It's not a "complete replacement" as you suggest, you're simply assuming that you, the player, are located where your illusion is.
Again, if you're gonna make that "you" and "your location" distinction, you also have to make it when reading Invoke Duplicity.
so the highlighted "you" in this reading should also be read as "you", the player. And I'm not highlighting the others because only the highlighted one is concerned by "as though". You're supposed to use your imagination for a moment and assume that you are not where you are, but where your illusion is instead.
I agree with this.
Also, I think Invoke Duplicity should work with "Range: Self" spells to be advantageous for the cleric. This is my opinion from a different thread:
Sorry, I didn't see your reply before.
I agree with you on your interpretation of Invoke Duplicity and its interaction with Misty Step and Gust of Wind.
So maybe I'm just splitting hairs regarding Switcheroo, and I could also agree with your way of ruling it.
The "you" in the spell is still you. For instance, if you cast Mirror Image, it's not the duplicate that gets the images. Some spells just don't work as well as others with this ability, and that's something you have to face. While you're casting as if from that space, there's a difference between casting a spell and resolving spell effects. The casting lets it originate from that spot, but that's as far as it goes.
Essentially: "You" are still you. The position only matters for where you're casting from, for the sake of spell range and origin point. Back to my Gust of Wind example, the wind would still originate from you for the same reason that Mirror Image still applies to you.
I already made the "you" is still "you" point in my own reply, and while I agree with the way you're reading Mirror Image, I still disagree with the way you read Gust of Wind.
But I can understand why you see it this way. You're assuming that this transposition would only last for the moment that the spell is cast, but wouldn't last for the concentration period.
And that would be a valid reading, were it not for the pre-release video that TarodNet mentioned, which indicates that the assumption of transposition should be kept while concentrating on a spell you cast this way:
But I'll agree that at this point, it's no longer RAW. Because the way Invoke Duplicity worded, it's unclear whether the assumption of transposition is kept during the concentration, and as a DM, you can choose to interpret it either way, pre-release video or not.
But if you rule it that way, most spells won't work with Invoke Duplicity or Gaze of Two Minds:
- Fireball: "A bright streak flashes from you..."
- Eldritch Blast: "You hurl a beam of crackling energy"
And all the "Self: Range" spells would be useless, when that kind of range means:
So, when using your Duplicity, the spell is cast as if the Duplicity were the caster. The same should apply to "Range: Touch" or when using a Distance.
This is how I'm ruling it, at least.
I think it's one of these cases where a strict RAW ruling would break the intent of the feature in a way that is just too obvious to ignore.
I remember a while ago, shortly after I joined this forum, I tried to make a case that Stone Shape could be used to create an object in absolutely any dimension, because the way it's worded, the "5ft cube" dimension limitation is only explicitly stated to apply to the stone you're shaping in its initial state, but there's no mention of a limit for the dimensions of the object that you're shaping the stone into, so you'd be able to take a 5ft cube of stone and reshape it into a 20ft long bridge, for example. It took a tweet from one of the designers to shut me up on that issue, confirming that the spell was not intended to be used in such a way.
I think it's the same thing here. If you read it as pedantically as possible, concentration spells can only be cast from the point of view of the illusion during the spellcasting time, but after that, it would come back to your actual self while you concentrate on it... But it just looks too absurd to be how the feature is intended to work.
The video talks about concentration only because the cleric is now able to use concentration spells (such as the updated Spiritual Weapon) alongside the duplicate now. It says nothing about any interaction between concentration spells and the duplicate beyond the fact that you can use both now.
But it's clear you're intent on reading this in whatever way benefits you most on a spell-to-spell basis, so I have no reason to continue.
I'm not projecting intent onto you, so don't project intent onto me. That's just rude. But just imagine it happen, it would obviously look nonsensical. You can't say "oh you're just biased" simply because you won't make that effort.
Plus, I don't really care about Gust of Wind. I never use that spell. My initial question was about Switcheroo, which is not a concentration spell, and we've already agreed it should indeed teleport the enemy where the illusion is. I don't have any stakes in the rest of this discussion, but even if I had, it wouldn't be my first time admitting that I can't do what I projected to do.
In which case, the RAW reading is:
Target ends up in the duplicate's space, you end up in the target's.
You remain you for the purposes of the teleport, but your location is considered to be that of the duplicate.
That said, I wouldn't judge a GM who decided that was too weird, and still had the target swap with the player, or even the duplicate.
The tactic that started this thread works, since it appears the designers of the spell didn't include a protective clause like there is in Vortex Warp (I wonder if they included something to prevent swapping huge creatures into a space that won't hold them?)