How does the Trickery Domain cleric's Invoke Duplicity Channel Divinity option work?

Question

The Trickery Domain cleric gets the Channel Divinity: Invoke Duplicity feature at 2nd level, which creates "a perfect illusion of yourself" (PHB p.63).

However, CD:ID's description doesn't really tell us anything about what this illusory double actually does while it lasts (does it mimic its originator's actions, or does it act independently?), nor do the rules tell us whether this duplicate can be revealed to be an illusion -- using an Intelligence (Investigation) test, perhaps, or via a physical attack? -- and if it can be, what happens if someone "sees through it".

Have I missed something, or are the answers completely up to the DM? (I think the latter is perfectly fine, btw, just don't want to houserule something that's covered officially.)

Answer 1

The rules only cover combat (well..casting) actions for this ability and do not really speak to how to use this outside of a combat situation.

Here's what we do know about it:

• You can use it as a point of origin for casting (Though you still have to be able to see the effect point as it uses your senses, not the duplicate's)
• You get advantage if it's in melee with you.

The problem here is that it's a bit of an odd thing for it to not speak to whether or not it can be A. attacked and B. disbelieved.

As far as A goes, it should be able to be attacked, but obviously it's an illusion, so it's not going to take damage. The concern I'd have is a situation where you and the illusion are both valid targets, how does an opponent decide (as a DM, I'd flip a coin unless the monster has a good reason to know otherwise (like they saw you cast the spell just a moment ago).

The question of whether or not it can be disbelieved is far more complicated. The key word here seems to be "perfect," if it's a perfect illusion then it would seem that it would quite hard for it to be disbelieved. Perhaps if a monster had reason to disbelieve it (for instance, was interacting with it in some way), they could make a wisdom saving throw against your spell save DC possibly at disadvantage (it depends on how strongly you want to take the word "perfect").

Ultimately though, all we have to go on are those two bullet points above. So this is squarely in the land of DM discretion.

Answer 2

Invoke Duplicity does what it says, which is create a perfect illusion. Perfect, as in flawless, complete, cannot be improved upon. There is no mundane mean of detecting that it is an illusion. It includes all 5 senses. Yes, if you lick it, it would taste like cleric. It acts, and reacts, in a manner that perfectly duplicates the original (within the limitations of actions described, ie. it can't attack with a weapon). If there were limitations or a possibility of detection, the description would say so.

Answer 3

For the purposes of Invoke Duplicity, a perfect illusion creates a perfect duplicate of the caster.

As long as the cleric is present and maintaining concentration:

• The duplicate exists to enemies as a physical clone, but can only grant advantage to the cleric in melee. It can move and speak independently or simultaneously at the clerics' discretion.

• The dupe is intangible, as an illusion. It can't be used to manipulate objects. The effect doesn't last much longer than a minute, so the dupe will likely vanish before putting it through a Turing test.

• It acts and responds to damage and spells in a believable fashion if the cleric can see. As a false target, it takes no actual damage. It can stagger and react in pain to critical swings and empowered disintegrate alike, but always stays standing, as the cleric desires.

• It appears to pass saving throws it doesn't need to take.

• The duplicate is created in the clerics' space and either the dupe or the cleric can move, thus making them indiscernible even if the invocation is witnessed. Bonus theater points if both move away.

• The cleric must maintain sight/hearing proximity for it to do anything intelligent. If the caster is blinded/deafened, the dupe is still capable of moving, idling, and pretending to listen.

• It is [almost] impossible to hide spellcasting by the cleric when a dupe is employed as a lone decoy. Subtle Spell metamagic is required for the dupe to cast a spell while the cleric hides or appears to do nothing. This is unique to multiclassed cleric-sorcerers.

• Dispel Magic has no effect on the Dupe, as it is a divine effect, not a spell. Antimagic Field will suppress the dupe. True sight, or abilities that explicitly identify illusions (Eg, Investigative Rogue) are the only way one can identify which is the dupe.

• The Dupe cannot be used to cast spells that exclude targeting self to target the caster; eg. The cleric cannot use the Dupe to cast Life Transference on himself. Life Transference will have its normal effect on the cleric, even if the dupe is used as a proxy to heal a target that is not the cleric.

You can do some fun things with a multiclassed Cleric/Sorcerer with Twin spell or Subtle spell in combination with Invoke Duplicity. Cleric/Rogues are fearsome little cultists able to give themselves advantage in one of the more creepy/cool ways.

Answer 4

Mechanically I'd use this argument for Invoke Duplicity:

Requires Concentration.

Use a Bonus Action to move duplicate.

Spells may be cast through duplicate.

Duplicate cannot interact physically with objects or creatures.

Gain advantage to attack if in melee with duplicate.

If player rolls above a 11 on d20 duplicate is targeted. Cannot use this effect effect on AOE spells like fireball.

Duplicate has AC of 10+Dex modifier of player.

Duplicate has same HP as player. Duplicate may not be healed.

Duplicate cannot be dispelled.

Duplicate has no effect on creatures with blind sight or true sight.

Duplicate is lost if reduced to 0HP or player loses concentration.

Answer 5

Sorry but you all seem to be complicating things a little bit.

Most people tend to forget that outside of combat things have basically the same rules: you still have to wait your turn, if two people are trying to get something simultaneously you should role for initiative (the DM can decide it but, rolling it seems more fair) and of course magic has the same rules and effects in and out of combat.

So, it is what it is:

• It lasts 1 minute or if you lose concentration.
• It is a perfect copy so (once again, don't complicate it) there's no reason for some one to doubt it isn't the real thing unless that someone is already expecting you to pull something like this.
• to the fact that it doesn't talk, let's face it if someone you know (or not) doesn't reply when you talk to them your first thought is "this guy is rude or being a douche" it isn't properly "hey everybody this is a clone" when you get to that the spell has already ended!

Answer 6

I'd use the mirror image stats for the illusion:

Three illusory duplicates of yourself appear in your space. Until the spell ends, the duplicates move with you and mimic your actions, shifting position so it's impossible to track which image is real. You can use your action to dismiss the illusory duplicates.

Each time a creature targets you with an attack during the spell's duration, roll a d20 to determine whether the attack instead targets one of your duplicates.

If you have three duplicates, you must roll a 6 or higher to change the attack's target to a duplicate. With two duplicates, you must roll an 8 or higher. With one duplicate, you must roll an 11 or higher.

A duplicate's AC equals 10 + your Dexterity modifier. If an attack hits a duplicate, the duplicate is destroyed. A duplicate can be destroyed only by an attack that hits it. It ignores all other damage and effects. The spell ends when all three duplicates are destroyed.

A creature is unaffected by this spell if it can't see, if it relies on senses other than sight, such as blindsight, or if it can perceive illusions as false, as with truesight.