Can it walk through walls or operate doors?

An important question from belfastbiker. "Can it walk through walls or operate doors?" 

It is illusory, typically meaning non-physical but not specified in the spell... If it makes a corporeal copy of the character that would be incredibly powerful, even in comparison to it being incorporeal and allowing it to pass through solid objects while you use its senses and speak through it. In the very least, I would say you have to pick one or the other. (I say its entierely incorporeal and that it CAN move beyond objects but only if the caster -using their own or the double's eyes- can see the end location)

This spell should get run through the errata mill for clarity. I have MANY questions. 

What is the range that the double can be from the source?

dfmjr, with no limit in the spell the answer is that you can be anywhere, even on other planes ... You can cast Mislead in one of the Nine Hells and then cast Plane shift and use the double as your body in Hell while you are relaxing in the Prime Material plane. 

Quote from belfastbiker >>

Can it walk through walls or operate doors?

I would say the spell cannot walk through walls because there is nothing in the spell that says it can. And I would say the illusion is intangible because other illusion spells are intangible unless they say otherwise.

The duplicate originates in your space and can move at twice your movement speed in a round. The spell has a max duration of 1 hour.

Assuming a speed of 30ft per round it can get ((30x2)×600) = 36,000ft (6.8 miles) away over the course of the spell.

It's unbelievable as a scouting spell while keeping your squishy caster body safely hidden away.

If you had a wizard or Bard friend cast this into a ring of spell storing, as a sorcerer you could pull off a "Loki" and nobody'd even see the casting of it with subtle spell meta-magic.

Due to spell level, I think it would make sense to apply major image rules to the double.

Quote from jpalger >>

Due to spell level, I think it would make sense to apply major image rules to the double.

This is what I would default to also - I dont think any players would balk at the rules listed there being the default. 

"As long as you are within range of the illusion, you can use your action to cause the image to move to any other spot within range. As the image changes location, you can alter its appearance so that its movements appear natural for the image. For example, if you create an image of a creature and move it, you can alter the image so that it appears to be walking. Similarly, you can cause the illusion to make different sounds at different times, even making it carry on a conversation, for example. 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, and its other sensory qualities become faint to the creature."

I specifically would not apply major image rules.  This spell is two levels higher, and very clearly doesn't included the restrictions lower level illusion spells have.  So characters cannot use an action for an Investigation check to determine it isn't real.  It also should hold up to physical inspection.  (Two restrictions pointedly applied to other illusions).

The spell text doesn't give it any Actions it can take, like a "Attack" or"Help" or "Use an object" option.  So I'd rule no on opening doors or any sort of environmental manipulation.  But I think both a RAW and RAI interpretation would mean this should be a very convincing, hard to discern duplicate of the caster.  

Like the Loki trick alluded to above; it's so good it fools even Odin and others that should know better.

Quote from travisfisher13 >>

I specifically would not apply major image rules.  This spell is two levels higher, and very clearly doesn't included the restrictions lower level illusion spells have. ------ It also should hold up to physical inspection ------ The spell text doesn't give it any Actions ------ So I'd rule no on opening doors or any sort of environmental manipulation. 

While I could agree to the notion of a very high level illusion not having the lower level spell restrictions I feel the need to point out the two suggestions afterwards; these two things are mutually exclusive to my understanding.

If you cannot physically disprove the illusion, that means it interacts and reacts to environmental stimuli and that those environments react to it. If you can disprove it, that means it fails to affect or be affected by the environment. It is described as being able to a gesture, speak, and behave in whatever way the caster chooses, so I would imagine the illusion could mime the action of catching an object or pulling a lever, it is just a matter of if they can physically interact. 

Can it grab the key in a door and open it without its hand passing through? If no, then physical inspection by way of a handshake would reveal the illusion. 

If the illusion has a physical presence and can catch the copper coin I threw to it (thereby disproving it was a lower level illusion), then clearly it can pick up, carry, drop items to manipulate the environment and should be able to put a key in a door and turn it. 

I shoot the illusion with my crossbow; the arrow passes through it and hits the wall behind - I see it is illusory, OR, the arrow is stopped as it sticks into it - it can affect physical objects in the environment. 

If after all this we decide the environment passes through the Illusion, then we can summarise the illusion can also pass through the environment in the same fashion. Walking through the slotted bars of a prison cell out into the guardhouse proper for example - and if it impossible to discern that the thing passing through bars is illusory even by it failing to preserve the concept of physical interaction with the environment, then the mage-guard would get no check to discern its illusory nature must assume that it was the actual caster  even after such an impossible act and those mage guard knowing full well of the concept of an illusion. 

This spell still needs clarification. 

Obviously this spell needs a lot of clarification, or it leaves a lot up to the DM...

But what is the duration of the invisibility? It does not specifically state, it only says;

“The double lasts for the duration, but the invisibility ends if you attack or cast a spell.”
This makes it sound like the invisibility has infinite duration unless you attack or cast a spell, although I assume that it adheres to the duration of 1 hour stated in the spell parameters. 1 hour invisibility is still good though. Let’s you snoop through that nobles house while your double smiles and nods at his inane stories.

Now with the new twilight domain, you can be slightly less squishy while still being able to cast this spell.

Well by that logic, the invisibility in the spell 'invisibility' would also last that long. I am pretty sure that all the spell's effects end after the concentration ends.

If I am reading the spell correctly, you use your action to cast the spell, your body turns invisible, and a illusory duplicate appears in your place, but you have to wait until your next turn (or use another action if you action surge) to move it. If that's the case this doesn't help much during combat if the goal is to deceive an enemy into chasing your duplicate.

Also, if you did use it that way and a creature was in melee range of you, as the duplicate left, and took an opportunity attack, would it hit you or the duplicate? Would there need to be a roll involved? I'm not sure if it was meant to be used directly in combat or not.

Quote from belfastbiker >>

Can it walk through walls or operate doors?

 "Walk through walls, disappear, and fly!"

Does bring up a matter, does it only get to move twice your WALK speed, or any speeds that you have? If you, somehow, have a fly speed when you cast this, then can the copy fly also, up to twice it?

I feel like this fits the trickery domain better than twilight. Thoughts? 

Can it walk through walls, disappear, or fly? Is it much more unique than the other guy?

"You become invisible at the same time that an illusory double of you appears where you are standing."

Since becoming invisible does not make you intangible, then the illusion must be intangible if appears where you are standing. That would indicate that the illusion could walk through walls but could not operate a door. Passing through walls could reveal the illusion for what it is though.

"make it gesture, speak, and behave in whatever way you choose."

The natural assumption here is that behave refers to its actions but could it not also apply to its physical appearance? For example, to have a greenish tint or to become translucent?

So I think it would be acceptable to have the illusion go up to a wall, perform several gestures as if it was casting a spell and then become somewhat translucent and then pass through the wall.

Quote from AshtonSurespell >>

I feel like this fits the trickery domain better than twilight. Thoughts? 

 I totally agree with this except the Trickery Domain's Channel Divinity: Invoke Duplicity basically does a slightly different version of this spell. You don't turn invisible and you can't see through the duplicate's senses, but you can cast spells through the duplicate. And RAW both are concentration so you couldn't have both active for double duplicates. I say RAW because I've almost always homebrewed it as non-conc. (for my players as a DM and asked my DM to make the change when I'm a player).