[RPG] nvoke Duplicity use touch spells

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.

The Cleric, needs to be in range for the spell to work, but you can cast counterspell if you see either of them casting a spell:

Counterspell has a casting time of:

1 reaction, which you take when you see a creature within 60 feet of you Casting a Spell

So you would think that you would need to be able to see a real creature casting a spell to have this work. However, Jeremy Crawford, 5e lead rules designer, responded on twitter to two questions about this topic on twitter.

Q1: Hi!! Quick q: Trickery cleric uses Invoke Duplicity to cast spells from. The illusory image that ID [sic] creates is then counterspelled in the process of casting a spell; does the counterspell stop the spell cast, or fail as it's an illusion?

A1: Invoke Duplicity doesn't protect a cleric from being counterspelled if the person casting counterspell can see the cleric/illusion and the cleric is within 60 feet of the caster.

source

and

Q2: Does seeing the illusion from Invoke Duplicity count as “seeing” the actual Cleric?

A2: Seeing the illusion created by Invoke Duplicity isn't the same as seeing >the cleric. However, seeing the illusion is sufficient for some things in the >game, like counterspell, that are triggered by seeing processes (seeing the >cleric casting a spell, for example).

source

Based on this ruling, if you can see either the illusion or the cleric themself in the process of casting a spell, you have a valid trigger for counterspell. This is even though the illusion isn't a creature. With that being said, Invoke Duplicity allows you to cast the spell as if you were in the illusion's space, but the Cleric is still the one casting the spell. Even if you react to the illusion appearing like it's casting a spell, the cleric needs to be in that 60 foot range for the counterspell to be successful, since they are the one who is going to be counterspelled.