Invoke Duplicity + Armor of Agathys

[Giant2005]

Could you cast AoA on yourself as if you were in the space of your illusory self, in order to have a target damaged whenever it attacks the illusion, without the AoA actually being damaged itself?

[Arkhios]

Can the Illusory duplicate be attacked? If so, I suppose it could work.

[djreynolds]

Are you saying the adversary thinks your illusionary self has up AoA and acts accordingly?

So a trickster cleric/warlock casts this AoA on his illusionary self... I think it would work but the AoA would be on the illusion and it would degrade as it was hit

[Lombra]

I don't think that you can cast this kind of spells on illusions. You can cast it as if you are in the space of the illusion but the target can't be the illusion.

[Dalebert]

I don't think that you can cast this kind of spells on illusions. You can cast it as if you are in the space of the illusion but the target can't be the illusion.

I'm thinking the same thing. Spells can originate from the illusion but I don't see how that allows you to pick a target that's different than what the spell allows. So it would make no sense to cast a spell with a range of "self" from the illusion. Those spells can only affect you. It would just fizzle if you tried that.

[Giant2005]

I'm thinking the same thing. Spells can originate from the illusion but I don't see how that allows you to pick a target that's different than what the spell allows. So it would make no sense to cast a spell with a range of "self" from the illusion. Those spells can only affect you. It would just fizzle if you tried that.

You aren't casting the spell on the illusion, you are casting it on yourself as if you were standing right where the illusion is. So any attacks that target the illusion are targeting you as if you were standing in its place, for all purposes but damage.

[Vaz]

No, because you are not targeting the space, and indeed cannot, because it is range self, which it defines as yourself.

[Joe the Rat]

On a related thought, could you hellish rebuke someone that attacked your duplicate?

[Dalebert]

On a related thought, could you hellish rebuke someone that attacked your duplicate?

The ability allows spells to originate from the duplicate. That's all. It doesn't allow you to change the way a spell works. Hellish Rebuke requires a creature to attack you before you can do it; not something else. You could, however, have the fire originate from the duplicate. The coolest thing about having a spell come from the duplicate is it takes attention off of you and makes it more believable that it's more than just an illusion. Besides that, it's a handy way to extend the range of your spells or reach someone for healing that is in a not-safe place for you to go.

[Giant2005]

The ability allows spells to originate from the duplicate. That's all. It doesn't allow you to change the way a spell works. Hellish Rebuke requires a creature to attack you before you can do it; not something else.

Spells don't just originate from the duplicate: "For the duration, you can cast spells as though you were in the illusion’s space".
If you were in the illusion's space, Hellish Rebuke would obviously work fine, ergo if you are casting Hellish Rebuke as if you were in the illusion's space, it should work fine too.

[Vaz]

Yes, but that is casting the spell, you still aren't being attacked, the duplicate is. Casting it while in his space has no additional effect, as it only triggers when you are attacked.b

[Giant2005]

Yes, but that is casting the spell, you still aren't being attacked, the duplicate is. Casting it while in his space has no additional effect, as it only triggers when you are attacked.b

But if you were in that space, you would be attacked. So if you are casting it as if you were in that space, you are casting it as if you were attacked.

[Dalebert]

I see where you're coming from and maybe you can convince a DM of that and if you can, go for it. It's definitely a reach. You can't cast the spell until after you're attacked. It's not "something attacks something in a space you occupy". The illusion is not you. Something attacking it is not attacking you regardless of whether you (sort of) share it's space.

If someone attacks a swarm that shares your space, can you Hellish Rebuke them?

[Joe the Rat]

Having invoked the idea (ha! Warlock humor), I think I see where it falls apart:

Casting Time: 1 reaction, which you take in response to being damaged by a creature within 60 feet of you that you can see
AoA has the same issue - there's no damage being done to activate the effect.

[Tanarii]

But if you were in that space, you would be attacked. So if you are casting it as if you were in that space, you are casting it as if you were attacked.
That's poor logic. You cast it as if you were standing in the space. You don't get to treat it as if you were there for all purposes, including triggers.

[Dalebert]

That's poor logic. You cast it as if you were standing in the space. You don't get to treat it as if you were there for all purposes, including triggers.

Thank you. I was having a hard time expressing the same idea. The implication is the power virtually puts you in the space even before you start casting a spell which is absurd.

But Joe the Rat has shown why this doesn't work even disregarding that complication.

[Llama513]

Might I add, since it is unaffected by attacks or damage, even if you could put the spell on it, AoA would do literally nothing since it requires an attack to be successfully made which is not possible

[JellyPooga]

The spell you're looking for is Phantasmal Force, not Armour of Agathys. AoA targets "Self", so whether it originates from you or an illusory duplicate, it will only ever trigger whem you are attacked and damaged. Phantasmal Force on the other hand, will give your opponent the illusion that not only that there's an illusiory "you", but that they also have AoA active on that "you" (without ever having to cast, or even know AoA, incidentally).

[Giant2005]

That's poor logic. You cast it as if you were standing in the space. You don't get to treat it as if you were there for all purposes, including triggers.

It isn't poor logic - it is almost certainly the RAI of the ability whether or not we disagree on the RAW. The whole point of the ability is to make the illusion more convincing by having it cast your spells as if it were the genuine article. Sure the description specifies the location, but what is important about the location is the fact that your illusion is standing upon it - it is the illusion that is important, not the space it is occupying.

Either way, others have pointed out that the spell requires actual damage to function, so it wouldn't work anyway.