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The wording of Shield of Faith suggests that it can be used to reveal a known but invisible enemy:

A shimmering field appears and surrounds a creature of your choice within range (60 feet), granting it a +2 bonus to AC for the duration.

Unlike many spells, there's no requirement for the caster to see the target.

A Jeremy Crawford citation indicates that there needs to be a clear path from the caster to the target.

A fairly common "boss fight" scenario is that the heroes enter the boss' lair, the boss delivers an ominous speech, everyone rolls initiative, and on the boss' first move they cast Invisibility (or Greater Invisibility). Would casting "Shield of Faith" on the boss be a cheap counter? (The boss getting an AC boost, of course, is just hilarious).

Akixkisu
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andrewtinka
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2 Answers2

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It should work, but may not be as much of a counter as you think

With the description of the spell as written, you should be able to cast it on a hostile, invisible target - so long as it is within range and you have a clear path, as you say.

However, keep in mind that 'spells do (only) what they say they do'. Just because the target is surrounded by a 'shimmering field' doesn't mean that their invisibility is negated. Compare the description from Shield of Faith with that from Faerie Fire. The latter spell also outlines the target with light, but explicitly says "the affected creature or object can’t benefit from being invisible." Since Shield of Faith does not say that, there is no reason to think that invisibility would be countered.

In particular, the invisible-and-now-shielded boss would certainly still receive the benefits of advantage on attacks on creatures that could not see it, and of being attacked at disadvantage because it could not be seen, as standard per the Invisible condition.

How noticeable the 'shimmering field' is would be open to DM interpretation - would it blur their edges when they were visible but be an almost unnoticeable distortion in the air when invisible during the heat of combat? Or would it amount to a glowing outline like faerie fire - obvious but not shedding light?

A generous GM might allow you to use the shimmering field when deciding 'what space to attack' when calling attacks on unseen opponents, and might adjust attempts for the shielded creature to Hide (adjusting their Stealth roll or their opponents' Perception rolls). But none of these allowances should be taken as given from the description in the spell itself, simply because it doesn't actually say that it does that.

Kirt
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  • Or advantage on perception checks or disadvantage on stealth – Yakk Dec 28 '20 at 15:45
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    "would it blur their edges when visible but be an almost unnoticeable distortion when invisible during the heat of combat?" I'm picturing a shimmering in the air like the shimmering of hot air, or the outline of the Predator from them movie of the same name. – nick012000 Dec 28 '20 at 15:54
  • @nick012000 I was actually thinking the same thing but didn't know if that was too dated a reference. – Kirt Dec 28 '20 at 17:36
  • It's important, I think, that Invisible is an explicit condition. (I keep forgetting that because it's the only "good" condition...) – andrewtinka Dec 28 '20 at 19:29
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    The Invisible condition says "The creature's location can be detected by any noise it makes or any tracks it leaves." I think even not-so-generous GMs should let you locate an enemy by the shimmering field that surrounds it; but this is just quibbling over strictness. – andrewtinka Dec 28 '20 at 19:39
  • @andrewtinka Yes, a creature that is invisible but not (successfully) Hidden can be detected by sound or tracks. The question is whether the shimmering field makes that detection any more likely. Since that is not an explicit feature of Shield of Faith, a DM would be being generous in allowing the Shield to affect the chance of detection. – Kirt Dec 28 '20 at 20:43
  • I agree with @andrewtinka. The shimmering field occupies the same square as the invisible creature, making it trivial to identify where it is located. – Guillaume F. May 12 '22 at 09:08
  • @GuillaumeF.: If you're talking about the "shimmer" of heat over a hot road, that's not super obvious if you haven't already located the target. Disadvantage on Stealth checks? Sure, they're invisible, but they no longer have advantage to Hide. But if you lose track of them (because they successfully hid), locating them again could be tricky in open areas, poorly lit areas, etc. – ShadowRanger Jan 26 '23 at 20:01
  • @ShadowRanger Being invisible means you can Hide even when others have LoS on you, in plain sight. But invisibility does not grant advantage to Stealth rolls – Kirt Jan 27 '23 at 15:49
  • @Kirt: True. I suppose I'd rule it as they have Disadvantage on the Stealth check, but they're still sufficiently obscured by the invisibility that observers continue to have the normal disadvantage for their Perception. So, practically speaking, it would mostly cancel out (Disadvantaged Stealth vs. Disadvantaged Perception), which doesn't seem unreasonable. – ShadowRanger Jan 27 '23 at 16:11
  • @Kirt: I've been reading a lot of stuff related to Stealth lately, and I'm coming to the conclusion that, without necessarily intending to or spelling it out, there are really two separate modifiers involved, one for being seen, one for being heard. If you make yourself hard to see, the observer has disadvantage on Perception (but you don't get advantage on Stealth), if you're hard to hear, you get advantage on Stealth, but they roll Perception normally. Only exception to this I've seen is Cloak of Elvenkind (which imposes disadvantage on them and grants advantage to you). – ShadowRanger Jan 27 '23 at 16:14
  • @ShadowRanger It is certainly complicated, and possibly counter-intuitive. – Kirt Jan 27 '23 at 16:15
  • And I just treat the Cloak of Elvenkind as implicitly reducing your sound to some extent (it makes no sense that being actually invisible is somehow less effective than being clad in clothing that merely camouflages you, and I say this as someone playing an Arcane Trickster who has that Cloak; I'm in some ways better than invisible, because of the combined advantage/disadvantage, and the fact that Truesight has no special ability to detect me, where it would see right through invisibility). – ShadowRanger Jan 27 '23 at 16:16
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No, it doesn't negate the effect of invisibility

Spells only do what they say they do. Shield of faith doesn't say anything about countering invisibility, unlike other spells such as faerie fire. Arguably it could show the current location of the target creature when the spell is cast. However, it doesn't say the shimmering field remains afterwards so you'd be effectively fighting blind.

V2Blast
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Allan Mills
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  • Parsing the grammar of the description, it seems to me that it is the field that grants the AC bonus, and the AC bonus lasts for the duration of the spell. Thus it is at least implied that the field itself lasts for the duration of the spell, not that it appears as an effect of the casting and then goes away. – Kirt Dec 28 '20 at 02:33