Imagine that you have cast True Polymorph to turn a medium object into a Helmed Horror with Spell Immunity to Antimagic Field. If you were to then True Polymorph that Helmed Horror into something else, it would lose its Spell Immunity, as its entire statblock is changed. However, what exactly would happen if the newly True Polymorphed creature walked into an Antimagic Field?

I see two plausible outcomes:

  1. Both layers of True Polymorph are suppressed simultaneously and the creature is immediately turned back into a medium object.
  2. The most recent layer of True Polymorph is suppressed, at which point the Helmed Horror's Spell Immunity kicks in and prevents the next layer from being suppressed.

I think each of these interpretations has a decent argument:

  1. This is how Dispel Magic works. If the Helmed Horror also had Spell Immunity to Dispel Magic, the underlying layer of True Polymorph could still be dispelled, because Dispel Magic reads (emphasis mine):

    For each spell of 4th level or higher on the target, make an ability check using your spellcasting ability. The DC equals 10 + the spell's level. On a successful check, the spell ends.

    Both layers of True Polymorph are on the target, and so both can be dispelled, and there is no reason to suspect they aren't dispelled simultaneously (before the Spell Immunity could ever kick in).

  2. Antimagic Field reads (emphasis mine):

    Any active spell or other magical effect on a creature or an object in the sphere is suppressed while the creature or object is in it.

    And while there are two layers of True Polymorph on the creature, it seems reasonable to assume that only the most recent is "active", due to the rules for Combining Magical Effects:

    The effects of the same spell cast multiple times don't combine, however. Instead, the most potent effect--such as the highest bonus--from those castings applies while their durations overlap, or the most recent effect applies if the castings are equally potent and their durations overlap.

    This (plausibly, I think) could be interpreted to mean that the most recent layer of True Polymorph is suppressed first, at which point Antimagic Field would suppress the next layer if not for the Spell Immunity.

Is one of these two interpretations unambiguously supported by Rules as Written?

  • 2
    \$\begingroup\$ I know Helmed Horror can be immune to any spells in theory, but I've never considered one immune to antimagic field! So maybe a prior question is "does this even work in the rules without causing a paradox?" \$\endgroup\$
    – PJRZ
    Commented Oct 10, 2019 at 16:17
  • \$\begingroup\$ Slightly related (stating that at least wish can override an antimagic field): "Can Wish Negate Antimagic Field?" \$\endgroup\$ Commented Oct 10, 2019 at 17:01
  • \$\begingroup\$ Can you even have True Polymorph in effect twice? Or does the second casting replace the first? \$\endgroup\$
    – Journer
    Commented Oct 10, 2019 at 19:58
  • \$\begingroup\$ @Journer The durations overlap, with the most recent taking effect. \$\endgroup\$
    – Cacse
    Commented Oct 10, 2019 at 20:40
  • \$\begingroup\$ It is worth considering if polymorphing into a helmed horror is the same as constructing one, otherwise you don't get to choose the spells it is immune too. \$\endgroup\$
    – John
    Commented Oct 11, 2019 at 12:12

4 Answers 4


Your assumption stated at the end is correct.

Your second possible interpretation mentions the following:

The most recent layer of True Polymorph is suppressed first, at which point Antimagic Field would suppress the next layer if not for the Spell Immunity.

Once the Helmed Horror is True Polymorphed into another creature, it no longer has Spell Immunity. Its stat block is replaced by that of its new form, and I'm assuming its new form doesn't also have Spell Immunity.

If the True Polymorph is ended on this form and it morphs back into a Helmed Horror, then the Spell Immunity would now be present, and this magical effect is immune to the antimagic field's effect because of the specificity.

The introduction to the game states:

Remember this: If a specific rule contradicts a general rule, the specific rule wins.

Antimagic field has a general effect of "everything in this range", while Helmed Horror's Spell Immunity specifies "ignore this particular thing".

The rule about combination you state means that you have two distinct True Polymorphs. They are not considered one effect, and each is separately active. This is more important for effects that confer a buff. Something currently affected by Shield of Faith to get +2 AC wouldn't benefit from a second casting.

  • \$\begingroup\$ So to be clear, do you think the creature would revert to a Helmed Horror but then continue to function in the Antimagic Field as a Helmed Horror? That's the implication of the assumption in question, but your deleted comments seemed to support the opposite position. \$\endgroup\$
    – Cacse
    Commented Oct 11, 2019 at 17:45
  • \$\begingroup\$ @Cacse My answer identifies my stance on the issue, and I believe it would revert to a Helmed Horror and continue to function as one. \$\endgroup\$
    – JRodge01
    Commented Oct 11, 2019 at 18:28
  • \$\begingroup\$ My mistake, I must have gotten the wrong impression from one of your deleted comments. \$\endgroup\$
    – Cacse
    Commented Oct 11, 2019 at 18:53
  • 2
    \$\begingroup\$ I don't think that's what "specific vs general" is really meant to mean. It's referring to the rules working from more broad (like general rules for actions per turn), with specific things sometimes acting as exceptions. It's not meant as a tool to weigh the strength of unrelated rules or powers which happen to interact. \$\endgroup\$
    – mattdm
    Commented Oct 12, 2019 at 3:22
  • \$\begingroup\$ @mattdm I think JRodge01 is correct in this case. See this related question for how specific vs general applies to spells and spell immunity. \$\endgroup\$
    – Cacse
    Commented Oct 13, 2019 at 17:27

It depends on how you conceptualize "active spells" because the rules don't have an explicit answer

The antimagic field spell states:

[...] Any active spell or other magical effect on a creature or an object in the sphere is suppressed while the creature or object is in it [...]

Here we default to the standard English meaning of "active" (from lexico):

  1. (of a thing) working; operative.

We so know from the section on overlapping effects that:

The effects of the same spell cast multiple times don't combine, however. Instead, the most potent effect [...] from those castings applies while their durations overlap [...]

There are two options:

  1. You believe that this makes one spell active and the other inactive:

    Thus, antimagic field removes the active one, and then the Helmed Horror's immunity would prevent it from removing the other.

  2. You believe that both castings are active:

    Thus, antimagic field would remove both at once (the spell never states that it goes one-by-one, it simply suppresses all active spells). This means the Helmed Horror's immunity would never kick in.

Argument in defense of 1.

The existence of "active spells" implies the existence of "inactive spells". Similarly, and suppressed spells are inactive, otherwise, (if we assume suppressed spells are still active) antimagic field would suppress a spell, and then suppress it again (because it's still active), and again, infinitely.

The question is then whether multiple castings of a spell causes one to be suppressed. It's kinda of a mess but post-errata the rules include the following regarding overlapping effects:

[...] only the effects of one of them—the most potent one—apply [...]

And so one of the spells is not currently doing anything, thus it is effectively suppressed and therefore inactive. This means that antimagic field would remove the castings of true polymorph one-by-one.

Argument in defense of 2.

An antimagic field does infinitely suppress a spell (as it never becomes inactive). This doesn't cause any problems, it's simply something unintuitive.

Alternatively, overlapping spells do not result in one being suppressed or inactive,; the spell is still there and it is still trying to do things. Though this is also true when antimagic field applies, the antimagic field spell explicitly suppresses spells whereas overlapping spells do not.

Thus there is no suppression when spells overlap, and as a result, both spells are active and are cancelled out by antimagic field simultaneously.

  • \$\begingroup\$ The querent is asking if there is an unambiguously correct answer from the rules as written. You should explicitly state that there is not, somewhere in your answer. \$\endgroup\$ Commented Oct 11, 2019 at 17:14
  • \$\begingroup\$ @thedarkwanderer Hopefully I've now done so. But I do believe user BenBarden's answer to be correct \$\endgroup\$ Commented Oct 11, 2019 at 17:27
  • \$\begingroup\$ I think the two arguments you've given in defense of the two positions are both reasonable. Perhaps there is no explicit RAW answer, but I'm going to continue to dig into some of the other answers and related questions to see if the use of the word "active" sheds some light on the issue before I choose a most helpful answer. \$\endgroup\$
    – Cacse
    Commented Oct 12, 2019 at 2:16

The Helmed Horror's Magic Immunity doesn't apply here.

The Helmed Horror has immunity to creator's choice of three spells. Antimagic field is a spell. Thus, it could be declared immune to that spell, and antimagic field (target: self) would have no effect if cast upon it directly (as it could not be caused to have an aura of antimagic field). Antimagic field also would not be able to target it. A summoned Helmed Horror with that immunity wouldn't be caused to wink out, for example.

However, that does not prevent it from targeting or stripping away the polymorph effect. Antimagic Field targets the effect directly, and the effect has no such protection. Note that there is a difference here between how Antimagic Field handles things and how Dispel Magic handles things. Generally, when trying to remove personal buffs, you cast Dispel Magic on the individual - something that Spell Immunity (Dispel Magic) would annul. Antimagic Field is an effect on all magical effects in the area, regardless of what they apply to.

As such, Antimagic Field would (temporarily) remove both polymorph effects.

  • \$\begingroup\$ I think this is a case of specific vs general. Normally Antimagic Field would suppress magic effects on a creature, but the spell immunity should prevent the creature from being affected, in the same way that a Rakshasa's immunity prevents its spell buffs from being dispelled. \$\endgroup\$
    – Cacse
    Commented Oct 11, 2019 at 17:43
  • \$\begingroup\$ @Cacse Look at the accepted answer there again. It's true for Dispel Magic, because Dispel Magic in that example targets the Rakshasa. It's not that its spell buffs cannot be dispelled by their own merits, it's that you cannot target them through the immune Rakshasa. Antimagic Field disrupts the effects directly, however, without targeting of that form. \$\endgroup\$
    – Ben Barden
    Commented Oct 11, 2019 at 17:58
  • \$\begingroup\$ @Cacse I have modified the text of the answer to address your argument. \$\endgroup\$
    – Ben Barden
    Commented Oct 11, 2019 at 18:11
  • 2
    \$\begingroup\$ "It's not that its spell buffs cannot be dispelled by their own merits, it's that you cannot target them through the immune Rakshasa." I think this is incorrect. As per the linked answer, even on a creature that isn't spell immune, you would still need to target the creature, not any "Haste effect" on it. And since the Rakshasa in question is immune to Dispel Magic, Dispel Magic has no effect on it and does not dispel Haste. I'm not sure how that case is different from this one: the Rakshasa's Haste is not dispelled, and it seems the Helmed Horror's True Polymorph would not be suppressed. \$\endgroup\$
    – Cacse
    Commented Oct 11, 2019 at 19:14
  • 1
    \$\begingroup\$ Immunity doesn't have any defined rules meaning. Do you mean to be arguing that the natural language use of 'immune to antimagic field' doesn't exclude one's spells from being affected? \$\endgroup\$ Commented Oct 11, 2019 at 19:46

Yes, everything is suppressed all at once.

The spell says:

Spells and other magical effects, except those created by an artifact or a deity, are suppressed in the sphere and can’t protrude into it.

As it is worded. An antimagic field suppresses any and all effects the second it overlaps their space.

A spell's "active" status and it having an active effect are two different things. The PHB/SRD's section on Casting a Spell states the following under the duration subheading:

Some spells require you to maintain concentration in order to keep their magic active.

Concentration spells lose their active status when they run out of time, the loss of concentration (voluntary by dismissing it or involuntary by failing a concentration check) or the spell being dispelled. Excluding concentration the same rules apply to non-concentration spells. A spell is active as long as its duration is not interrupted.

Antimagic field further states:

While an effect is suppressed, it doesn't function, but the time it spends suppressed counts against its duration.

The duration of spells / enchantments / magic items inside the sphere is not interrupted, as such they are active.

I'll elaborate with the following scenario:

You turn a medium-sized Barrel of Ale into a Helmed Horror (CR4), befriend it for an hour and it willingly lets you turn it into a Warhorse (CR 1/2) so you can ride it into battle.

Going by the rules on _combining magical effects the horror polymorphs into a horse because the second casting is deemed more potent by virtue of being more recent.

You mount your trusty war-casked horror and rush into the fray, barrelling into a creature surrounded by an antimagic field.

The instant the first limb of your mount touches the sphere you'll begin falling, a barrel crashing to the ground beside you.

The supression effect of the antimagic field does not interrupt the duration of the second casting of true polymorph. In essence, the barrel to helmed horror polymorph only gets supressed a second time by the antimagic field.

Due to the way it landed, the barrel rolls on further, exiting the antimagic field.

Once fully out of the field's range, your trusty barrel ultimately returns to the shape of a horse, unless you dismiss the second true polymorph.

  • \$\begingroup\$ What exactly does the "active" in the Antimagic Field spell signify, then? \$\endgroup\$
    – Cacse
    Commented Oct 11, 2019 at 12:41
  • 1
    \$\begingroup\$ @Cacse in this case? Existing. The barrel has 2 active True Polymorphs, but only one of them has an unsupressed effect, i.e. the horse transformation. one being supressed does not nullify the other if the horse transformation was dismissed or dispelled somehow. \$\endgroup\$ Commented Oct 11, 2019 at 12:43
  • 1
    \$\begingroup\$ @Scrawnoisis If "active" means "existing" then why would the word even be included in the text of the Antimagic Field spell? Of course it only suppresses magical effects that exist. Moreover, in common usage, "active" does not mean "existing", but rather something more akin to "engaged in action", which does not seem to be the case for a spell that, as per the rules for combining magical effects, does not currently have an effect. \$\endgroup\$
    – Cacse
    Commented Oct 11, 2019 at 14:15
  • 1
    \$\begingroup\$ The edit clarifies your usage but it still seems contrary to the common usage of "active". Is this interpretation of the word "active" coming from somewhere else in official source materials? \$\endgroup\$
    – Cacse
    Commented Oct 11, 2019 at 17:47
  • 1
    \$\begingroup\$ I don't see how this elaboration adds anything to the prior explanation. A concentration spell ceases to exist if concentration is not maintained, but as before, that does not mean every existing spell is active. The quoted line is stating a necessary condition for activity, not a sufficient condition. \$\endgroup\$
    – Cacse
    Commented Oct 13, 2019 at 17:23

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