As shown in this question and answer, I am confused by the terms "hostile" and "enemy". So I was wondering if in my own game I could simply remove the "hostile" from the opportunity attack rules, because I think there it is particularly useless.

Currently, the rule on opportunity attacks says (PHB, p. 195; emphasis mine):

You can make an opportunity attack when a hostile creature that you can see moves out of your range.

I'm thinking attacks are allowed against allies; why shouldn't attacks of opportunity be?

Would there be balance issues if I house-ruled that opportunity attacks can be made against any creature, not just hostile ones? Are there any spells, effects or others that now unexpectedly work differently?

The revised rule would read:

You can make an opportunity attack when a creature that you can see moves out of your range.

Edit: Based on one of the answers about the warcaster, I can see why it shouldn't be like this. Now one of the reasons to allow one to attack an ally would be for example when you get turned against them, however they are not hostile towards you. So a solution should allow AoO against enemies that are not hostile towards you, but it shouldn't be possible if you don't actually mean to harm the enemy.

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    \$\begingroup\$ @guildsbounty: I feel that, taken together, your comments do constitute a valid answer to the question. And it's one I would upvote over the others, if you actually posted it as an answer. \$\endgroup\$ Commented Sep 2, 2019 at 11:27
  • \$\begingroup\$ @guildsbounty: As Ilmari Karonen said, you should leave that as an answer if you feel it addresses the question in some way. Comments are for asking for clarification or suggesting improvements to the question. \$\endgroup\$
    – V2Blast
    Commented Sep 3, 2019 at 7:33
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    \$\begingroup\$ I'm curious what situations you're trying to support with this. (I.e., which consequences of this change are the intended ones, and which consequences are the unexpected side effects.) \$\endgroup\$ Commented Sep 6, 2019 at 14:42
  • \$\begingroup\$ @Admiral Jota I would like for the players to be able to make an attack of opportunity against any creature they want. An unexpected side effect would lead to cases where they now make an AoO even though generally they do not mean to harm the creature. \$\endgroup\$
    – findusl
    Commented Sep 6, 2019 at 15:34
  • \$\begingroup\$ @findusl Given that, I wonder if just switching it from "...when a hostile creature..." to "...when a creature you're hostile to..." might work for you. \$\endgroup\$ Commented Sep 6, 2019 at 16:03

5 Answers 5


This Slightly Increases the Power of the Players

This is one of those rule changes that doesn't directly increase power level but instead increases the options available to the player. Fundamentally it should be balanced because NPCs and PCs can both use it, however it is the sort of thing players are far more likely be take advantage of than monsters.

A couple of examples where players could use this to their advantage:

War Caster Feat

As Patron Paton excellently points out, the War Caster feat has the benefit:

When a hostile creature's movement provokes an opportunity attack from you, you can use your reaction to cast a spell at the creature, rather than making an opportunity attack. The spell must have a casting time of 1 action and must target only that creature.

Your change would allow buff and healing spells to be cast on allies as they leave your reach. This significantly improves the action economy for support casters and opens up a lot of new combat combinations.

Raging Barbarians

AuxTaco points out a case where this rule could be used to keep your barbarian raging. The rage feature requires you to attack or take damage since your last turn or your rage ends. This modification would allow the barbarian to run past an ally and take damage thus continuing their rage, or alternatively the barbarian could attack an ally with their AoO to achieve the same result.

This is a somewhat meta-gamey option but it is a valid option per the rules with your modification. Perhaps situational and unlikely to make a major difference overall, but still a net positive for player options.

Other niche combinations

The two situations above are just examples of the kind of trickery you can pull off with this rule change, there are likely many more.

I can think of a strange combinations of a character who gains a benefit from reducing a creature to 0 HP and a death domain cleric who heals more effectively from 0 HP. Combining these abilities to knock down and then heal an ally could provide a net benefit to the party overall.

Only creatures you are hostile to

Based on some comments/edits you made and Admiral Jota's answer I understand you have recognised the issues with this rule and instead are considering a smaller modification.

You can make an opportunity attack when a creature you are hostile to that you can see moves out of your range.

The problem with this in my mind is that the players determine who they are hostile to and can easily exploit this. "I am hostile to the rogue, he stole my orange juice this morning". A good DM can easily deal with this but it would be better not to leave it open to interpretation.

Creatures you mean to harm

Your other "mean to harm" suggestion would have a rule something like this:

You can make an opportunity attack when a creature that you can see moves out of your range, provide you mean them harm.

This fixes some of the issues with the "that you are hostile to" variant but does open up some new ones. What counts as "mean them harm"? Some spells cast with War Caster deal no direct damage but are valid options.


Overall this house-rule isn't particularly unbalanced but does open up some interesting combinations. As most of these combinations actively reward intelligent play from the party I don't really consider that a bad thing. I suggest you allow this on a play-test basis and be prepare to modify/remove it should it cause issues.

  • \$\begingroup\$ I'm not sure that changing wording of the rule for making opportunity attacks would change how War Caster works, since the War Caster feat itself still explicitly states "When a hostile creature's movement provokes an opportunity attack from you..." (emphasis mine). Even if non-hostile creatures can provoke OA's, that doesn't mean those OA's would qualify for that feat. \$\endgroup\$ Commented Sep 11, 2019 at 14:28
  • \$\begingroup\$ @AdmiralJota I was assuming that the change would also be applied to the War Caster feat. If it wasn't that would of course mean that example is not relevant. \$\endgroup\$
    – linksassin
    Commented Sep 12, 2019 at 0:19

From memory the War Caster feat is the only thing that might work well with this. Its third benefit is:

"When a hostile creature's movement provokes an opportunity attack from you, you can use your reaction to cast a spell at the creature, rather than making an opportunity attack. The spell must have a casting time of 1 action and must target only that creature."

Assuming you also change the 'hostile' in this wording, this means a spell caster could cast a one action buffing/healing spell against any ally that leaves their melee reach.

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    \$\begingroup\$ Welcome to rpg.se! Take the tour and visit the help center for more information. Great catch with this answer, that is a subtle point that would be easy to miss. I think you could slightly improve the answer if you add some assessment as to how this would therefore affect the overall balance of the game. Either way you have my upvote. Thanks for contributing and happy gaming! \$\endgroup\$
    – linksassin
    Commented Sep 1, 2019 at 12:51
  • \$\begingroup\$ The answer is really nice and I upvote but I refrain from accepting it so far, because its only one specific case "from memory". That is not really a complete answer. But there is no better answer... Should I anyway accept it? \$\endgroup\$
    – findusl
    Commented Sep 3, 2019 at 4:18
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    \$\begingroup\$ @findusl, whilst this answer got a lot of upvotes, there's no rule on RPG.SE saying that you must accept the most upvoted answer if you don't think it was the best answer to your question. Whilst this gives an interesting and potentially unexpected consequence of the rules change you're proposing, you were asking a broad question about your game's overall balance and this answer is very narrow in scope, so I can absolutely believe that you might not think that it's quite what you were looking for. \$\endgroup\$
    – ymbirtt
    Commented Sep 3, 2019 at 9:29

A very specific true story where this would have helped:

The party enters a large room with visible enemies at the far end and a side hallway 80 feet from the entrance. The (small) PC monk wins initiative and Dashes forward. At the end of his move, he becomes aware of a large number of archers waiting in the side hallway for their turn to come up.

The barbarian is next. With his 40' speed, he can Dash to and block the side hallway, but would really prefer not to be peppered with arrows. He can't Rage to resist the damage; it would wear off immediately:

Your rage lasts for 1 minute. It ends early if you are knocked unconscious or if your turn ends and you haven’t attacked a hostile creature since your last turn or taken damage since then. You can also end your rage on your turn as a bonus action.

With your revised rule, he could Rage, Dash by the monk (who punches him in the arm as he runs by), block the hallway, and resist the coming onslaught.

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    \$\begingroup\$ I'm not sure why you got a -1 for this, this is a really interesting situation, and gives a good example of an edge case that would be triggered by OP's proposed rules change. I'm interested in knowing if your GM allowed the monk to punch the barbarian to sustain the rage, and how the players then felt about this ruling. \$\endgroup\$
    – ymbirtt
    Commented Sep 2, 2019 at 9:30
  • \$\begingroup\$ @ymbirtt I'll ask him tomorrow; I (the barbarian) ended up taking a path that wasn't near the monk and the question never came up. 19 AC was enough to keep me alive. \$\endgroup\$
    – AuxTaco
    Commented Sep 2, 2019 at 9:35
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    \$\begingroup\$ Hi AuxTaco, thanks for joining rpg.se! Take the tour for the usual badge if you get a chance. You got an upvote from me but the downvote may have come from the fact you only mention one use case and make no assessment of the overall balance of this rule. If you edit to also include that this would be a great answer. \$\endgroup\$
    – linksassin
    Commented Sep 2, 2019 at 9:58
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    \$\begingroup\$ Note in this particular situation the barbarian could've just picked up a rock and thrown it at the archers. Would that have done much? No. But he would've attacked a hostile creature, thus keeping rage up (attacks don't have to hit or do much damage). \$\endgroup\$
    – Cubic
    Commented Sep 2, 2019 at 10:22
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    \$\begingroup\$ @Cubic No action available. Dash to get to the hallway, Rage for the resistance. I doubt the DM would have allowed a free item interaction to potentially do damage. \$\endgroup\$
    – AuxTaco
    Commented Sep 2, 2019 at 10:24

There would be "altered play" but not necessarily balance issues.

With most rules, they are written in the best possible fashion by the developers in order to promote balance and fairness. However, it is even indicated within the Player's Handbook and Dungeon Master's Guide that these rules should be a guideline, with ample opportunity to tweak them to any way you deem fit.

Since this rule would apply across ALL beings in your campaign(s), it is not exactly a "balance" issue, seeing as all creatures are affected by this equally, therefore preserving balance. It would, however, create some crazy, and perhaps convoluted fighting scenarios, though you aren't being forced to utilize your reaction in the form of an opportunity attack in the first place, again, mitigating the impact this house-rule would have on the overall flow of battle/the campaign.

As far as affecting certain features, spells, etc., most of these things are worded in a way where your attacks are still limited to specific targets. If you wish to then extend this house rule to these situations, you may experience some strange circumstances, but again, it would all be still be balanced since enemies would undergo the same changes.

A creature can be hostile without being an enemy.

While not a direct answer to your question, as it is all up to interpretation, type of campaign you are running, how combat heavy it is, along with many other things, you can attack a friendly or neutral PC or NPC with an opportunity attack under the correct (and very simple) circumstances.

In my own form of RAI: The difference between Hostile and Enemy is that an enemy is counter to your alignment, goals, or other way of virtue that inhibits it from being your ally or even neutral toward you. A hostile creature (or other being) is something that means to do you harm, which can definitely be a friendly who is intending to cause you harm (even if in a playful manner).

However, RAW indicates for "Hostile" (DMG Pg. 244):

A hostile creature opposes the adventurers and their goals but doesn't necessarily attack them on sight. For example, a condescending noble might wish to see a group of upstart adventurers fail so as to keep them from becoming rivals for the king's attention, thwarting them with slander and scheming rather than direct threats and violence. The adventurers need to succeed on one or more challenging Charisma checks to convince a hostile creature to do anything on their behalf. That said, a hostile creature might be so ill disposed toward the party that no Charisma check can improve its attitude, in which case any attempt to sway it through diplomacy fails automatically.

Unfortunately, there is no exact definition on what makes an "enemy" an "enemy", so feel free to adopt my own interpretation from above or develop your own beyond what is indicated in my answer.

  • \$\begingroup\$ You might want to consider looking at the linked question about hostile and enemy and giving an answer there. Your interpretation is definitely new to me, not sure what the effects all are. \$\endgroup\$
    – findusl
    Commented Sep 2, 2019 at 10:02
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    \$\begingroup\$ I decided to put in some RAW from the DMG as to what a hostile creature is in THEIR defintion. \$\endgroup\$ Commented Sep 2, 2019 at 10:19
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    \$\begingroup\$ I like this source a lot, I think you should really put it on the linked question rpg.stackexchange.com/a/154505/51849 \$\endgroup\$
    – findusl
    Commented Sep 2, 2019 at 10:28
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    \$\begingroup\$ I went ahead and added a slight revision of my answer here to that linked question. Just for you ; ) \$\endgroup\$ Commented Sep 5, 2019 at 2:58

Based on this comment you made:

I would like for the players to be able to make an attack of opportunity against any creature they want. An unexpected side effect would lead to cases where they now make an AoO even though generally they do not mean to harm the creature.

In order to achieve this while limiting the the unexpected side effects, you could choose to change the wording of the rule to:

You can make an opportunity attack when a creature you're hostile to that you can see moves out of your range.

I believe this should still be within the RAI, but would permit characters to use opportunity attacks without needing to rely on the mental or emotional state of the target. This is also more similar to the original wording than your initial proposal, which should reduce the unintended side effects.

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    \$\begingroup\$ I guess i'm still confused (even without getting into RAI territory - which you should also specify if that's Intended or Interpreted). That comment can't be taken out of context from the question itself (because that comment could also disappear), but doesn't that still make this about hostile which OP is specifically wanting to remove? How does this enable attacking an ally? \$\endgroup\$
    – NotArch
    Commented Sep 9, 2019 at 19:17
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    \$\begingroup\$ @NautArch from other answers I have learned that being able to attack allies without some limitations you could heal them with the warcaster. This is in my opinion a balance issue and enough people upvote it as such. However with the wording in this answer that issue is fixed and you would be able to attack an ally if you get turned against them, by say enemies abound, without them having to be hostile. Do you think I should extend my question with the balance answer issue? \$\endgroup\$
    – findusl
    Commented Sep 10, 2019 at 6:23
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    \$\begingroup\$ @NautArch I understand this answer is not perfect based on the question, but it is actually good based on my problem, that you can find in the linked answer. I'm not sure how to handle this, as I actually did not want to put the rather controversial topic of whether hostile is subjective in this question but leave it in the linked one. \$\endgroup\$
    – findusl
    Commented Sep 10, 2019 at 6:34
  • \$\begingroup\$ @findusl This is a great opportunity to look at how you ask questions! Focusing on the problem is usually the best way (but often the hardest.) If this answer helped clarify your particular problem, it may be possible to update your question accordingly (although try not to invalidate existing answers.) The goal here is in solving problems, not providing answers. The better you can formulate and ask your problem, the better answers you'll get :) \$\endgroup\$
    – NotArch
    Commented Sep 10, 2019 at 14:42

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