Can Charm Monster be used to prevent a non-speaking creature from attacking the rest of the party?

Question

Looking at the Charm Monster spell, given that many monsters do not have a spoken language, the term "friendly to you" can be confusing. For example, my bard once charmed a Roc as it swept in to attack my party. The charm succeeded, but my DM argued that since I could not command it verbally, it was friendly to me only and therefore kept attacking the rest of the party. That was a quick way to nullify a successful casting of a 4th level spell.

Does the Charm Monster spell somehow allow a caster to prevent a non-speaking creature from attacking the rest of the party?

Answer 1

The monster wouldn't attack the party

The charmed condition only protects the charmer, as it states:

• A charmed creature can't attack the charmer or target the charmer with harmful abilities or magical effects.
• The charmer has advantage on any ability check to interact socially with the creature.

However, charm monster doesn't just charm its target, it makes it friendly too:

The charmed creature is friendly to you.

This adds a social dimension to the monster's perspective, which means the monster must reassess the situation. The Roc is no longer dealing with pack of prey, it's now dealing with a pack lead by a friendly, and its behavior should change accordingly.

But lets really dig into what friendly means, as described in Social Interaction (PHB p185):

In general terms, an NPC's attitude toward you is described as friendly, indifferent, or hostile. Friendly NPCs are predisposed to help you, and hostile ones are inclined to get in your way. It's easier to get what you want from a friendly NPC, of course.

Harming the caster's party is not helpful to the caster, in fact it's actively getting in the way and contrary to what the now-friendly monster is predisposed to do.

Resolving Interactions (DMG p244) states much of the same, but with extra detail:

A friendly creature wants to help the adventurers and wishes for them to succeed. For tasks or actions that require no particular risk, effort, or cost, friendly creatures usually help without question. If an element of personal risk is involved, a successful Charisma check might be required to convince a friendly creature to take that risk.

The only adventurer the monster wants to help is the caster, but nonetheless attacking the party is the opposite of helpful for the caster. Leaving the party alone is a task that requires no effort, no risk, and no cost, it's basically the least the monster can do for the caster and so it should typically do so without question.

This is the baseline behavior for the monster once charm monster takes effect. The caster doesn't need to ask the monster to become friendly, it just is friendly and the two don't need to share a language for this to be true.

Still, the monster will continue to be indifferent/hostile towards the rest of the party. The caster is an excellent position to direct the situation towards a favorable outcome, especially given the advantage to ability checks granted by the charmed condition, but if the two sides have some unresolvable conflict then the situation could progress into a combat encounter anyway.

For example, if that encounter with the Roc happened in its nest, then ignoring the Roc's warnings to approach its chicks/eggs could easily spur the Roc's aggression and retaliation. Or alternatively, if the Roc were literally starving, then not eating the party is a risk for the Roc, and a successful skill check might be necessary to keep the Roc at bay.

Answer 2

Guidance is minimal, it is up to the DM.

There is no additional guidance given to the DM for running charmed NPCs or monsters beyond what the players already know about the charmed condition, which states:

A charmed creature can't attack the charmer or target the charmer with harmful abilities or magical effects.

So on the surface, the charmed condition only restricts how the charmed creature interacts with the creature causing the charm. Beyond this, it is largely up to the DM.

That said, a very similar question, Can a creature be too stupid to know whether the companions of the person charming it are companions?, deals with this issue, and I think V2Blast's answer there provides some good insight:

The spell's effects relate to "you or your companions", regardless of whether the target realizes they're your companions

The charm monster spell description says (emphasis mine):

You attempt to charm a creature you can see within range. It must make a Wisdom saving throw, and it does so with advantage if you or your companions are fighting it. If it fails the saving throw, it is charmed by you until the spell ends or until you or your companions do anything harmful to it. The charmed creature is friendly to you. When the spell ends, the creature knows it was charmed by you.

(The charm person spell has mostly identical wording, aside from only working on humanoids, and otherwise works the same way.)

The spell doesn't say these things depend on whether the charmed creature realizes they're your companions. As such, this means these effects - advantage on the save if companions are fighting it, and the charmed condition ending if your companions do anything harmful to it - apply simply based on whether they're actually your companions, regardless of whether the targeted creature knows they are.

The spell doesn't provide an in-universe explanation for how the spell determines that the creatures are your companions, so you may have to substitute your own reasoning to explain it in-game. However, out of game, that is simply how the spell works; it seems reasonable to interpret "your companions" as referring to the other player characters (and any possible allied NPCs) if the caster is a player character - assuming the PCs are all working together as a party, of course.

Answer 3

You can get around the issue with body language or spells

Charm Monster merely states that

It must make a Wisdom saving throw, and it does so with advantage if you or your companions are fighting it. If it fails the saving throw, it is charmed by you until the spell ends or until you or your companions do anything harmful to it. The charmed creature is friendly to you.

So, while it gets an advantage for its save based on your companions, it is only friendly to you, not your companions, and could potentially attack them. As Ruse's answer points out, the creature is friendly to you, so it might not attack them which it would understand is not helping you. I think it is up to the DM to resolve if the friendlyness, or other instincts like hunger, territoriality etc. win out here.

However, even if the creature does not have language, if you wanted to communicate to it more explicitly that you do not want it to attack you companions, there are options.

First, you could use body language to show your intentions, e.g. by interposing yourself between them and the creature, by making arm movements shooing it away, by angry yelling and shaking your head when it attacks, etc.

Second, you could use other spells to get around that limitation, and make it understand that as your friend, it should not attack your companions. Two options for this are:

• Speak with Animals. If the charmed creature is a beast, and you are able to cast speak with animals, you can communicate with it that way. You need to have a feat or some class levels in a class other than wizard, to use this option.

• Telepathy At 8th level, this is a costly option, but as your friend the creature should be willing to let you cast spells on it. The spell states that "Until the spell ends, you and the target can instantaneously share words, images, sounds, and other sensory messages with one another through the link, and the target recognizes you as the creature it is communicating with. The spell enables a creature with an Intelligence score of at least 1 to understand the meaning of your words and take in the scope of any sensory messages you send to it." So as long as it has an Intelligence of at least 1, you will be able to let it know it should not attack your pals. This spell is on the wizard list, so no issues there.

Answer 4

Charm Monster (and Person etc) should charm them to all friendlies.

After some consideration, I think I'd have to disagree with your DM (and others) in the interpretation of the charm spell wording. The reason is in the logic behind the mechanics themselves.

As mentioned in a comment on Groody's answer, the plural for "you" in English is the same as the singular. So you can just as easily take the line "The charmed creature is friendly to you" to mean you, as a group of adventurers. This is not merely wishful thinking--I think it's the designer's intention, as it also makes more logical sense:

The mechanic of breaking the spell when an ally attacks the charmed creature is clearly to represent a response to being hurt as destroying trust in the aggressor, which is a primal and simplistic response we all understand. This is why the spell is not broken by just any attack; but specifically from a certain source. In order for this to make any sense, the aggressor must in some way be associated with the charmer. In essence: "you (or your friends) hurt me, you can't be my friend after all", and thus the trance is broken.

Now you could argue that it's actually just a totally arbitrary effect of the spell and not based on such a concept, but even in simple game-balance terms this is problematic. If you charm a monster and it stops attacking you, but now nobody else can touch it without effectively nullifying your action, I would argue there's very little utility to the action at all unless alone (rare, in most games); which, you no doubt found out first-hand.

Another telling feature, (that you actually mention in a comment above), is when Charm is applied back against the players it doesn't then get broken if the player is attacked by another enemy (because the player is only charmed by the one enemy). So, for consistency, charm-induced 'friends' ought to be taken to include all those that could break it.