I'm running a campaign for five sixth level players and the bard has hypnotic pattern. Whenever the party runs into any fights with enemies who can speak, they always find some way of making an enemy incapacitated or doing non-lethal damage so they can question them later.

This always makes me have to think of things for that otherwise silent NPC to say and it feels bad to make them say nothing and "force" the party to just kill them.

Question:

Is there any smooth roleplaying way to handle this situation?

There are other benefits to capturing an enemy besides just information

Rather than every NPC either having secrets or nothing, consider other things for your NPCs to offer the party.

Perhaps this particular NPC enemy was just a mercenary for hire and has no real loyalty to the villain. Perhaps they'll leave with their lives if you let them live, not following the villain anymore, but if you offer to pay them, they might join as an allied NPC (although you don't want to let this happen too often, otherwise your players will want to amass an army of cannon fodder, but it's an example of an NPC who is useful for reasons besides info).

Silent NPCs?

Also, I must question the use of "silent NPCs". This implies that you haven't really thought about why that particular NPC is there, what their motivations are for helping the villain. If it's just another cookie-cutter loyal cultist, then fine, just have them ramble about how their time has come and how the PCs won't live to see it, etc, etc, just kill them. But for other, more rational NPCs...

Not every NPC needs to have a rich personality with a huge backstory or anything, but they should at least have the basics of a personality, even if it's just one simple trait and a reason for being there. The DMG has a whole chapter on creating NPCs, with some advice on "Quick NPCs" and tables to roll on to quickly generate on-the-fly personalities (pages 89-91). You can use this to quickly whip up a personality, maybe even only after they've been captured, but since it's quick, ideally before. This might also influence their decisions before they're captured, since not every enemy wants to fight to the death.

Surpriser provides in this comment an account of how successful this can be and how interesting the outcomes it leads to can be:

I had a captured bandit tell them how he was only there because of his debts, which made him fear for his life. They actually paid off his debts and now he is a friendly ally. Made a very nice contrast to the bandit leader who spat at them and told them to sod off in very clear words after being captured. They were suitably impressed.

I think this nicely illustrates the potential for a little characterisation of NPCs and how that can help to enrich the story being told.

Related: What are the stages of influencing Hostile NPCs?

Possible solutions:

• Anticipate and reward the behavior. Whenever you design a combat encounter, think of some more or less interesting tidbit of information you can reward the party with when they manage to capture and interrogate an opponent. It does not even need to be that useful. You can also use this as an opportunity for worldbuilding and characterbuilding.


• Confront the party with opponents they can't communicate with. Beasts, undead and other creatures which lack the INT score to be capable of language are the obvious solution. But you can also do this with intelligent opponents. They might simply not speak or understand any language the PCs are capable of.


• Add time pressure to the situation so they don't have the time to interrogate prisoners.


• Confront the party with opponents who simply can not be captured alive. They disintegrate, disappear or get banished to a different plane when they are defeated.


• If you really don't want to provide the party with any useful information but can not use any of the above methods to prevent the interrogation, have the prisoner lie to the PCs (from Surpriser's comment). When the PCs have the means to easily detect lies, then consider the posssibility that the prisoner is misinformed. Most lie detection methods can not detect a misinformation when the person who speaks it thinks it is the truth. Also, most lie detection methods require some die roll. You could do a hidden roll and then lie about the result, if you consider that ethical (controversial topic).

Give NPCs a line each.

Drawing inspiration from the later Metal Gear Solid games, give every NPC one or two things they will reveal when interrogated. It may be irrelevant, or it may be useful. Some examples:

• The location of where they hid their treasure


• The location of their allies


• The password to their lair


• The location of a trap, and how to bypass it


• Some piece of lore


• Information on a clue the PCs missed earlier in the dungeon that you hoped they would find, such as a hidden door, or the answer to a puzzle they didn't get

Set an expectation that each NPC or group of NPCs, when questioned, will only reveal one piece of information. That's all they know. The information they give up represents everything gained from an entire interrogation session. Further interrogation will have no effect.

If you had not planned for interrogation, invent something minor on the spot. Place some minor treasure, for example. They may give the same information as a previous interrogation (maybe everyone in the dungeon knows about the pit trap, but not about what lies beyond it).

Handle the entire interrogation in one roll, or some similarly quick method, and move on.

Other solutions:

• Have some enemies speak no language in common with the PCs. Obviously it's unreasonable for goblins not to speak Goblin, but not every creature necessarily speaks Common.


• Require a single Intimidate check, opposed perhaps by the creature's Charisma save. No retries. A failure means this one won't talk no matter what. This saves you a lot of time.


• Impose some ad-hoc penalty for attempting to deal non-lethal damage, so that players only attempt to incapacitate the important enemies. Be careful, as the players may resent their ability being nerfed.


• Some enemies will flee or fall on their sword rather than allow themselves to be captured.


• Interrogation takes time and makes a lot of noise. The enemy may send a rescue party to save their captured friends.


• The enemies get tired of the PCs interrogating and plant false information to harm or hinder the PCs, such as giving them fake maps with explosive runes. (Thanks Chronocidal)


• The captured enemies have a habit of giving misinformation because they're genuinely mistaken. They believe rumours or misinformation, such as false stories of hidden treasure guarded by dangerous creatures. (Thanks Temporalwolf)

From a roleplaying perspective it can be used for several purposes:

• slip in story hooks for future plot lines "I never wanted to live the bandit life. I'm a good person - A FARMER! It's just my land got swallowed up by the mist. A mans got to eat! Not worth my life going out in that to try and scrape dirt."


• have your big boss misinform underlings to lead the party into traps


• Reiterate information previously given


• Colour in the world they live in "Boss Bandit will chase you from the Unforgiving forests to the South sea. The Shield Clan themselves won't be able to protect you. Your corpses will be left on the Lone Mountain for the Roc's to pick clean."

From a meta-game/table management perspective, if you are willing to give out one or two info nuggets per throw away NPC you can out of game discuss with your players how interrogations get RPed. If you find it too difficult to role play every random cultist/bandit/goblin then let your players know that. A decent alternative to RPing these encounters is that they get a certain number of questions of direct role play then "after 2 hours of further interrogation no new information is gained".

I'd hope that your players are cooperative enough to accommodate your difficulty with this play style and work with you to make sure everyone is having an enjoyable experience.

There are a lot of good answers here. In general, I think the best way to handle things is to let your PC's capture/interrogate prisoners. There are many approaches you can take to minimize the damage and even make it beneficial for your story. Here I've listed some approaches I personally take when GM'ing, and some examples from my most recent campaign.

First, you can always limit how much the NPC's know or can share.

A recent adventure I just finished is a good example of this. They were fighting a bunch of kobolds, and (being cowardly) a couple willingly surrendered after the rest of their group was slaughtered. The only problem? They only spoke Draconic. The PC's still managed to negotiate their surrender through body language and tone of voice, but could hardly interrogate them.

And even if they speak Common, nothing says that they have to speak good Common. some of my NPC's with Common as a second language speak such broken Common that the my players have to figure out what the NPC is saying before they can respond. I had another kobold later who said things like, "Leader big of self. Kobold help to human, Leader no see." (Translation: "Our leader is arrogant. If we help you, our leader can't know about it.") My players enjoyed translating and expanding to glean what understanding they could, though the kobold's Common skills were too low to say anything too complex.

Second, be ready to make up personalities on the fly.

The kobold with broken Common was originally supposed to be a "silent NPC" as you termed it. He was a dragonwrought sorcerer serving as the lieutenant to a baby dragon. I designed it as a straight-up combat encounter, and was surprised when the PC's immediately tried to negotiate instead of fighting (despite being assaulted by crossbows and traps through the whole dungeon). I had a loose idea of their motivations before, but as soon as the party started negotiating, I finalized why the dragon had taken a band of kobolds far from their usual territory, set up in that particular place, and had been harassing the local town.

Further, the dragon, which was mostly a plot device, suddenly required a personality. As a young thing, I made it naive but full of itself. "I am dragon, hear me roar! (Even if I'm the size of a house cat!)" The silent lieutenant (mentioned before), became the patient-yet-put-upon leader seeking to take the unreasonable demands of their child leader and implementing them through his own wisdom. He was sharp, despite his poor Common, and a shrewd'ish negotiator once the dragon dispatched him to do the boring part of negotiating. And yet, his faith in the leadership of the dragon never wavered, because that was simply the (semi-religious) order of things. For a kobold to not obey a dragon was inconceivable to his world view.

That gave me enough to work with for even an extended roleplay, and it just came out of the simple questions that I had partially fleshed out for the adventure already: "Why are they here? Who is in charge? Why do others follow them?"

Third, intimidation/persuasion/charm are not 'roll to get your way'.

To escape the combat encounter with the sorcerer and dragon, they had to make a series of about half a dozen various persuasion and intimidate checks - each one enhancing the effects of their roleplay - until they had established that they were willing to negotiate, that fighting them would probably be a bad idea (despite being at a tactical disadvantage, unknown to the players), and (very importantly) having played to the dragon's ego. Despite some generally high rolls, if they had said the wrong things, they could easily have caused combat instead of avoiding it (one insult and that would be all she wrote, unless they got a natural 20, which would only have negated the penalty).

Another example, from an earlier adventure, was when the fighter intimidated a scholar to get an important piece of (divine) information out of him. The fighter didn't scare the scholar nearly as much as the gods themselves, so it was doomed to failure from the start (especially since he was their ally, so he knew deep down that any threats were empty, probably). However, with a very high intimidate check, he basically choked up and just completely blanked out.

Applied to your game, for prisoners, who are they more afraid of? The party who might kill them, or their boss who'd make them eat hot coals (and then get really nasty)? Unless the party can convince someone in such a situation that they are willing to do worse than the villains, important information can easily be withheld for that reason. Which brings me to...

Fourth, Charm is not all powerful!

All Hypnotic Pattern does is Charm the target(s) (and incapacitate, but that's not relevant to interrogation). A Charmed target (1) cannot attack the charmer, and (2) the charmer has advantage on any social ability check. It doesn't mean they're under truth serum. Someone who's afraid of being tortured to death for betraying their leader is still going to be silent, no matter how good of a friend is asking.

They may even simply be too loyal. If you know the combination to the safe at your workplace, are you going to tell that to even your best friend in the world without a very, very good reason? (And the more likely that others will know it was you that told them, the less likely you'd probably be to stick your neck out.

Well, I hope that helps!

Maybe the enemy leadership keeps their grunts in the dark so they know very little. Even better, perhaps the grunts are lied to. In fact, my preference for this would be for the enemy leader to send a semi-weak squad of combatants carrying false knowledge to try to bait your party into a more dangerous ambush/trap.

Alternatively...

Depending on how intelligent, fanatical, desperate, or prideful your adversaries are, they may take countermeasures to avoid having themselves spout information in the event of being captured.

For example, a group that expects a fight might have preemptively cut out their tongues. That gives you a flavorful 'devoted fanatic' theme.

If your enemies take pride in their combat skills, perhaps death is (in their minds) preferable to capture. Find some method for them to choose kill themselves in that scenario. Hidden knife, poison tablet, etc.