# How can I replace a player character with an impostor without alerting the group?

I recently picked up a book of example NPCs (the Pathfinder NPC Codex, incidentally) and came across an entry for a "master spy". In the flavor text, it describes how his "secret identities have secret identities" and how he might pose as another NPC or even a player character temporarily.

This of course got the wheels turning in my head, and I can imagine a scenario where the party (having encountered this master spy in the past and knowing of his skills) kicks down a door to discover one of their own, bound, gagged, and stripped of their belongings. Then the pieces will come together and they'll realize that they've been deceived by the spy, and that he has been in their company for several hours, if not days, acting as their comrade would act and gathering privileged information. If said information lets him get the leg up on the party and beat them in a race to and important something or someone, all the better.

I could obviously work with the player in question to make the deception happen, but I think the reveal would be much more powerful if all the players were deceived, and could work out the details for themselves from the hints and foreshadowed elements, so my question is this: how do I separate a character from the party and replace him with a doppelganger without rousing the suspicions of player in question or the party at large?

One idea I've come up with is to isolate the character and render them unconscious (during which time the imitator makes the switch) in a secondary encounter, then have the rest of the group happen upon the unconscious character a short time later -- from that point forward, the player's actions are actually being carried out by the imitator in disguise until the reveal. This feels somewhat heavy-handed, so any more elegant ideas would be appreciated.

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The ultimate twist and balancer: Have the party stumble upon itself, every member bound and gagged and stripped. Imagine the surprise of all the rival master spies who each have taken over a different party member, believing the rest of the guys to be the genuine stuff. Imagine the surprise of the party. Pure win. :] – OpaCitiZen Mar 31 '13 at 23:21
Related (from the other side of the table): Tips on playing a character whose goals run contrary to his outward actions (to the other PCs) – BESW Apr 1 '13 at 5:10
@OpaCitiZen that sounds like a session of Paranoia. Brilliant. – Problematic Apr 1 '13 at 12:22

I strongly advise you to at least involve the player whose character is temporarily to be replaced. There are at least two good reasons:

• you betray the player in question by replacing his character with a replica just like that. He won't notice until the surprise and I wouldn't appreciate a revelation like .. and look, there is .. yes, you! And the character you just played since the moment your hero left the room is actually .. well, not you .. Players usually don't like losing control of their character without a warning, explanation or chance to resist.
• if the player is actually involved he can play along with your plot much better, as you can give him information about the spy's motivation etc. Being partially involved in taking plot decisions and acting against the group with a good excuse (like this one) is usually great fun for both the gamemaster and the involved player.

Furthermore, by involving the player in this scenario he will have the chance to play the spy a tiny bit different than his character - this feels more natural when the acting is revealed and also gives the other players a fair chance to detect him.

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+1, this is basically what I wanted to say but am too sleep-deprived to articulate. Especially the part about involving the player whose character is replaced. – thatgirldm Apr 1 '13 at 2:30
Although I find these answers wise advice, I can't upvote them, since they don't answer what's being asked. – Flamma Apr 1 '13 at 7:09
Not to mention that players LOVE to get in with a GM's plan. – The Jug Apr 1 '13 at 15:28
Best advice, but doesn't really answer the q. – deworde Apr 2 '13 at 9:53

I could obviously work with the player in question to make the deception happen, but I think the reveal would be much more powerful if all the players were deceived

I think you should, nevertheless, work with that PC. Otherwise the reveal will feel a little bit too arbitrary, and rob that particular PC's player of agency.

The game isn't just about the DM. Which would seem more fun as a player: getting to secretly play as a doppelganger of yourself, or to find out along with everyone else that you haven't been playing the character you thought you were?

There are also some logical inconsistencies; how do you explain powers that the PC has that the doppelganger doesn't?

The reason your idea feels heavy handed is because it is heavy handed. One of my least favorite twists of all time was in Babylon 5, when one character was suddenly revealed to be a spy for the enemy and written off the show. It didn't match with any of the narrative leading up to it, it felt arbitrary, and negated some interesting moments for that character. (Of course that's because it was arbitrary; they wanted to get rid of that particular actor.) The situation you describe isn't quite so bad, since the PC gets to return in the end, but ultimately you risk the same sort of reaction from your players.

What if the PC had a cool scene of character development during this whole scenario? Suddenly, that didn't happen after all.

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Good point about character development, thanks. – Problematic Apr 1 '13 at 12:28

Regardless of whether this is a good idea to spring on the players or not, you don't need to be heavy-handed and have a big to-do about knocking out a PC and having them be unconscious for a while. If it's a master spy, they only need a moment for the switch.

Are all the PCs conjoined twins (er, quintuplets?) – are they literally joined at the hip? Is it established that they're so paranoid that they have strict protocols about always being in sight of each other, no matter what embarrassing personal hygiene they have to tend to? Do they travel everywhere tied together with lead ropes?

No? Then there will always, always be "in between" moments where PCs are away from each other, even if only for a few moments. Just do the reveal, and let the players try to figure out when the switch happened. You know that it happened in one of these innumerable off-screen moments of separation, so you just need a general timeframe for when it happened, not a big set-up and a specific moment played out at the table. "You remember when you all split up to go shopping...?" or "You all insisted on buying individual rooms at that inn a week back. Well, one had loose window..." is massive amounts of room to make the switch, and even something as small as "yeah, so-and-so never actually came back from their trip behind the bushes one night around the campfire, it was the spy all along" is just as good.

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Completely correct. Oddly, The less opportunity you create specially for the master spy, the more plausible the switch will be. (The last time a group PC became a traitor was in my Star Wars game, and the group were going through customs at the time. All I did was roleplay mini-incidents for two other PCs in the group, thereby establishing that stuff happened without drawing any attention to the switch.) – Tynam Apr 1 '13 at 13:40
+1: This is the best answer for the question that's being asked. – deworde Apr 2 '13 at 8:30

I once heard Sandy Petersen, at RQCon II, talk about a Call of Cthulhu campaign where he pulled a similar trick. He worked with the player being impersonated, and the two pulled it off. The party eventually found the original Investigator, and he insisted they test the imposter for humanity. The imposter had green gel for blood. But then the player (of the imposter) insisted that the original Investigator be tested the same way, and the original Investigator (?) also had green gel for blood. The player, now of both, held a fast conversation:

“You stay East of the Mississippi.”
“You stay West of the Mississippi.”
“Deal.”

BESW asked me to distill some advice from this anecdote. The freedom the GM has depends on the maturity of the players, and of his own, of course. The more he can depend on the players to act from the characters' standpoints and not from reward-based thinking, the more he can pull off tricks like this.

There were some things I left out; the convention was nearly 20 years ago. Sandy added a lot of flavor. The characters were storming a village, accompanied by a mob of farmers, and in a thunderstorm. When the lightning flashed, some of the mob looked inhuman. It turned out that they had green gel for blood too, and all the players later suspected themselves.

• Tricks like this require mature players.
• The GM has to be able to communicate with the players privately, with other players not taking that into account.
• At the denouement, when the GM took an active part in the unraveling of the deception, he involved the characters in an interesting and thematic way.
• The GM did not punish the player for his cooperation.
• Except for a typically CoC-ish surprise.
• The player was allowed to resolve the dilemma in a way satisfactory to the game.
• The player was not called to damage the original character's companions, possibly unlike the OP's situation. However, he was not given any explanation of what happened. Actually, he might have been told that something weird had happened, but not told he was an impersonator, which would make this anecdote not really apply to the OP.
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I think the other answers have given a pretty good case for involving a player in this. If, however, you absolutely do not want any player involvement, what about replacing one of the party's more trusted NPC companions? The end result is the same, all the players are surprised, and you haven't removed anyone's agency! The one catch is that you need to have a trusted NPC in the party, and many groups make that fairly impossible.

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I've done this! It's super fun! You really need player buy-in for best results, and it helps to know and trust your group. But I've done it two different ways. The first might work best for a "surprise everyone"

Everyone Gets A Note
This is useful for many situations besides this specific question. Pass a note to each player. All but one of the notes will say something like "Don't tell the others this note doesn't say anything." Heck, sometimes ALL the notes would say that. Just to keep 'em guessing. But sometimes one note would say more.

To maintain the level of surprise you're looking for, the notes would have to be pretty subtle. I've done this to start with, but I'll admit I never maintained it all the way through for that one player. "For some reason, you're really curious about Project X." "For some reason, you really want to get your hands on that map Bob found." If you want to provide clues, you can do that in notes to others. But if the master spy is a real master, you probably don't want too many of those.

That said, I think getting the player in on the gag is a better way to go. In the specific instance of replacing a PC, you can give a player a note which reads, "You are now a spy disguised as your PC. Act normal until further notice."

I used this in my pulpy horror game when a PC was replaced by a shifter. Notes began as "There's nothing happening here and you want to go home." Later they were "You have a bad feeling about anyone going near the shed." And finally admitting to the player, "You're the shifter. Convince the others to go home without alerting them, or attack them."

When the player announced he was attacking another PC, it was an awesome moment of "WTF?!?!" Then when the shifter reverted to his natural shape, I took over and told the player "You wake up locked in the shed," it was awesome fun.

Swap Character Sheets
I used this method in a convention game with pre-gen characters, and I've used it with my regular group. Just make a character sheet and when the time is right, swap it out. There are several ways to do this without alerting the group:

• Ask for the sheet and pretend to copy down a note. Hand back a different sheet. I did this in the convention game four times without getting caught.
• Swap sheets during a smoke/restroom break.
• Some GMs keep character sheets for Players. That's super easy. In my group, I gave players cheap folders with their characters which I collected after sessions. They were used to getting them back with notes, extra XP, etc. One week I just gave a player a different sheet entirely.

You don't have to do the sheet swap or note passing at the exact same time as the in-game swap, either. When I did the sheet swap for my group, I did it between weeks, and the new sheet had a note letting the player know the moment during last week's session the switch happened. "Remember last week when you fell into the water and the others hauled you out? Well... it wasn't you they hauled out."

I've used both of these and they work. The note passing method is better for a game where you want players on edge. Always passing notes will put many players on a sort of general alert. This is great in some games where you want them looking over their shoulders.

The swapping method provides a more subtle transition without getting the party on edge, which often makes the reveal that much more satisfying. But it also needs the most buy-in. It's also SUPER fun to do it the spy doesn't have the same skill set as the character he's replacing. Although that won't work well for a long term swap, it's great for a short term swap. "It's an ogre! Bob, fireball!" "Er.... I didn't have a chance to study my books this morning. Sorry."

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+1 I'm definitely glad I kept reading past all the higher-voted answers from the first 12 hours after this question was asked, because this late answer is a real gem! I'm definitely going to use both of these techniques. – Dan Henderson Mar 1 at 23:57

The only way I can think of doing this without alerting any of the players is to only use the Master Spy in sessions where a player is absent. At that moment, the spy has seized an opportunity to stand in for someone for a while, and nobody's the wiser for it. Unless you do something completely mean to the party (see my question Is it OK to Sic Assassins on my PCs?) which can have some complexity, all that matters is that you make some rolls behind the screen to see if you should hint the party that Carol's just not herself lately.

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Could help if you have that player agree/accept (in front of the others) for you to roleplay his character as if it were an NPC (you could argue that you'll need all the party present for the next session's encounters). – Roflo Apr 7 '13 at 3:10
In my groups, that agreement is implicit. – CatLord Apr 7 '13 at 11:38
Yup, in mine too.. – Roflo Apr 7 '13 at 15:07

In one D&D campaign I was in, there was one scenario where the party was slowly being replaced with doppelgangers (not too far removed from your master spy). This happened intermittently throughout the session, and so occasionally he'd pass a note to one of the players. Each note either had suggestion for a behavioral change, or something the PC had noticed like "Adrian has been acting weird, you might want to keep an eye on him." Several people got multiple notes, and since everyone was getting them, and they were innocuous until you became a doppelganger most of us didn't think much of it.

Eventually most of the part had been swapped, one of us who wasn't a doppelganger figured it out, snuck off and found where the rest of the party was and rescued them...

Regardless, if you are in the habit of passing notes to the party, especially notes that are sometimes worth sharing, sometimes not, it shouldn't be too hard get your party member who's been abducted clued in. Assuming of course they are willing to get on board ... of course, if you have time to talk to your player before hand, a little collaboration could make it much more interesting and fun. Imagine your player pretending to be their PC ... but also intentionally not getting it exactly right... the other players probably won't notice, but they'll remember it in hindsight. Yeah, the player in question won't get the "surprise" but they'll get the joy of helping pull the wool over the rest of the PCs eyes, and that can make the whole thing a lot more entertaining all around.

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I think the execution of this DM "legerdemain" could be dangerous but impressive if executed properly. I can't really think of a way to get this to work without at least some player buy-in, but there's nothing that says the player needs to know exactly what is going on when he or she "buys in."

If this was my idea, I would try to break it into a couple of steps. One, an act of kidnapping that is clearly within the player's control to stop and "remember" at a later point. For instance, a heavy drinking (drugged) session at a bar with an attractive member of that player's preferred sex, leaving them waking up in bed without their clothes and a "love note" for them to read privately the next morning. Alternately, perhaps they are having new clothes made for them by a local tailor. They are asked to try on the clothes in a small wooden cubicle where an as yet undiscovered bout of claustrophobia in the strange-smelling cubicle causes them to panic and momentarily "black out", waking with their new clothes on (with a private note in the pocket). Their former clothes are missing, "accidentally" disposed of by the tailor's apprentice in distaste of their roadworn appearance.

Then, I would have the note reveal that, in the interest of progressing the plot, the DM is willing to offer a substantial XP bonus to the character if they are, no questions asked, able to get their fellow PCs to discuss the following points in your presence before being asked and successfully rolling a certain DC dice roll ... (include list of info the spy is looking for here).

Then just let the plot progress as it will. I wouldn't railroad the plot any more than this, but it's my best guess at how you could get at what you're aiming for.

Have the player roll some sort of save or skill (escape artist) checks on a semi-frequent basis to see if their kidnapped character manages to escape. This can act as the timing device for their spying task. When their dice roll succeeds, their XP mission is over, or the spymaster succeeds in his task.

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The ideas are rolling in my head as well, I love this twist! I have two possible scenarios where all players could be surprised. Like the other answers suggest, YMMV with player reactions. Some may hate it, some may love it.

1. Take a look at the plot of The Impostor (there is also a 1984 version). Synopsis: The entire party is clued in very early that something is wrong, because the local government is convinced that 1 member of the party is a spy/saboteur/public enemy no.1. The party can then try to work and clear the character's name, only to reveal at the end that the character in question was indeed the spy all along, he/she just didn't know it. (Brainwashed/Amnesia) This is also similar to the plot of the first Resident Evil. To assuage tensions from your players not knowing their own motivations, simply allow the characters to do what they want - the setup (and the master spy's switch) is simply background. They can choose their own destiny after the reveal.

2. Consider splitting the timeline. This is uniquely powerful, because you can deliver an Alien vs. Predator (the pc game) story effect - each party member or each sub-group discovers parts of the story that the other players have already affected at different times (very spooky when you realize afterwards you were in the room just a second before or after some major plot device happened).

Analogs to method 2 include the novel Bleak Seasons by Glen Cook, and the movie Memento (which essentially tells the story from end to beginning).

Splitting the timeline is difficult to pull off and requires good planning. I think the best way to do it is to keep your story model un-restrictive: allow more than one outcome for each encounter, and adjust the rest accordingly. I often find a flowchart of encounters works well for this situation.

Also, it occurs to me the method 2 maybe a good fit for Microscope, which sounds awesome, though I haven't played it myself.

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How I would do it.

This spy, s/he has something she wants. Some information to get, some place to get the players in, some reasons to behave is some specific way that might tip the other characters and players.
Now, if this is asking them something the character the spy camouflages at, it's tricky. There's no way I can see telling that player to ask the questions without getting him in the plan.
If it's not, you could just trick the player into roleplaying the impersonator instead. First of all, you need to have him buy in the spy mission. An impersonator usually needs to be very secretive and never tell his real reasons to them. He will usually have a cover story, a fake reason he uses to guide the party to do his biddings.
Have the player buy in this reason, telling him what happens while the other players are not there.
If you want the impersonator to be the kind of guy who just tries to be the impersonated character and casually drive the other characters where he needs to, feign giving the character a very secret mission, where he needs to drive the party but never having them realize. You need to buy in the player on this.

Most of all, I urge you to think of real reasons why this tied-up character is in a room the characters actually need to pass by. Spies don't just tie him up, then let the party go that way.
Find a way for the character to escape and to stumble upon the party himself. If you find an elegant way to roleplay his escape with him without giving your surprise away, all the better. (Dreams he doesn't remember next morning, maybe. "You wake up in a dark room, remembering nothing of the past few days." Starting your tale when the party goes to sleep and stopping right before a place the party is going to be guided by the impostor.)

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One thing that hasn't been covered is the possibility of the master spy being able to enter and live in the mind of a player. This way, the player is still the same but his/her actions can be influenced or even initiated by the mind controller. Hand out notes that influence the behavior of the character and let things unfold from there.

The plus side of this approach is that the player still retains most control over his/her character.

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I suggest a rather different tack. Instead of cluing the player in on the fact that he has been replaced, keep that information a surprise until the very end. A master spy would, of course, know everything about the person he is going to impersonate. As such, the player himself will convincingly play his own character without ever needing prompting. The things the spy does in secret can be revealed later, or to other players. If the player doesn't notice, then the spy wouldn't either. And if it came to it, the player suspected of being a spy will, of course, protest his innocence. Just like the master spy would.

The twist comes just before the "real" player is found - the GM takes the player off to the side, and/or hands him a note explaining what actually happened. That way, not only is the party taken by surprise, the player himself is taken by surprise - which, of course, a master spy would be able to mimic perfectly. Ah, the delicious paranoia! What if you are the spy? Never mind your teammates - can you trust yourself?

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Actually - this would be how I replaced the character with a Master Spy. Along with an accomplice - magic-user of some sort to cast 'charm person' or similar magic on the one to be replaced. Use notecards to send to the player to let them know they don't want to go towards that closet. Try to keep the party from opening the closet.

Then, when the closet is opened, a targeted 'fear' effect would get him running.

Bam. The party turns on their own, subdues him, and 'frees' the Master Spy in the closet.

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