Travance, we have learned a lot about the doppelganger problem since my first missive a few weeks ago. Hopefully this one will tell you most of the things you need to know to not get copied. If you only have time for the highlights, read the What They Are and What To Do sections.
That last paragraph makes me seem like I'm some sort of authority figure. I'm not. I'm not important. I'm just the person who's writing everything down. Anyway.
First, a critical update to my earlier missive: the technique of using psionics to look through a doppelganger’s memories and identify it that way has not yet been successfully replicated, so we should take this off the table as a viable strategy. From all of our observations and experience, it seems that the doppelgangers genuinely think they are their victims. They don’t realize they’re copies. ((OOG: we got a clarification from Matt retconning an error from the January event.))
Now, a revised edition with more complete information. This is a condensed version of what we know; more details can be found in the appendices referenced at the end of this document. ((OOG: Matt hosted a Q&A session for anyone who had questions or had petitioned him for info. I’ll link the notes people took during that session in the first comment on this post.))
A disclaimer at the top: all of this information is from observed behavior and personal experience, but it does not represent the entire realm of possibility. It's likely this is not the only way the doppelgangers act, just the way we've seen so far. I will try to keep this updated as we learn more.
WHAT THEY ARE
We have confirmed that doppelgangers are a mutation of the aberrant Arkanites Travance fought in years past. Changes in the Weave have resulted in rapid mutations of these creatures, resulting in the ones we are dealing with now. They are not constructs or Homunculi, they are aberrations.
In their ‘raw’ forms (before they have copied someone), they are humanoid shaped, but they look wrong. Pale gray skin, joints that bend the wrong way, limbs that seem too long, and they’re unnaturally tall. Nothing where the eyes or mouth should be, slits for nostrils. They don't speak and they don't use telepathy to communicate (so far).
Once they have copied someone, they are physically and spiritually indistinguishable from their victim, with all the victim’s memories, skills, combat abilities, and magical powers. They even have the ability to mimic the abilities of dragoons and holy people, though we don’t know yet whether they are merely mimicking the ability or actually copying the victim's connection to an extraplanar being.
Even their soul looks the same as their victim’s. When Speak With Dead was cast on a dead doppelganger, some answers came from the doppelganger and some from their victim. (Ask me how I know this.)
The only differences are that their bodies are hardier, and that they will unwittingly snap into ‘capture mode’ under the right circumstances. Details below.
HOW THEY OPERATE
Doppelgangers who have assumed a form act exactly as their victims would. They can and will do anything their victim would do, even if it’s working against the doppelgangers. They fully believe they are their victim. Even when confronted with the sleeping body of their victim, they do not realize they are a copy. They try to rationalize that they are the original and the sleeping body is the copy. (Again, ask me how I know this… oh, fine, I’ll just put what I remember in the appendix.)
An involuntary change occurs when a doppelganger is alone with someone who is not a doppelganger. This includes if everyone in a room is a doppelganger except one person. The doppelganger stops abruptly, their eyes glaze over, and the potential victim starts to hear static.
The static does two things, from what we’ve seen so far.
First, it puts the potential victim to sleep. This sleep can be resisted with tremendous force of will. The static is inside your head, so covering your ears won’t help.
Second, it calls raw doppelgangers to their location, who will try to copy the victim and (presumably) take the victim’s body to hide it somewhere.
If anything interrupts this, if more people arrive, the static stops and the doppelganger snaps back into their normal self. They are completely unaware that they just became a beacon.
The physical transformation takes but a moment. They also replicate the victim's clothing and equipment.
Once they physically transform into their victim, they go about their day as their victim would. As a species, their motivations are simple: capture, replace, live. They want to spread their kind and live out their lives - your lives. They think they can live your life better than you can. For a moment it may seem like you can empathize with them, but remember these are still aberrations. They are an invasive species. They have no sympathy, they cannot be reasoned with, we cannot reach a compromise.
WHAT THEIR LIMITATIONS ARE
A doppelganger can only copy once. Once they’ve chosen a victim, that’s it. That’s the life they’re committing to. This is why they’re targeting nobles and not farmers.
In every case we’ve seen so far, the victim’s sleeping body has been hidden somewhere safe and nearby. You won’t find victims out in the woods or in dangerous places.
Raw doppelgangers act like an infection. They can coordinate, they can size up a crowd, and they will leave a fight if they think they won’t win, but they won’t negotiate with you.
It seems the ‘capture mode’ in transformed doppelgangers only kicks in if the victim is the only non-doppelganger in the room, but we don't know for sure.
We have never seen a doppelganger and their victim both awake at the same time.
A doppelganger who has copied someone has all the strengths and weaknesses of their victim, so you’d kill them the same way you’d kill their victim.
There is apparently a machine that can identify a doppelganger and find their victim’s body. Very little is known about it, but Travancians are searching for it.
HOW TO DEFEAT THEM
I cannot stress this enough: find the sleeping victim’s body first. It’s the only way to know for sure that the person walking around is their doppelganger.
The victim can only be woken once their doppelganger has been killed.
Doppelganger bodies are hardier and they have the extra ‘capture mode’ ability, but otherwise you can kill a doppelganger the same way you’d kill their victim.
You cannot convince them that they’re a copy. Our brains have the fascinating ability to rationalize just about anything, including seeing a copy of yourself sleeping in front of you.
Victims usually need assistance waking up, as the sleep is much deeper than normal sleep. Smelling salts have worked well so far.
WHAT TO DO
We are safest in large numbers. Even if there are multiple doppelgangers in your group, they won’t go into capture mode unless you’re alone with them. More people in the room = less chance of that happening = fewer people get got.
Travel in as large a group as you can. They attack in groups, but they only attack if they think they can overpower you.
Use the buddy system. Form pairs or trios for the feast weekend and don’t let each other out of your sight. Don’t be alone with anyone if you don’t know where they’ve been.
Check on your friends if you haven’t seen them in a while. Be proactive.
If you see raw doppelgangers or you start hearing static, do not fight. Just run. Don’t look them in the eyes, and don’t let them touch you. Resist the sleep if you can. Run to populated areas.
If you see raw doppelgangers standing in the distance just watching, report it. Even if they don’t attack, it’s worth knowing where they’ve been.
If you find someone asleep who can’t be shaken awake, move their body to a secure location and alert someone you trust to search for their doppelganger.
If you think someone is a doppelganger, don’t just attack them. That’s illegal and also frowned upon, and they won’t know why you’re doing it. Find their body first, get a witness, prove that they aren’t a Travancian.
If you’ve read this far, I’m sincerely grateful, and you’ve just armed yourself with knowledge that will (hopefully) decrease your chances of getting doppelganged. If you have any questions or want to brainstorm, I’ll be around this weekend. I'm the tall elf in the evergreen flower crown. - Mina