I have played fantasy RPGs since 1988. In those 31 years, I cannot recall a time in which a doppelgänger infiltrated the player character's party. In our July 1st 2019 session of Tomb of Annihilation, that changed.
About 4 sessions prior, the players freed from a mirror of life trapping a cadre of non-player characters.
- A human champion of the deceased queen
- A minotaur lieutenant
- A drow wizard
- A human rogue
They already had Trevor, a human guard once employeed by the Red Wizards, working with the party. Poor Trevor died to a Bodak. And the minotaur died when the party attempted to move a statue that encased a sphere of annihilation. Alas the poor minotaur fell into the sphere.
They also allied with a twice-liberated now frustrated Dao; They had freed the Dao from a bottle but another trap ensnared it. Again the characters freed the Dao, and it joined forces.
The party also brought into their team an awakened lizard.
Based on prior information, the party suspected that somewhere in the dungeon, they might encounter a doppelgänger.
A large number of NPCs seeded an environment in which a doppelgänger could bring about some chaos. With the hook set, I waited for the moment when the doppelgänger could strike.
Moon (a PC Tabaxi ranger/rogue), Erd (a PC dwarf wizard/barbarian), and Pox (an NPC
human rogue doppelgänger) choose to explore a secret room. The dungeon then separated this small group from the larger group. In haste, the three explored the rooms beyond, finding treasure, animating guardians, and runes that radiated conjuration magic.
Seeing pending doom, the characters raced for the runes to get out. In that moment, before anyone knew what would happen, I mentally committed to having Pox take the shape of Moon. Pox knew Tlad was eager to gain control, that the Dao was angry, and Octavion may, in its blathering, draw further attention to Pox. I also considered the new trickster god inhabiting Moon—one bent on vengence against wrong-doers.
They raced to the runes. Pop. Pop. Pop. Teleportation. Better yet, they had chosen one that cast polymorph on the characters. Moon failed its save, and changed into a bat. Erd made its save. And Pox failed its save, but “[polymorph] has no effect on a shapechanger” (5E SRD).
I text Matt “You are now a bat.” Then I describe the scene: “Moon and Erd, you appear in a room of mirrors. Fluttering around is a bat. You wait but Pox does not appear.” As they consider what to do, I text Matt “You are a doppelgänger act like it.” Even before I've sent the text, Matt has stepped into the role of playing the new Moon.
Quickly, doppelgänger-Moon bags the bat. Then doppelgänger-Moon and Erd trek back to the rest of the party. We leave the session at that.
Matt and I exchange some texts, to clarify our understanding. And I proceed assuming that the party will figure it out. Polymorph lasts one hour, events will need to progress quickly before bat-Moon reverts.
At the start of the next session, the party calls for a long-rest. After some half-hearted discussion, the group sets the watches to:
- doppelgänger-Moon and Octavion (an awakened lizard)
- Erd and D'John (a Dao NPC)
- Tlad (a drow NPC) and X
- Regina and Lakuna (a human NPC)
I see Matt start to text me, and I realize I don't have my phone. So I say “Oh crap, I must've left my phone at home. I need to text Jenny to reminder her to give our dog it's medicine.” With that, we proceed with understood intentions. Throughout the remainder of the session, Matt drops very subtle hints: “I don't have any goodberries, I used all my spells for the day.” Once curious, doppelgänger-Moon becomes quite cautious; Because doppelgänger-Moon does not have Moon's preternatural senses nor perception.
With no strong preference for who takes first watch, I randomly roll. The first watch falls to doppelgänger-Moon and Octavion. I roll some dice to check for random encounters. No random encounters.
I narrate an uneventful watch for all. But off-screen during its watch, doppelgänger-Moon did the following. First, he strangles Octavion. Then grabs the bag with bat-Moon and sneaks over to the sphere of annihilation and dips the bats head into the sphere. The body reverts, doppelgänger-Moon pillages the items, and tosses tabaxi-Moon and Octavion into the sphere. He then cuts/tears a hole in the bag.
A bit of time passes before they realize Octavion is gone. The party checks with doppelgänger-Moon, and he pulls out the now empty bag with a cut in it. The party, rather confused wonder about this talking lizard and it appears they think the lizard did something and fled. I'm sure their rattling around ideas.
In our session, Matt has given an admirable performance. Matt established early in the campaign that Moon had an aversion to water: He would not get in the boot; and he would not step into shallow water. In the second session of infiltration, doppelgänger-Moon offered to explore a diving cage partially submerged in the water. He no longer offers to scout ahead. Some of this you could attribute to the influences of trickster gods, influencing most everyone.
In our session, Matt again delivered. He continues to offer to go into the water. He avoids scouting. He keeps his distance. When the party faced a complicated puzzle room, he chose to separate from the group. When, during his separation, the Dao NPC companion died, he disposed of the body.
Fourth and Fifth Sessions
In our session and session, Matt continues to make excuses about not having goodberries; “I cast all of my spells for the day.”
Matt missed our session, in which the party routed a coven of night hags.
Knowing they were drawing to a close, in our , the party sought a long rest. But Withers, the tomb custodian, had plans to disrupt their rest and prevent them from gaining access to the Soulmonger.
The party defeated Withers and company. And Regina (played by Alex) found a potent object. Before they resumed their long rest, the Barbarian Wizard cast identify to understand the amulet; It would allow one person to teleport into and out of the tomb.
I told the players to level up their characters, because they would be getting an uninterrupted long rest.
For our session, we started with a long rest and a cut scene. From an administrative stand-point, we had 40 minutes before dinner was ready. We spent that time narrating the cut scene and talking through the inevitable fallout.
X (played by Paul) you wake a bit confused. Moon should have woken you up for your watch. You see a pile of keys where Moon's bedroll should've been. Moon is gone.
Cut to an hour or so before. Moon waiting until all are asleep, quietly and delicately lifts the amulet off of Regina's person. He then packs up his things, and leaves the five keys.
Without glancing back, and quiet like a wraith, he leaves the encampment and sneaks his way through the Tomb, up towards the entrance. He takes the amulet, attunes for an hour, and poof he disappears from the tomb, leaving behind all of his possessions.
From that point forward, the party cursed Twelvevine Moonshadow, the tabaxi ranger.
It has been a great run with a doppelgänger in the party, especially since the doppelgänger needed help from the party but had a goal of getting out of the tomb.
And it was fitting that the doppelgänger betrayed the group in the penultimate session.