Pretty sure this is happening in my game

This happened in my game. I spoke with the player about having his character swapped with another version of him from an alternate universe, and he was down for it. Then it happened in game. None of the players realized it. This went on for years (literal real time years) before he betrayed them. It was delicious.

Having the traitor in the party, has a binary result, it'es either one of the best campaign you'll play, or a horror story, no middle ground

Ah man did this just spoil The Good Place for me?

What's funnier is when everyone already knows you're playing an evil character, but all their attempts to prove it in-game, even through meta-gaming, fail because the dice are on my side (evil). The best was when the DM just gave me an ability to straight up magically kill 1 person a day with a touch attack and I killed the main quest giver. Just to test it out. I was all alone with him and through my extremely high skills of deception and persuasion--and the paladin's shitty dice rolls--I convinced the party they died of a heart attack.

Got betrayed in a Forgotten Realms game by a guy who'd been playing his own doppleganger for nearly two months.

He scorching ray'd me in the back, then yelled at me for missing all the obvious clues. It hurt twice.

stamets@lemmy.dbzer0.com I was going to do this to my table. We only have 2 PCs currently (my wife and stepson), so I gave them a GMPC guide who was supposed to be the BBEG in disguise.

But they came to love the GMPC, and I can't do that to them, so now he's just their pet human.

This is sort of the case with my game. After 4 years, I just revealed to the party that the ‘big bad’ villain is actually my childhood friend and that she may not be as much of a threat as she’s letting on. I don’t actually know who the real villain is.

I remember a one-shot that had a twist like that - followed by the twist of the recently disarmed fighter removing his armored gauntlets, pointing at the traitor, and casting the system's equivalent of Magic Missile. As he pulled his magic sheet out of his pocket he explained that he'd just been a misleadingly strong and well-armored wizard all along but hadn't told anyone but the GM.

That was a fun little moment.

The big problem with twists like these...

If you know they're coming, it sort of ruins the surprise. If the GM asks if it's okay to have party betrayal (or if someone else asks and the GM says yes) then you're constantly on the lookout for it - because why would they ask if it was irrelevant? Of course, nothing says the GM can't ask an irrelevant question in the same manner they keep irrelevant minis next to their screen, but it's something that's usually frowned upon (what amounts to non-consensual PVP), so if it's known to be ok, you'll be looking out for it and then the twist won't stick.

Of course, if you don't know it's coming, then it's never a place your brain will go. You aren't just going to accuse a character (and thus player) of working against the party because that's a heavy accusation. It carries a lot of weight behind it since you're only a few steps down from calling someone a problem player. Players often don't have a good enough grasp on other players' characters to notice behavioral shifts, and players often don't have good enough acting skills to roleplay them correctly.

I've yet to hear a story where someone figured this kind of twist out before the reveal, and that doesn't surprise me at all.

I had to play my own evil doppelganger in my DM's campaign.

My character got kidnapped and got replaced by a copy, which was there to spy on the party (the DM only gave me enough info to work with at the beginning). I was given some powers which my character didn't have and started to abuse them. The DM specifically allowed for infinite uses of "Detect Thoughts" (lvl 2 spell, which I only had three uses at level 6), which I put to maximum use, on every NPC encounter the party had.

It seemed that none of the other players noticed, so I started putting on more chaos and evil in "chaotic evil doppelganger". I started having them act in a more sadistic and erratic manner, but still no effect.

I started asking other players (out of the game) what if there were an impostor in the party, but not much response. The only halfway decent response I got is a "who cares, if they're helping the party, it shouldn't matter." I gave up at that point. My character, and the one the doppelganger is a copy of, is the party healer.

I got used to playing him normally (me, the player handling the doppelganger as if it were the original, just with more powers, and a slight personality alteration) until the DM informed me that it's time to pull off the reveal.

I was caught by surprise, but I knew I had to do my part.

After what was supposed to be the boss battle, the DM gave me the signal and I said "It's been fun, guys, it really was, but unfortunately..."

The rest of the party was alarmed, and the DM had me fight the party, with monsters coming to my aid. Now, the party's out of a healer, and had to fight a horde of monsters.

Some of the other player characters (based on their characterization) were reluctant to fight my doppleganger, but I tried my best to goad them into fighting.

My character isn't the best fighter, but I did an effort. I knew the party's weakest link (my original character) but also, how the glass cannons worked. So I started directing the monsters to target them first. It was a close fight, but teetering on a TPK. The DM then introduced my original character (controlled by the DM temporarily) who swopped in to save the day.

There were lots of swearing after the DM ended the session that day.

... Because it's you, isn't it.

Everyone thinks this is me in my game for many totally legit reasons but it's definitely not. I just enjoy making them think it's me