Discord: A guest DM?
DM: Well, more like a co-DM… slash competitive antagonistic DM.
Discord: I like it, I like it! But I must ask: Why do you feel the need to bring ME in? The Elusive plotline paid off without a hitch. You've proven you can roll with this party's punches. Why not do that again?
DM: <sigh> Well… I wouldn't say I'm "bitter," per se, that the original Nightmare Moon campaign was utterly derailed… However… And maybe it's petty of me, but… I want to introduce a threat to the party and really make it stick, really give them a challenge worthy of an entire campaign's effort. The Thieves Guild rose up from the background and more harassed the party than anything. I want a villain again.
Discord: And, what, you're worried you might be too much of a pushover to deliver?
DM: More like… I'm not sure my DM toolkit has all the right elements. With this party, evil isn't enough. I need cunning, deviousness… ruthlessness.
Discord: Well then, my old friend… You've come to the right place.
Also, I really like the idea of two DMs. I already played in some tables with that setting, and it's always nice when both DMs just get so in synch with what they're doing.
This is going to be good.
I once attempted to start a campaign where a fellow player and I were going to switch GM duties. We created a nation that was separated into two states. which ever state the PCs wandered into was what determined which of us were going to GM that session. We designed plots that gave opportunities to ping-pong back and forth between lands. Didn't come to fruition unfortunately. The idea is still in my head though. Maybe someday.
My favorite session of all time was one where we each had 1 hour to be the GM before passing it to the next person. There were only three of us (controlling two characters each) and it was delightfully gonzo, but resulted in some of the best stories years down the road (I still fondly remember the Dueling Banjos +5 that ended up in our loot stash).
"Though I'm not clear on how this is two GMs rather than a player for the arc villain."
Probably because the guest GM gets to describe things happening to the world at large without having to roll for it and/or run it by the normal GM first. The normal GM handles NPCs, lore questions, oddball power interactions, etc.
The second GM is basically a player for the arc villain...but one who has access to most-to-all of the GM's notes, and generally works more with then GM than as an independent player. So from a certain point of view, it is more accurate to think of this person more as a GM than as a player.
Or perhaps NS is referencing both, so that the one who plays Discord can later become more integrated with the party? If so, I wonder what other good color-match alternates there are?
That's part of Discord's plan! He made his yellow too orange so as to set off readers of the comic into a chaotic argument over the color definitions of his base model.
Since we can't actually hear the people, and this could be an alternate universe, you may continue believing this. (Unless the person is "really" more like Sunset Shimmer, as noted above.)
The first arc of my Genius: the Transgression campaign ran like this. One of the people I wanted to play couldn't make the commitment, so I offered him the villain role and an approximate 200 XP budget (if you're unfamiliar with that edition of World of Darkness, 200 XP is somewhere between high level player and god tier; a generous GM gives you about 3 or 4 per session.)
So Sir Doctor Eli Roth, immortal knight of the crusades, scholar, and head of the Illuminati was born. His inventions included the holy grail (the source of his immortality) a time machine so that he could compete with the players' ability to travel through time, a continent-spanning mind control device on the Eifel Tower (charge time to activate: 100 years), and the great starship Titanic. Yes, that Titanic. It sank so that it could properly dock with its underwater launch bay. Shame about the civilians. Their final confrontation with him was in the far future on New Atlantis. An underwater city acting as the seat of government for his empire on Mars.
Having someone other than the GM controlling the villain does seem like it'd lead to some interesting scenarios.
The GM only needs to decide how the world reacts to the actions of the villain and GM, which... might lead to a more authentic experience? Or something like that. I know what I mean, just not how to say it.
I've had multiple GMs in a campaign, but usually it was them legitimately switching off because the campaign was *really long* and the original GM needed a break. Their PCs would become GMPCs and vice versa with the old GM, but they'd stay with the party.
...this is giving me flashbacks to an old Knights of the Dinnertable comic where a guest dm was brought in to play a Chaotic Evil sentient sword named 'Carvin' Marvin'
I liked to mix things up between seasons of our superhero campaign, just so I could focus on the writing the next season, so I made "webisodes", since the characters were in crygenics, I could always explain some of theme away as non-canon if I didn't like how it panned out.
I gave each player outlines for an episode, usually not more than a setting description, one or two tv/movie trailers to get them in the right mindset and 1-2 crucial informations/scenes that had to happen.
I ended the webisodes with a final session that brought all the hints I had them drop together for finale that tied all of them in to a cohesive story and linked them back in to the campaign.
The players effectively documented how the world went down the drain for the year the characters were in cryo. It was damn awesome.
In which we meet a new character and get a sense of how this thing is going to go down.