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Methods of Collaborative Game Mastering

This is part of a Gnome Stew double header. Click here to check out John’s article [1] for a look at collaborative GMing from a beginner’s perspective. It’s also a very belated response to AlasseMages’ suggestion in the pot.


Game Mastering can be a lot of fun, but it can also be a lot of work. Some of us simply don’t have the time or energy to devote to managing a campaign on our own. While the answer seems obvious (hand over the reins and become a player), things are not always clear-cut. Perhaps you are the only GM for the group and, without you the group dissolves. Maybe you’ve got a great idea for a new campaign that you want to see through, but your hectic schedule impedes your prep time. Maybe you want to see the current campaign continue but you need a break. Or, from John’s perspective as a player, you’re willing to step up to the GM’s chair as long as it’s a part-time position.


One issue with co-GMing is that it’s difficult to nail down a definition. “Collaborative” implies sharing, but some types of co-GMing require little in-session assistance between participants. In other cases, it’s absolutely critical for the co-GMs to work together during a session.


Another consideration is the reason why you feel that co-GMing is desirable. Certain types of co-GMing methods work better to solve certain issues than others.


Here are a few co-GMing methods that I’ve either employed or been a first-hand witness to, along with my reflections on each.



I’d venture to suspect that most of us have employed this method at least once, especially in modular class-and-level systems. Two or more GMs take turns running the group through adventures, usually changing hands at predetermined endpoints (e.g. “I’ll run the group through the Slaveport Trilogy; by then they’ll be fourth level and you can run the group through the Labyrinths of Law”).


A variant of the Tag-Team is the Side Trek, where another occasionally GM substitutes for the primary GM. These side adventures are usually self-contained.


I’ve never had a problem with tag-teaming, especially in D&D. One problem I did unfortunately sit through was a GM that didn’t take the tag-team opportunity and forced us to slog through low levels that he had no interest in running so that we could get to this awesome adventure he bought. Needless to say, we never played the adventure, since he bored us to tears long before then.


Shared World

This is another old favorite of mine. Two or more GMs design and run a campaign world. Sometimes they operate in different locations (in a Superhero game, Lucy primarily runs games in Metro City, while Miranda runs her games in North Harbor), or perhaps one GM designs the world while the other GM creates adventures for it (the designer essentially becomes the “setting lawyer”).


In shared worlds, events from one GM’s adventures may get referenced or share NPCs with the other GM’s adventures.


Shared worlds are another very comfortable type of co-GMing for me. It’s the default assumption in modern games or games with an embedded setting (such as Star Wars or Babylon 5). I remember one Delta Green campaign where my co-GM took a favorite NPC of mine and roleplayed him completely differently. When I retook the chair, I played the NPC the old way. When one of my players commented on the changes, I just shrugged and said “the original actor was unavailable for those scenes, so we had to temporarily recast him.”


Rotating Campaigns

Believe it or not, rotating games is a form of co-GMing, and one that seems to be increasingly popular amongst my graying friends. Rather than collaborate on a single campaign, two or more GMs run separate campaigns on alternating sessions.


I’ve generally had good experiences with rotating campaigns. They’re helpful to players that can’t make a commitment to every session but can join one group full-time. They also allow GMs to control their campaigns while relieving them of the burden of a weekly grind. The only problem with rotating campaigns is that scheduling issues occasionally put long stretches of time between sessions (recently I joked to a player that our biweekly (fortnightly) sessions had become monthly sessions).


The Adversary

I first learned of this while reading GURPS (under the same title). The Adversary is a GM that plays the bad guys, usually in combat situations. Theoretically, the Adversary should have no knowledge of the PC’s abilities, although in practice this will only work for the first few encounters.


The World of Darkness LARP variant of this is the Narrator. While the Storyteller has the creative control, the Narrator is empowered to play certain NPCs and adjudicate challenges.


I’ve never had much experience with this beyond allowing a player whose PC died to play a villain throughout the combat (or her own charmed/hypnotized/zombified and now adversarial PC). I suspect that this works better in small doses unless the adversary GM is given some long-term goals.


The Covert GM

The covert GM is a co-GM that pretends to be a player while she is secretly working with the GM. Sometimes this collaboration is present at the outset; other times a player becomes a covert GM due to circumstances in play. Usually, the covert GM is ultimately at odds with the PCs and her revelation leads to a climactic fight.


An alternate is the Meta-PC (ooh, I created a new term!). The meta-PC is a PC run by a rotating GM. The other players realize that the PC has meta-knowledge of the campaign but trusts the non-running GM not to abuse the privilege.


This is one of my favorite tools as a GM. I’ve often used my “Body Snatchers” card to replace a PC with an evil counterpart and let my player in on the deception. Players are usually excited to play the role. I have, however, seen this played poorly, when a co-GM forgets what his evil powers are or tips his hand too early.


Divided Party

In large groups, especially LARPs or tournaments, the PCs may be divided into several groups, each with its own GM. The individual GMs may have an overall coordinator or they may gather together from time to time to keep each other appraised of what’s happening. Alternatively, again especially in LARPs, the PCs may interact with each other and grab whatever GM happens to be walking past when they need one.


I’ve seen this work very well at GenCon, and I’ve run a LARP. The only danger that I’ve encountered in tabletop is that one group may progress too fast, leading to downtime as they wait for the other groups to catch up. In LARPS, one GM may get the reputation of being “the final authority.” Once this happens, every player will line up to engage this one GM or attempt to get her to overrule another.



Back in the 1980s, I was part of a small group in a Marvel Superheroes campaign. Every player had a character (in some cases more than one) that was part of a superteam. On any given night, we’d roleplay the group hanging around the base and dealing with personal subplots (usually, one of the other players would GM a subplot for another player). Sometimes, one player would arrive with an idea for an actual adventure and assume the GM role for the duration. At other times, we’d commiserate over what we wanted to do and then one of us would get inspired to run it.


Sandbox co-GMing works surprisingly well in dramatic campaigns that are full of subplots, especially if the PCs have defined personalities and motivations. In spite of there being GMs, sandbox co-GMing is often the default assumption of a LARP (i.e. the players make their own stories).


Wrapping it Up

Those are my experiences with co-GMing of different stripes. As you can see, there are many ways of co-GMing, some obvious and some not-so-obvious. If you have any good or bad co-GMing experiences, please feel free to share them. I’m always looking for ways to lighten the load (as well as be aware of potential pitfalls)!

8 Comments (Open | Close)

8 Comments To "Methods of Collaborative Game Mastering"

#1 Comment By Nicholas On May 22, 2009 @ 6:33 am

I’ve never thought about it before, but I guess I’m a covert DM. My girlfriend is a fairly new DM so she asks for my help while she’s planning and then during play I pretend not to know about the things I came up with. The rest of the group has no idea.

#2 Comment By John Arcadian On May 22, 2009 @ 11:31 am

Great Article! I’m definitely going to be more prepared in my “newb” attempts at collaborative GMing, and I’m going to steal the “Orignal Actor couldn’t be found” line.

#3 Comment By DrOct On May 22, 2009 @ 12:14 pm

An excellent set of articles, and quite timely, as a friend and I have been talking about collaborative gaming (both GMing and world building and other aspects) a lot lately.

Also timely as I’m about to start my first game, and we’ll be using the Rotating Campaigns model.

For a little while now we’ve been switching off about every other session between our regular D&D game and occasional True20 adventures set Manhattan in 1890. I’ll soon be taking over as the “alternate” game for a least a while as we run through a short 4E adventure I’m working up. I think our current GM is going to be pretty happy to have every other week off and to get to play as a player again!

#4 Comment By Scott Martin On May 22, 2009 @ 1:55 pm

Our group enjoys the rotating campaign model– it’s a chance to play a couple of different games. As a GM, I particularly like it for giving me a little extra prep time, or for recharging my batteries by getting to play.

Shared world can work very well– I’ve enjoyed playing and GMing in that format, though it’s been a while. I’ve been the covert GM at times, often while the “actual GM” learns the system. Though everyone enjoys a confidante…

Divided parties and shared world co-GMing are both interesting, but I’ve only encountered them rarely– particularly at cons or in Larps for divided party.

#5 Comment By MAK On May 24, 2009 @ 1:01 pm

Our current campaign is a tag-team shared world with a three-GM rotation. The same model has been used for years now and works extremely well – especially now that we have started to mix in collaborative adventure design (so there are two meta-PC’s around at all times)

We’ve also tried divided party once in a huge fight that took place bout outside and inside of a building, with one GM dealing with the outside, and other the inside. Worked OK for that session, but the situation must be such that dividing the party makes sense and polling between different groups would be too slow or reveal too much to the players whose characters are not present.

For the GM’s in our group, the collaboration pays off especially in design (as we do not use published adventures) – actual play works usually better with only one GM in charge, although the meta-PCs can point out some forgotten details if needed.

#6 Comment By Bartoneus On May 26, 2009 @ 6:04 am

My current game is a shared world with DaveTheGame’s, except his game takes place several hundred years before my game. It was one of those ideas where we though it would be really cool, but felt like we’d never get to do it so we finally just went for it. So far it’s working out really well!

#7 Comment By Leketh On May 26, 2009 @ 8:46 am

A buddy of mine and I ran a collaborative game with Burning Wheel. We started it off as two noble houses on oppisite sides of a civil war (two groups, two GM’s) with joint sessions every six weeks or so. The groups eventually (dispite our best efforts to maintain regional bias) worked together to uncover the larger threat. It was a blast.

#8 Comment By Lord Inar On May 28, 2009 @ 1:38 pm

It’s probably the simplest way, but I really like Side Trek. The non-primary GM usually chooses whether to keep their characters for the adventure or not based on their comfort level.

If I think about it, it really is the only method I’ve done, other than truly collaborative (i.e., simultaneous) GMing, where one GM runs the story and the other gets minis, prepares maps, tracks initiative, makes sure evrybody is moving along smoothly. This method is used for larger groups of players, especially kids.

#9 Pingback By Troupe Style GMing and the Gaming Charter | John Arcadian On March 20, 2015 @ 6:12 pm

[…] that time Walt and I wrote a double header about this subject, and you can find Walt’s article on Collaborative Game Mastering here while mine on how I thought it would go here. With a little experience with it under my belt, I […]