5 Tips For Co-GMing Games

Roleplaying Tips Newsletter #0273

5 Tips For Co-GMing Games

The most common co-GMing arrangement is for two game masters to sit behind the screen at once to help each other run sessions.

There are many benefits to this approach, such as shared planning and preparation, a higher GM-per-player ratio to better serve players, shared workload, and two minds to help keep games moving along.

While co-GMing might seem like a great solution to the overworked or busy game master, it tends to be an unstable group format, causing short campaigns, group conflicts, and on rare occasions, broken friendships.

Co- GMing is just like a business partnership (partnerships have the highest biz mortality rate in North America of all business types), and should be considered carefully.

Here are some tips to help you get the most game value, longevity, and fun from your co-GMing endeavours.

Designate The Primary

Despite calling it co-GMing, there should be a primary GM and a secondary GM. The primary cannot be overruled when he makes a final decision and is responsible for ensuring games happen and are fun for all. The secondary GM can have an equal role and status in the game, but between you, one must have the final call and ensure good games happen.

A key shortfall of co-GMing is the communication barrier. When a single GM runs a game, metagame and GM thinking occurs seamlessly inside one brain. When a second game master enters the picture, there now needs to be a great deal of ongoing communication between GMs ranging from setting details to plot arcs to encounter tactics.

Many times, important tasks and decisions accidentally remain undone because each GM thinks the other has them covered. Therefore, one GM needs to ensure that game dates are set and met, organization is good, and the group is satisfied with gameplay.

Arguments between GMs is another critical downfall. As GM- role communication increases because there are more brains involved, so too will differences in opinion and style. Strife can arise from a number of sources, just like in any other relationship. In my experience, major points of pain have been:

  • Plot line and story line (“A war between elves and dwarves!” “No! A world-quest for a magic item!”)
  • Boredom (one GM gets stuck with the unpopular tasks)
  • Equal participation (one GM serves drinks the whole night and gets no opportunity to do much else)
  • Rules interpretation
  • Players working one GM against the other
  • Agreements get broken (usually from necessity due to character actions)

Designate a primary GM to make final calls on contentious game issues so disagreements are settled quickly and with authority (players cringe when GMs argue, a decision feels tentative, or one GM overrules another later on). The secondary GM must agree and accept that they’ll be overruled, are not to argue, and to let play continue with minimal interruption during the game. This arrangement requires ongoing compromise by the secondary.

It also requires empathy from the primary. The primary must try to respect the feelings of the secondary by being professional, firm, confident, and polite. The players at the table form an audience, and it’s hard on the ego to get overruled publicly.

A primary-secondary relationship keeps the game moving as well. I found when co-GMing that conferences between game masters (whispers behind the screen and meetings away from the table) would get out of hand if one GM didn’t have the authority to end discussion with a decision. Meetings will be unavoidable, but they can become frequent and long if there isn’t a primary.

Finally, two GMs with equal power creates another critical dependency for games to happen, and you want to reduce dependencies as much as possible for easier scheduling and fewer cancelled sessions. If both GMs must be present at every game, then that’s one more reason why games might not happen. A primary-secondary set-up can make it easier for the secondary GM to miss the occasional session, letting the game go on.

It’s possible to establish primary-secondary in different categories of GMing tasks (see the Create GM Portfolios tip in this issue) if that works better for you. One GM might have the final responsibility and decision-making power for combat, NPCs, and game days, while the other has it for plot line, rules, and world details. Note this increases the dependency requirement that both GMs must be present at sessions.

There might be a great spirit of cooperation between GMs, but ultimately one must be responsible. Unless you have ESP, you’ll either need to meet frequently in-game to strategize and discuss consequences to PC actions, or you let the primary make the call. It’s a bit like improv–everyone loses if two players with different ideas try to pull things in their direction.

Create GM Portfolios

Fortunately, GMing involves a number of ongoing tasks that can be worked on independently by each GM to share the workload and raise the bar on the GM-role. It’s good for two busy people to help each other out, and it’s wonderful if the overall player experience improves each session because of the presence of two game masters.

Here are some example portfolios:


  • Game world design (deities, history, nations, and so on) (Note: world design is such a huge task it can be divided into numerous portfolios as well if bother GMs are inclined)
  • Plot design
  • City, town, village design
  • Dungeon design
  • NPC design
  • Monster design


  • Running/designing wilderness encounters
  • Running/designing civilized encounters
  • Running/designing dungeon encounters
  • Storyteller/narrator and descriptions

Combats & Roleplaying

  • Running combats
  • Running combatants
  • Roleplaying NPCs and monsters


  • Rules champion (interpretation, knowledge, house rules)
  • Rules documentation

Session Management

  • Session physical organization & hosting
  • Session planning (encounters, events, and so on)
  • Handling EXPs and rewards (in a context of managing game balance)

Mapping & Props

  • Creating maps
  • In-game mapping
  • Creating props and player handouts

The primary responsibility of each portfolio is to ensure it gets done well and on time. It’s viable to collaborate on and share tasks within portfolios (such as encounter idea generation, encounter design, encounter documentation) as long as the portfolio gets the attention it deserves as per the style and preferences of everyone in the group.

Dividing and conquering using portfolios also lets both GMs work to each others’ strengths. Some people are better at some things, such as stat block generation, writing backgrounds, being organized, storytelling, and so on. If each GM does what they do best, game quality should increase as well as GM enjoyment.

If there’s a conflict over portfolios and tasks, one suggestion is to use a Draft Selection method. Each of you chooses what you want to take on until you are left with tasks you both want to do and things neither of you wants to do. Next, decide who picks first (dice roll, rock-scissors- paper then take turns choosing until everything has been allocated.

Portfolios also let co-GMs estimate and manage workloads. I recommend making a list of portfolios and tasks for your game, then figuring out the workload each GM is willing to take on (best expressed in terms of hours per week). Assign/choose portfolios and tasks. Determine if there are any commitment discrepancies. You want to look out for a GM being overloaded or in a position where they don’t have enough time to complete their assigned portfolios.

Understand that time requirements for each portfolio grow and shrink, so perform workload assessments often, ideally between each session. For example, one GM might design and flesh out the PCs’ home base, taking care of the world design component for the next few sessions, or one GM might have to design an encounter with 20 important NPCs for Tuesday night.

The end goal is to ensure that minimum preparation requirements are met for each session, and ideally, preparation is done much better than what a single GM could manage because of the divide and conquer approach. In addition, in-game GMing should be smoother because the GM role gets two brains, four eyes, and two sets of hands with minimal collisions.

Note that portfolios need not be split 50/50. One GM might want to contribute by running foes in combats and taking session notes. Great! If this works for both of you, then you’ll happy and the campaign becomes better from your cooperation and joint dedication.

Split Party GMing

Split parties are often headaches but this is an area where well coordinated co-GMs can excel. If the PCs split up, it’s possible for each game master to GM a split portion. This saves a lot of game time, prevents idleness, and results in greater player freedom and character choice. If split parties work well for you, then you might even consider designing more divided group gameplay as a GMing and campaign strategy.

Some Split Party Co-GM Tips

When the party splits, one GM should take his mini-group to another room and game there. This helps prevent metagaming from players who would otherwise know what went on with the group their PC wasn’t a part of, it adds an element of the unknown and surprise, and provides an opportunity for players to roleplay a recounting of events to the group (characters _and_ players will only know what they are told).

Prepare an alternate game room or area before the session starts to minimize disruption of gamers and non-gamers.

GMs should meet after the party joins up again to compare notes to synch up.

For long splits, GMs should meet often to provide updates. You want to avoid logic errors where the actions of one party could impact the other but go unnoticed or unreported. Every ten minutes is a good rule of thumb, unless there’s combat involved, in which case you can meet after the combat finishes. Important things to compare notes on are:

  • Timeline. Avoid letting one party get too far ahead in time unless you both foresee no problems.
  • Location. It would be disastrous if PCs from each party end up occupying the same space without noticing each other.
  • Story. Word can travel fast. Do events with one party impact the other? For example, a fireball in the middle of town might be felt or reported to the other party.
  • NPCs. (Most) NPCs can’t be in two places at once.

If at any time one GM feels it important to coordinate, then a brief meeting should be called.

If you both feel comfortable with split parties, figure out how you can use this event to benefit gameplay. For example, if one PC splits off, is taken to another game room, and then gets charmed, fun gameplay will emerge after the group is united and the character starts acting unexpectedly. Another example is where PCs have different and conflicting goals. A final example would be narrating the consequences of character actions without players knowing if the consequences were caused by their fellow PCs or others.

Decision Through Opinion

With co-GMing, it’s effective to make decisions by gathering opinions first. This creates a game table environment of fairness, encourages player contribution, and taps into the thinking of several individuals at once for better-informed judgements. Another aspect is that it allows free communication between GMs at the game table without requiring painful gameplay pauses while GMs confer.

Some situations will require private GM talks, which is fine, but open discussion is preferable when secrecy isn’t needed. By adopting a group opinion style, you minimize boring GM-to-GM only discussions, which I’ve found frustrate players if frequent.

It’s also important to reveal the 4th wall only when necessary. In general, the 4th wall in RPGs is out of character (OOC) talk, such as rules discussion. Co-GMing risks to worst kind of OOC chatter: GMing tactics, metagame information, NPC abilities, and anything else that would normally ping around the head of a game master in single GM games.

For example:

GM1: “Ok, roll initiative everyone.”
GM2: “The troll gets 14.”
GM1: “Does that include the troll’s improved initiative ability?”
GM2: “Yup.”
GM1: “And the troll’s boots of speed or amulet of dexterity?”
GM2: “Ahhhhh, yeah….”

When co-GMing, know when it’s ok to reveal the 4th wall to minimize GM conferences and keep gameplay running along, and when to pull back and discuss things privately.

A good way to get opinions is to go around the game table and ask each gamer for them, including the second GM. If players have no opinion, they can pass or wave and you move quickly on. This ensures loud and aggressive players don’t dominate, reminds you to ask quiet players, and includes the second GM whom you will tend to overlook.

Agree On A Campaign Vision

Establish a clear vision of the campaign, including tone, style, priorities (such as player fun), and core plot threads. Conflicts will arise between co-GMs, have no doubt. Depending on the personalities involved, some conflicts will be more heated than others. Regardless, each conflict represents a potential campaign breakdown, gameplay delay, and potential interpersonal conflict.

For example:

GM1:”Rothgar looks at each of you and decides to come clean. He begins to tell you a story of deceit and betrayal…”
M2: “Wait a minute! Rothgar would never cop to the PCs– he’d go down fighting.”
GM1:”Well, I think he’d choose to talk rather than get killed.”
GM2: “I don’t…”

Another example might be a conflict during plot design. GM1 wants to include elves, GM2, a Talislanta fan, wants no elves in the campaign.

One solution is to fall back on the primary-secondary relationship. The primary GM of a portfolio makes the final call. However, this doesn’t mean the secondary GM will like every decision and he could start building a grudge or resentment or enjoy the game less.

A solution to prevent this calamity is to co-develop a shared campaign vision. In sports, this is sometimes called keeping your eye on the ball. What is really important at any given time? You might decide it’s having fun, running action- filled adventures, and letting the PCs be heroes. Should a disagreement erupt, both GMs can use their shared vision as a method to align their feelings. Is it more important for an NPC to advance the plot and set-up an opportunity for a rousing fight (as per the example above), or is it better for the NPC to stay true to his design?

Shared visions also enable faster refereeing. There’s a potential need for GMs to confer every few minutes in some situations, and you want to avoid this. By following a vision, a co-GM can make a decision that follows the spirit of the vision and not get caught up in details, meetings, and worrying.

A shared vision also increases trust between GMs. One GM might be puzzled over the decision of the other, but if he has faith his friend is making a decision based on the spirit of their agreement, he’ll be satisfied to let things go and chat about it after the game.

When a conflict arises between GMs, you each need a touchstone to ground yourselves and make a joint decision, usually after compromise. Compromise is achieved by placing the game above your own personal needs and feelings during sessions.

More co-GMing Tips

Roleplaying Tips #178: Tips For Dual GMs
Roleplaying Tips #145: Co-GMing Tip: Special Effects Person
Roleplaying Tips #124: Co-GMing Tips

Tips From Roleplaying Tips Game Masters

Have a roleplaying tip you’d like to share? E-mail it to [email protected] – thanks

How To Make Prop Maps For Your Campaign

From Brant Williams

The whole reason I got into DMing was for the simple reason of wanting to make props for a campaign. I made a prop map and showed several friends. Apparently, from the quality of this map, they all assumed I was a really good DM. I had friends knocking down my door wanting to be in my campaign. Funny thing is, I made the map for fun with no intention of starting a campaign. Last night we had our 16th session.

To me, props make the game, and by props I am referring to items given to the players that look and feel like they are directly transported from the world their characters exist in. Props come in all forms: maps, sealed letters, coins, gems, and so on. Props also add to and further the realism of the game. Below is a prop-making tip for maps.

Aging a map is a very simple process. Here is how I do it.

I take a piece of regular white printer paper and lightly sketch out the landmass with a pencil. Then I go over the pencil lines with a waterproof ink pen. I find the Uniball Gel pens work great for this. Then, neatly write the names of the land masses. For people with access to a scanner, you can scan in your drawing and add land names to the map in any of the various graphics programs. Add any other little widgets or lines too. Sometimes, I add little sea monsters in the oceans from old clip art books.

After you have your nifty little map drawn or printed, boil some water. I usually get 2 medium tea bags (single serving coffee bags work too) in a coffee mug and pour hot water over the bags to fill the mug. I let the bags sit until the water cools, then I squeeze out the remainder and set the bags aside.

While the tea is cooling, fold over the edges of the paper approximately 1/8 of an inch all the way around and neatly crease them. Then tear them carefully, or not, depending on the effect you are going for. After you have torn the edges, wad the paper into a ball and flatten it back out. I run the paper over the edge of a table to get it really flat. The paper has essentially been broken so that the tea can stain the cracks in the paper. You can, if making a folding map, fold it up and make the creases according to how you want it to fold (this makes a neat crease effect after staining).

Find a flat dish. I use a Pyrex baking dish that fits the paper exactly. Place the paper in the dish facing up and pour the tea (or coffee) over the map and tilt the dish around until the map is fully covered. Drain off the excess liquid back into the coffee mug and set aside. At this point you can add effects to the stain. Sometimes I break open the tea bags and lightly sprinkle tea leaves onto the paper, or I will sprinkle salt onto the paper for unusual effects.

I then set the dish in the sun to dry. This works fairly quick. Once, before a game when people were showing up, I was in the kitchen with a blow dryer trying to get it dry. This works too, but it is really annoying.

After drying, inspect the map. If you want it darker, repeat the stain process or try it again with coffee.

Once the stain is to your liking you can age it some more. Other techniques I use to age it further are:

  • Wadding it and flattening it over again.
  • Burnishing the wrinkles out with a spoon.
  • Take a brown ink rubber stamp pad and run the edges and creases across it to darken them (my favorite).

The map is now finished, although I sometimes get a little carried away and go as far as colouring it with coloured pencils or watercolours.

Give it a try and add another dimension to your game.

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What is NERO?

From Logan Horsford and Kristopher E. David

NERO is a fantasy medieval action adventure hosted at multiple locations throughout the United States and Canada. Currently, there are over 40+ NERO International Chapters within the US and Canada and 11 NERO Alliance chapters within the US.

At every NERO event the local plot team and their cast unfold storylines designed to entertain and challenge the event participants. These storylines range from short term (one event) to long term (several years) and are directly affected by the actions of the event participants.

Foam boffer weapons and small bean-bag like packets determine the outcome of any conflict that leads to battle. Actual skill (both yours and your characters) gets used in the game as opposed to rolling dice and consulting charts. You may find yourself chasing monsters through the woods as they flee from your sword prowess, or yelling spell incants and throwing packets at their fleeing backs in the hopes to decimate them with your character’s skills in the arcane. Boffer and packet style combat is very safe and has caused less injuries than Little League Baseball.

Up to several hundred players may attend each NERO event. Both men and women enjoy the game and attend regularly. The events are held at a variety of different campsites with various accommodations. Some sites offer places to put your tent, while others offer cabins with hot showers. Many events host a tavern with great food, while others will advise you to bring your own meals. Typical events start Friday night and continue through until Sunday morning or afternoon. Events can be shorter or longer as well and will have their duration posted on your local NERO website.

When creating a character for NERO you may choose to play a human or one of eleven non-human races ranging from Elves (so common to fantasy settings) to Sarr (a catlike people). Character skills are necessary to keep the game balanced and safe. Character skills are purchased with points that are granted by attending NERO events. Obviously, the more events you attend the more your character skills can develop as you have more points to spend in purchasing character skills.

NERO characters and the treasure gained through adventures are usable in any of the NERO chapters within North America with exception to International and Alliance games; these two NERO games are separate entities and do not allow transfers from one to the other.

Thanks toDavid Bliss, Doug Fleming, Jenn, Kristopher, and Nyx for their contributions.

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Easy Floor Plans

From Scot Newbury

Don’t be caught by surprise when your group heads into a building or asks, “What does the mayor’s house look like?” There’s no need to spend hours drawing floor plans or rehashing old ones when there is a steady supply of them on the magazine rack.

While at your local bookstore picking up a copy of your favorite gaming magazine, slide down a bit to the home improvement section and pick up any of the magazines with ‘Floor Plans’ in the title and have a look. In most of these magazines, there are a host of home exterior sketches along with a description and a (typically small) floor plan guide. Pick one up and you’ll have over a hundred floor plans and numerous visual aids to boot.