The Unconstrained GM

Imagine being able to GM on the fly with no books by your side, no prep notes, no monster manuals with pages bookmarked, and no laptop and increasingly essential (no pun intended) D&D Insider account acting as persistent distraction at the gaming table.

Imagine being able to run a successful Fourth Edition D&D session using nothing more than a single sheet of paper.

That’s how I game, and today I’m going to show you how.

The key, really, is boiling 4e down to basic numbers. A GM screen goes part of the way but tends to scatter the different level-appropriate values all over the place. I made my own one-sheet summary a while back, then shifted to using Sly Flourish’s excellent Master DM Sheet for a while as it was far superior to my own in every way.

Time passes, and I have created a fresh sheet which simplifies things further.

Here are the first three levels.

Lvl Low Med High XP
1 DC8, 1d6+3, HP 24 DC12, 1d8+4 (5), HP 30 DC19, +6/+8, HP 38 100 / 25
2 DC9, 1d6+4, HP 30 DC13, 1d8+5 (5), HP 38 DC20, +7/+9, HP 48 125 / 31
3 DC9, 1d6+5, HP 36 DC13, 1d8+6 (6), HP 46 DC21, +8/+10, HP 58 150 / 38

Average AC & to hit AC = Level+5
Average Defences & to hit Def = Level+3

That’s all of Fourth Edition D&D from a DM’s perspective from 1st to 3rd level, in a nutshell. Here’s the full thing from 1st to 30th level.

The columns marked Low, Medium and High show three different values each. The first is the Difficulty Class (DC) of any given skill or attribute check at that level. A High (ie, Hard) DC check at Level 3 is DC21, for example.

The next value is the damage. In general, use the Low column for attacks which affect multiple foes, the Medium for the majority of attacks and the High column for powerful or special attacks which can only be used a limited number of times per encounter. The value in brackets in the Medium column (where it says 1d6+4 (5) at 1st level, for example) gives the damage value for Minions. I also use that value for Ongoing Damage as well, to keep that scaling up the levels neatly.

The High column shows no dice notation as High damage always uses the same number and type of dice as Medium damage. There’s two numbers separated by a slash; the first is for a regular High damage attack, and the latter for a Limited High Damage attack.

I could (on the fly, right now) invent a Purple Dragonnette at Level 3. Its Bite Attack does 1d8+6 damage and Tail Swipe does 1d8+10 (High damage, Limited) and Slides opponents 1 square against opponents foolish enough to get behind it. The breath weapon is a cloud of noxious purple fumes that does 1d6+5 damage as a Close Blast 3.

The last part of the High/Medium/Low columns show the Hit Points, depending on whether you want this particular monster to be tougher (in 4e-speak, a Brute) or weaker (a Lurker, for example) than the level would represent. The Purple Dragonnette above might have High Hit Points  (58) as a 3rd Level critter while a cowardly Blue Orc (also 3rd Level) might have Low Hit Points (36) to reflect his eagerness to lay on the floor and play dead until the nasty heroes go away.

The final column shows the XP value of a Monster or Trap at that level, with the number after the slash giving the XP value for Minions. The note at the bottom of the table shows how to calculate AC, Defences and to-hit values. The Purple Dragonnette would have AC 18 and other Defences 16. The Bite Attack is AC at +8, Tail Attack vs Ref and Breath Attack vs Fort at +6.

Note that all of these are just average values – if you want a monster to be particularly agile for example, adjust Reflex Defence up by +2 and lower one of the others by –2 if you want to balance things out. They’re the products of your imagination, so use the numbers as a guide and adjust to taste.

Add other effects of damage to keep that 4e feel. Use Push, Pull and Slide to keep the game mobile, and use conditions for particularly nasty attacks. The Purple Dragonnette’s breath attack could leave the victim in a coughing spasm (grants Combat Advantage (save ends)), or whatever effect your whimsy takes (turns them into pretty butterflies (Unable to attack or move other than Shift 1 (save ends)).

The thing is that this can all be done in-play. Put a ruler underneath the line equal to the party level (raise or lower it if you want high or lower level foes for this encounter) and just pick the numbers for the creatures and traps as you go. I jot down minimal notes about the creatures for later reference such as “Purple Dragonnette 3, HP 58, AC 18/16, Bite M +8,Tail HL&Slide1 +6R, Purple Cloud CB 3 L +6F”. Not just easy – old school easy!

The same table can be used for Traps. A column of flame which shoots upward when a pressure plate is pressed could be a Level 2 Trap doing 1d8+5 damage + 5 Ongoing (save ends), +5 vs Reflex. Use the DCs for any skill checks (jumping across a Flaming Pit, or scaling a Gelatinous Wall) and the damage results for any consequences of failure.

If you’re letting the players roll all the dice just give them the appropriate DC for the attack (10+Level+5 for AC, or 10+Level+3 for any other Defence, modified by whimsy) and the damage value. You can focus on telling the story while they roll the bones.

What this does is take the game back into the unknown.

You are no longer using familiar foes from the Monster Manual, but creatures which the players (and therefore the heroes, by association) have never previously encountered. That short green ugly humanoid might well be a Goblin, but he won’t be like any Goblin they know. This one could be a Feyrie Goblin, a Level 1 creature that can become Invisible until the end of its next turn when it hits with its Unsee-Me Stick (Medium damage, +6vsAC). Or a Moss Goblin that infects its foes with Moss Rot with a touch (Level 1 Minion, +6vs Fort, 5 Ongoing Damage. On death, victim turns into a small mound of moss-covered topsoil). Or any one of a thousand other unknown creatures from your mind.

If you use just this one sheet and pass the dice over to the other side of the table, you’re free to focus on the story. There’s no jumping between rule books or flipping from one Monster Manual to the next. All of the numbers you really need are right there in front of you all the time. The part of your brain which usually focuses on finding the right page or worrying about the next encounter can instead come up with cool details, plot twists or throw itself into characterization. That’s a good thing, right?

And all that prep time –  gone. Spending four hours to prepare a two hour session is a thing of the past. Dream up a starting point for the scenario on the way over, and use the extra free time you’ve gained in-game to dream some more. Zero prep role-playing is the art at its finest, true collaborative story-telling with no rail-roading at all. Heck, there’s no rails to road.

If you’re the kind of GM who loves the comfort blanket of preparation, it takes a massive leap of faith to give it a try, but I heartily recommend it. It’s a step into the unknown.

Welcome to the ways of the unconstrained GM. You’re a part of the club now.

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15 Responses

  1. That’s a pretty good way of doing it. It fits into my style of DMing 4e. I’ve been doing a similar thing for the my Traveller campaign (even easier there as there are no levels and UPPs are easy to list) but I hadn’t really wrapped my head around doing the same for 4e. I guess the ways the rules and source material is written for 4e is designed to imply that you can’t do it like that.

    Thanks for your article.

  2. I like it very much. Was thinking about starting my sandbox making “generic” monsters to throw at the party before some threats are more detailed. But this way it’s even better. Thanks. Downloading and totally using. :)

  3. Oh! And old-school stats are way cool BTW :)

  4. Darktouch says:

    Oh very nice. I don’t currently play 4E but this looks like it would work extra well with some of the simpler essentials characters.

  5. Robert says:

    This is really great! I especially like the way you have compressed the stat blocks. Wizards needs to see this.

  6. Simple guidelines to run any 4E game on the fly! Awesome. RT @greywulf The Unconstrained GM #rpg

  7. Alphastream says:

    Very nice! However, I’m not sure I like the absence of damage values for the “High” column. Monsters typically have a hard-hitting power that provides a high damage spike. Or, they have riders that come with some of the powers. Kobold Slinger in MV is 1d6+5 for basic attack, but has 3/enctr to add an effect. Grasping Zombie does 1d12+3 or more on a grabbed target and can also attack to just grab. The Horse (I’m using level 1 MV examples) has a basic of 2d6+4 and then can trample as an encounter for more against several targets.

    If the monster is simple and has basically just an at-will attack, that damage is usually higher (take a look at the MV dire rat, just attacks for 1d10+5 and disease).

    For damage alone, it might be worth listing the average damage value from Chris Perkins’ recent article. That can serve as a guideline… if you have 1d6+3 basics, you need something else to reach the average at-will of 9 and the enctr average of 13 for a level 1 monster.

    It is also important to state that the sheet you provide needs a few caveats for non-experienced DMs. Cool monsters don’t just have HPs and attacks. They are descriptive agents of narrative. Encounters gain life when the monsters do awesome things that are in tune with the narrative. If your encounter is all about a city block that is on fire, the monsters should have powers like Aura of Flame, Scythe of Smoke and Fire, Flameburst, etc. When running things on the fly it is important not to leave this out. Experienced DMs know to do this, but less experienced DMs might take the above sheet and just roll some lame damage in a lame situation. 8×8 room with 5 monsters dealing non-descriptive average damage does not make for fun play. In contrast a good DM can take average damage and use it as a tool to on-the fly create awesome combats without extensive prep. A monster might have average damage plus vulnerable fire, with a follow up minor attack that provides ongoing fire. That sort of quick-thinking is hard to master (a lifelong project for most of us).

  8. Eodrid says:

    I’ve used Sly Flourish’s cheat sheet on the fly for monsters and skill DCs in the past, it works great. I wrote up a two page monster manual in a notebook with 1-2 line entries like:

    Flying Eye Scout–Artillery 1, Burning Eye (ranged 10, vs Fort, fire damage), resist 5 fire
    Flying Eye Sporeplanter–Controller 2, Lashing Tendrils (+immobilized), Implant Spores (targets immobilized, vs Fort, high damage+ongoing 5), if target brought to 0hp by Implant Spores place Flying Eye Scout minion in square next turn

    When you don’t have to waste time doing the math, you have time to come up with more evocative powers. Plus, if I read a cool power on a monster, I can just steal the framework, rework the numbers and done. You can reskin anything lightning quick.

  9. This is a great breakdown and something I will definitely use in my next game. I am always looking for ways to “enhance” a game on the fly and this seems to fit the bill. Great piece, thank you very much.

  10. Jonathan says:

    This is just brilliant – I really must bookmark this page. Thanks, Greywulf!

  11. Genesys RPG says:

    Excellent post and blog site. I saw you on twitter under the “who to follow” tab. I am developing a universal RPG that is rules lite and fast to play, you can check out our webstie at: I have a few more slots open for playtesters, and currently have a few play testers in the UK (I am based in the US). If you are interested in playtesting, email


    The Genesys Team

  12. Thorynn says:

    This is genius. You’ve got it boiled down to an index card’s worth of info. Well done!

  13. kyhan says:

    Wish there was something like this for 3.5. 4e is too boring and every character ends up doing the same thing under different names. 5e looks promising so far.

  1. December 7, 2011

    […] One Page Bestiary is being reworked, as I reread Greywulf’s The Unconstrained GM and now have a better idea. Meanwhile, here it is, preserved for […]

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