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Let There Be Law


World building is my favorite part of gamemastering, but (despite the countless hours I devote to it), world building cannot be counted as the primary or even secondary role of the gamemaster. A GM can be an amazing judge, storyteller, and adversary without ever taking up the art of world-building. In fact, the majority of gamemasters never create their own worlds or settings, instead relying on pre-established settings such as Forgotten Realms or Warhammer Universe. Pre-established settings became popular within the first generation of the tabletop gaming hobby, and they have only increased in popularity since then. Nevertheless, I believe that even if you don’t intend to create your own world, an understanding of the art of world building can only deepen your skills as a gamemaster; much the same way taking film classes can help you appreciate film even if you don’t ever direct one. Whether you are crafting your own sandbox or running D&D Encounters in 4e, there’s much to gain by studying the art of world building.

Start with Rules and Genre

There’s a certain school of thought that says that the setting of a game, the genre of a game, and the rules of a game can all be divorced from each other. This school argues that one set of rules is just about as good as another, and all that counts are how the GM weaves it together. In fact, this premise underlies the rise of the D20 Open Gaming License in the 1990s. I’m not part of that school! I believe they have to form an organic whole.

On this point, at least, I did some interesting research. As my thesis project at Harvard Law School, I conducted a study on how the design of 3 different massively multiplayer games affected the societies of those games. To cut short a 100-page research paper, the answer was “strongly”. It turns out that every set of game mechanics carries with it certain implicit and explicit assumptions about how the world works. They are the physical laws of the game world. Just like the law in the real world affects our societies, the laws in the fantasy world do, too.

While the research was for MMOGs, tabletop examples abound. For instance, Cyberpunk 2020’s Interlock System offers a 10% chance for any given roll to be a critical success and a 10% chance for a critical failure. Cyberpunk 2020 therefore implies a world where any punk can get lucky, and even the best of the best are eventually going to bite it from bad luck. If that’s not how your world works, you don’t want to use Cyberpunk 2020 to run it. Because what will happen is that punks will get lucky, and elites will die young.

Another example: Classic Traveller uses a fascinating character generation system in which players choose or are drafted into “careers” for their characters, such as army, marines, or merchants, and then spend anywhere from 4 to 20 years in service, graduating into play as seasoned experts. There’s little to no character improvement thereafter. Classic Traveller therefore implies a world the opposite of the traditional “Heroic Myth” – age and experience trump youth. Young characters aren’t potential heroes ready to unlock their potential; they are unskilled mooks. Luke Skywalker doesn’t become a Jedi master, he dies. Classic Traveller also implies a world with lots of organized, institutional careers, diametrically opposed to the post-apocalyptic environment of most D&D campaigns. This is why so many efforts to use Traveller as D&D in space fail.


So before I begin building a world, I always decide what rules set I’ll be using and what genre I’ll be simulating. The choice of rules needs to be made simultaneously with the choice of genre. Some rules really can support multiple (if not all) settings and genres – Steve Jackson’s GURPS and Chaosium’s Basic Roleplaying come to mind. Other rules sets support particular genres marvelously, but fail spectacularly outside of them. Palladium Games’ classic RECON is a brilliant war movie RPGs, but is dreadful for heroic fantasy. D&D is great for heroic fantasy but lousy for investigative horror. Some rules sets are so narrowly tailored as to support not only just one genre, but just one setting; due to the career and magic system, it’s hard to extract Warhammer Fantasy from the Old World setting, for instance.

It’s possible to “hack” a rules set to support different genre conventions and settings, of course. And if you are trying to use a particular rules set (say, D&D) with a genre or setting it’s not built for (say, the American Old West), you will need to. But with so many game systems available, and so many other challenges to gamemastering, it’s probably better to find a game system that lines up with the genre and setting you want, unless you just love tinkering with rules.

I personally find universal games like GURPS or BRP to be so broad as to make the setting feel bland. On the other hand, I find games like Exalted, Warhammer Fantasy, and Castle Falkenstein exceptionally flavorful, but hard to modify or extricate from their assumed setting. My personal sweet spot is a lightweight rules set that is easy to modify, nicely tailored to a specific genre but not tied to any specific setting.

Here are the rules systems I choose when world-building in various genres:

Cyberpunk Cyberpunk 2020 (R. Talsorian Games)
Hard Science Fiction Traveller (GDW/Mongoose)
Heroic Fantasy Classic Dungeons & Dragons (TSR/Wizards of the Coast)
Horror Call of Cthulhu (Chaosium)
Post Apocalyptic Mutant Future (Goblinoid Games)
Space Opera Hard Nova II (Precise Intermedia)
Superheroes Mutants & Masterminds (Green Ronin)
Wild West Aces & Eights (Kenzer & Co)

If you are familiar with these games, you can probably identify why their mechanics support the genre. As already noted Cyberpunk 2020 has a “live fast, die young” game mechanics loaded with crits and botches. It also has an almost fractal depth of technology and gear combined with a clever “humanity loss” mechanic, where cyberwear slowly eats away your character’s empathy as he becomes more machine than man.

Traveller gets the hard sci-fi nod for its career path system, which creates characters who feel like they are part of a high-tech society, not isolated wanderers in the post-apocalypse. The original game even suggests that the “game statistics” are actually part of a universal hexadecimal rating system actually employed in the galactic society the characters live in. My rating is UPP 677BA8.

Dungeons & Dragons is an obvious choice because of its widespread popularity, but the popularity is not coincidental. By accident or not, D&D’s class and level mechanic perfectly encapsulates the enduring myth of the hero’s journey, wherein a youth is called to adventure and rises to greatness thereby. The reason D&D campaigns tell the same story over and over is because it’s the best story.

Reasons of space preclude further annotation but each system above has similar implicit or explicit mechanics that support the genre. Consider these my recommendations as to systems, or if less charitably disposed, a disclosure of my biases. Either way, let me know what you think in the forums.

Next time, we’ll look at top-down versus bottom-up design, and how to balance between consistency and openness.


Alexander Macris has been playing tabletop games since 1981. In addition to co-authoring the tabletop games Modern Spearhead and Blaze Across the Sands, his work has appeared in Interface, the Cyberpunk 2020 fanzine, and in RPGA AD&D 2nd Edition tournament modules. In addition to running two weekly campaigns, he is publisher of The Escapist and president and CEO of Themis Media. He sleeps on Sundays.

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