Writing RPGs is Hard, Part 3: Dice Pools

Reading the “quickstarts” for Mutant: Year Zero and Forbidden Lands¹ has sparked some thoughts about the Untitled dice pool system I’m temporarily calling “The Third System”.

The Year Zero System

Mutant: Year Zero, from Free League Publishing², uses a d6 dice pool mechanic:

1. Assemble a pool of color-coded six-sided dice:

   • Base Dice equal to the base attribute being used.
   • Skill Dice equal to the skill rank, possibly modified by difficulty
   • Gear Dice for the quality of equipment being used.

2. Roll all dice; the character scores one Success for every 6 rolled.³ Usually one will suffice, but sometimes extra successes activate extra effects.

3. After the initial roll a player can “push” their roll: they reroll any Skill Dice not showing a 6 and any Base Dice or Skill Dice not showing a 6 or a 1. Any 1 from the initial roll or the new roll has the following effect:

   • Each 1 on a Base Die⁴ diminishes the Base Characteristic used in the roll; when a Characteristic hits 0, the character is Broken: beaten, exhausted, confused, or demoralized, and barely functioning. Each 1 also gives the character a Mutation Point (MP). Characters expend MP to activate their mutations.

   • A 1 on an Gear Die⁵ decreases the Gear Bonus for the gear in question by 1. A “Gearhead” (PC or NPC) can attempt to fix it but if they fail the bonus is stuck permanently where it is; at 0 trying to fix the gear will break it permanently.

   • Skill dice have no ill effects on a 1.⁶

4. If a player rolls no successes, whether they push or not, the character doesn’t simply fail a task; they lose something. Mutant Year Zero recommends only rolling dice when something is at stake; by definition, a lack of successes means a definitive loss.

Subsequent games from Free League use the same basic mechanics with slight tweaks:

• Forbidden Lands calls their 1 results “banes”⁷, which translate into physical fatigue or equipment degradation. Forbidden Lands also calls Gear Dice “Weapon” or “Equipment” dice, based on context, and uses at most two d6s for normal gear. Artifacts use a d8, d10, or d12 Equipment Die based on power and rarity; the die supplies two successes on a roll of 8 or 9, three on a 10 or 11, and four on a 12.

• Coriolis doesn’t use distinct Base, Skill, and Equipment dice, and 1s have no special adverse effect. Players can still Push a roll by “praying to the Icons” (gods), but every time they do the GM gets a Darkness Point to mess with the players later.

• Tales from the Loop and Things from the Flood, like Coriolis, appears not to distinguish the source of dice or special failures on a 1.

• An upcoming Alien RPG appears to use “Base Dice” simiar to Coriolis plus yellow “Stress Dice” with a facehugger symbol for the 1.⁸

The “Third System”

What I was calling “Untitled RPG #1” and am calling “The Third System” counts 5 or 6 as successes. As originally stated it has no consequences for rolling other numbers. Also as stated before, each level of Difficulty subtracts one die from the player’s dice pool, because Players Roll All Dice in this system.

If the player ends up with zero dice, they could still attempt a Luck Roll: roll two dice, and both must show 5 or 6 to count as one Success. For each point below zero the total dice pool drops add one to the Luck Dice pool; again, all dice must show 5 or 6 to count as one Success.

In retrospect, subtracting dice and Luck Rolls are a bit difficult to explain. One morning at a coffee shop, I came up with a few other options to represent difficulty:

• Danger Dice: Add a die of a distinct color (black?) for each point of “danger” or risk the character wishes to assume. Each 6 rolled on a Danger Die is a Success, but each 1 rolled is an Anti-Success (Bane?) that negates one Success. If Anti-Successes remain after all Successes have been negated, the PC suffers a Complication.

• Doom Dice: An even stronger version of Danger Dice, for when player characters are really playing with eldritch fire; replace one or more dice in the player’s pool with (red?) Doom Dice. 5 or 6 count as a Sucess as normal, but any 1 indicates an anticipated Doom has fallen. (Inspired by the Hunger mechanic of Vampire: The Masquerade 5th edition.)

• Fortune Dice: To represent favorable circumstances and calculated risks, add one or more dice of yet another color (blue?). Every 6 rolled generates 1 Success. If taking away dice from the player’s pool, take Fortune Dice first.

• Misfortune Dice: To represent unfavorable circumstances and unavoidable risks, add one or more dice of yet another color (yellow?). Every 1 rolled generates 1 Anti-Success. If Anti-Successes remain after all Successes have been negated, the PC suffers a Complication. A roll cannot contain both Fortune and Misfortune dice; remove one Fortune and one Misfortune die before rolling until only Fortune or Misfortune remains.

• Rival Dice: The player rolls Yet Another Color (purple?) equal to the Ability of an important NPC actively opposing a PC. Every 1 or 2 generates an Anti-Success that takes away one of the PC’s Successes. If the dice show as many Anti-Successes as Successes, either nothing changes or each side suffers some small loss; if Anti-Successes dominate, the NPC definitively wins and the PC loses.

If only for my own sanity, here’s a summary of the above:

This is way too many dice types and colors. I’d like to limit it to three, maybe Ability, Fortune, and Danger.

• Doom Dice, if they exist at all, would only result from plumbing things Man Was Not Meant To Know.

• “Misfortune” is a less interesting version of Danger; extra risk can open up extra opportunities.

• “Rival Dice” wouldn’t exist if we were less dogmatic about Player Rolls All Dice. Instead, the GM could roll dice in Opposed Rolls on behalf of NPCs, at the same time as the player rolls to keep things moving. The GM would only employ this mechanic in rare circumstances, e.g. climactic battles with the main antagonist, or rare and unfortunate cases of player-vs-player conflict. Introducing Opposed Rolls would change the dice mechanic slightly.

  • Fortune dice on each side cancel out before rolling.

  • The (active) player rolls any Danger Dice; on a 6 the player’s character gains a Success while on a 1 the opposing character gains a Success.

  • If one side would be reduced to a Luck Roll, that side simply has zero dice and no successes for that round. (Difficulty modifiers probably wouldn’t apply; the GM would instead assess Fortune to one side or another.)

Compare and Contrast

The “Year Zero” system does sound simpler in comparison, if only because every die type works the same way and color only matters on a failure. Unfortunately, when only a 6 is a success players need to throw about twice as many dice. Below are numbers from the “Forbidden Lands Quickstart” and the corresponding percentages for successes on 5 or 6.

In my system I was trying to avoid rolling more than 5 dice and rerolls for players to have a decent chance of success. In the Year Zero System a character has no characteristic lower than 2, and “average” is 3; skills and equipment merely add dice. In Traveller, by comparison, a player rolls 2d6 and suceeds on a total of 8 or more; without modifiers from attributes or skills they have a 42% chance of success. (This could happen if the character has “average” attributes and a skill level of 0, meaning trained in the basics but little else.)

Also note that in both the Year Zero System and my “Third System” players can “spend” successes for additional effects. From some brief simulations in AnyDice it appears a Year Zero System roll (without pushing) generates nearly the same distribution of Successes as “Third System” with twice the dice.

Mechanical differences also reflect different settings. In Mutant: Year Zero sterile mutants struggle for survival in a dying world. In Forbidden Lands adventurers cross into a cursed land seeking loot. Tales from the Loop and Things from the Flood take place in our recent past but filled with strange machines and unknown creatures. In Coriolis and presumably the Alien RPG characters brave the vacuum of space and alien worlds. In all these cases PCs’ biggest threat is the world around them. Without sufficient ability, training, and gear, chances of success are low.

The notional setting for “Third System” is a science fantasy post-apocalypse inspired by Miyazaki’s Nausicaa and other works, The Vision of Escaflowne, Thundarr the Barbarian, and especially the Netflix She-Ra series:

The Age of the Ancients ended abruptly and mysteriously. They left behind only forbidding monuments, incomprehensible artifacts, bio-engineered flora and fauna, terrible techno-organic monsters, and dangerous powers that sorcerers attempt to master.⁹ Many areas remain uninhabited or at least unexplored.

Over untold generations mankind rebuilt.

We rediscovered the secrets of farming, of shaping wood and metal, of harnessing wind and water. While this New World may not be as peaceful or as plentiful as the Ancient World of legends, we settle most of our differences without bloodshed.

In recent times despots from another world arrived to plunder this one. They build terrible engines of conquest and threaten our hard-won peace. They are yet few, but their numbers are growing and their weapons are terrifying. Our nations are divided; our leaders argue and do nothing. Who will defend us?

While post-apocalyptic, the premise is fundamentally optimistic. Ideally, player characters defend their homes and their world from rampaging monsters, conquering hordes, and power-mad sorcerers. They have special knowledge and training that gives them a huge advantage over conscript soldiers and mundane perils. Even outside their comfort zones they have a decent chance – 1 out of 3 – of muddling through most situations. Their opponents are beings as well or better trained than they are, threats from the Time of the Ancients, and new menaces from beyond the world they know. Thus players don’t need to roll dice so characters can climb a tree unless they’re under significant time pressure … and somebody or something is making them hurry. A guiding rule of the Third System is that characters – PCs and NPCs – always succeed unless another character opposes them¹⁰.

After seeing Forbidden Lands I kinda want to add a “Power Die”: a d12 (or in a pinch two sparkly pink d6s) representing the astounding effects of Ancient Artifacts¹¹: 50% no Successes, 17% one Success, 17% two Successes, 8% three, 8% four. Intact Ancient artifacts might take time and effort to unlock, but once someone does it literally blows away common gear¹², wonders of sorcery¹³, and the Empire’s “Nu-Tech”¹⁴.

It’s a cute idea, but early on I decided that intact Ancient Artifacts always work as designed and do what they’re told, even if that isn’t necessarily what the user wanted. Random and variable effects almost sounds like a Sorcery thing.

So for now, to the extent I’m working on this at all, I’ll stick with my original mechanics: Ability Checks where 5 and 6 are Successes, Difficulty modifiers to reduce the dice in Ability Checks, and Luck Rolls for cases where players still have a slim chance. Fortune Dice, Danger Dice, and Opposed Rolls will remain in my back pocket unless I need them. I’ll only use Doom Dice for Sorcery or similar Faustian bargains, and only if there’s a compelling case.

Postscript: While developing the setting (and rewatching She-Ra), I’m thinking about adding yet another faction, the Dominion of Light. They’re a faded but still dangerous empire in which immortal, magical beings rule “benevolently” over human slaves. Just to deconstruct even further the anti-technology and pro-aristocracy biases of most fantasy.

Post-Postscript: Also, I want PCs to be heroes of the people (emphasis: of the people), not stereotypical murderhoboes, the setting’s newest warlords, or the ultimate conquerors.¹⁵ How to discourage the Evil Option when a) player characters are effectively superheroes and b) players and GMs can do whatever they want with my work, I don’t know. Hopefully I’ll think of something less clumsy than Exalted’s “everyone instinctively hates Exalts”. Two evil empires and a lot of angry villagers might do the trick … or it might not.