Decyphered: Simplified house rules for Numenera & The Strange

Featured image artwork is by Bear Weiter and is TM and © 2019 Monte Cook Games, LLC.

Monte Cook Games updated their fan use license to specifically prohibit use of their materials in Google Docs, so I’m reproducing my streamlined take on the Cypher System as a blog post. See the summary at the original post, Decyphering Numenera & The Strange.

Conversion Notes

This page presents some not-at-all-playtested rules for running Cypher System games (like Numenera and The Strange) with material from existing adventures and supplements. My hope is that it works like The Black Hack does for Dungeons & Dragons—it uses some of the same terms in slightly different ways, so you can use old modules, but it changes or eliminates some rules entirely, so it should feel more streamlined in play.

Unchanged concepts and rules from Numenera include:

  • Descriptor, type, and focus are chosen to define characters
  • Roll 1d20 on or over a target number to succeed
  • Effort improve rolls or damage, and points activate abilities
  • Running out of points steps you down a damage track
  • Edge can reduce point costs once per roll
  • Weapons & armor come in 3 sizes with fixed stats
  • Initiative is a Speed action vs. enemies

New and changed rules will be the focus of this document, including:

  • Roll vs. level+10 on d20 to test for success (instead of level×3)
  • Add to rolls (rather than reducing steps) when applying a bonus
  • Steps (“adjust difficulty by 1 step”) now refer to ±1 to rolls
  • Skills grant +1 for training, +2 for expertise (rather than ±steps)
  • Assets replaced with “advantage” (take best of 2d20)
  • Cover and other situational penalties impose “disadvantage”
  • Effort is +1 to a roll per point bid, no max, and kept if roll fails
  • Edges can be directly added to a roll if not used for an ability
  • Armor Might adjustment and Speed cost rules are ignored
  • Light weapon attack bonus rules are ignored
  • Hits always do something even if damage is reduced to 0
  • Damage track effects are simplified
  • Maneuver rules are greatly simplified
  • 17-19 special dice results are ignored here, but can still be used
  • Intrusions are suggestions for “suboptimal” roleplaying
  • Advancement costs adjusted to account for no max effort
  • Optional rules include “partial successes” and damage rolls

The Basics of Facing Challenges

When you face a challenge, the GM sets a target number from 1-10 to roll against (or uses an enemy’s level). If you can’t fail because your bonus +1 is at least as high as the target number, you don’t roll—you just succeed. Only players roll—in combat, players roll to attack on their own turn, and defend on enemies’ turns, with the target number as the enemy level, unless the GM states otherwise. So, in summary…

  1. Player says what they want to do
  2. GM says what the roll requires:
    • Which edge & pool to use—Might, Speed, or Intellect
    • Target number from 11-20, or enemy level + 10
  3. Player rolls 1d20, possibly applying any of the following:
    • Skill (+1 if trained, +2 if expert)
    • Special ability (which may have a cost in points)
    • Edge (either add to roll or subtract from an ability cost)
    • Effort (bid for +1 per point to d20 roll or damage)
    • Advantage or disadvantage (take best/worst of 2d20)
  4. Result succeeds if roll + modifierstarget number
    • Natural 1 is a failure plus added complication
    • Natural 20 is a success plus added benefit
    • Reroll by spending 1 XP, optionally, once per roll

Character Creation

Choose a descriptor, type, and focus from the core rules. When you choose special abilities (fighting moves, esoteries, and tricks of the trade), unless the GM specifically says they want to use the fiddly armor rules, just ignore any abilities related to the cost of wearing armor.

Special Abilities

When you want to use a special ability—a fighting move, esotery, or trick of the trade—it has a point cost as listed in the Numenera core rules. If you have an edge that would reduce that point cost, subtract the edge from the cost (which might even make the ability free). If your edge is higher than cost, you don’t get to use the excess edge for anything else.


Your character has an edge for each pool—Might, Speed, and Intellect. You can use an edge once per roll to either add it to your roll result, or subtract it from the cost of a special ability (as low as zero).


You can bid points from your Might, Intellect, or Speed pool to either increase the chances of succeeding on a roll (before rolling), or to increase damage on a hit (after rolling). This is called effort. Each point bid adds +1 to your roll or your damage. (Area attacks cost extra—2 points per +1 to roll or damage for the whole group, unless the GM is okay with you specifying individual targets who are easier to hit or take extra damage.) Points bid on a roll that fails are kept; you only spend the points if the roll succeeds. You can bid as much effort from a single pool as you want at a time, but when a pool runs out, you drop down the damage track (see ”Suffering Harm,” below).

Assets & Aid

If you make use of something that might provide an asset for a roll (e.g., vines hanging down over a wall you want to climb), you have an advantage, and can roll an extra d20 and use the better result. Alternatively, if you are at a disadvantage (e.g., enemies firing down at you from higher ground), you roll an extra d20 and use the worse result. You only ever roll one extra die, and a source of advantage cancels a source of disadvantage.

If, however, the GM wants greater granularity in any given scene that has multiple sources of advantage or disadvantage (e.g., avoiding ranged weapon fire with some cover and moving in the dark), the GM might also or instead tell the player to adjust their roll by 1 or 2 in one direction or the other.

When one character assists another, this typically grants an advantage if they can describe how they help. Being trained or an expert in the task may be a prerequisite to assisting, or may grant an additional bonus.


If you want to do something during combat more involved than dealing damage, but you don’t have an ability to cover it, you can attempt a maneuver. If the maneuver is instead of a damaging attack (e.g., tripping someone to knock them down), just handle it like a normal attack roll, but apply the maneuver’s effect instead of damage. If the maneuver is in addition to a damaging attack (e.g., hitting someone so hard it knocks them down), roll 2d20—one to attempt your maneuver, and one to avoid suffering some kind of complication for overextending yourself. You can decide which die is which after you roll.

Skill Training & Expertise

If you’re trained at something, you get +1 to your roll. If you’re an expert, you get +2. As in the core rules, you don’t get any better than expert.

Using Cyphers

Cyphers are single-use items with strange abilities. Player characters can automatically identify cyphers and what they do. (The actual purpose might have once been “transdimensional drive core,” but an explorer, it’s “a familiar design—an explosive device that teleports anyone caught in the blast, as best as I can tell.”) Occultic cyphers are more complex to use than anoetic cyphers, but consider this narratively relevant rather than mechanically relevant.

If a character is carrying more than their cypher capacity, anytime they fail a roll, a random cypher is accidentally destroyed or activated, affecting a random or narratively sensible target at the GM’s discretion.

Weapons & Armor

Weights for weapons and armor are just as in the core rules—light (2 damage/1 armor), medium (4 damage/2 armor), and heavy (6 damage/3 armor)—with usage restricted by character type. When dealing damage, subtract the target’s resistance value from damage dealt.

If armor drops damage to zero, the target still suffers some other effect other than being damaged. A hit is a hit, so an attack that deals no damage might still disarm, knock down, reduce armor value by 1, or reveal a weakness that might be exploited on the next roll. Players can suggest effects, with the decision up to the GM.

Suffering Harm

When you take damage, you lose points from an appropriate pool. When you run out of points in a pool, you drop a step down the damage track, and any additional damage is deducted from another pool of the GM’s choice. When you have no more points to lose, you are dead. The damage track here has the same nodes as on the character sheet, but with simplified effects:

Hale: You’re doing great. No pools at 0.

Impaired: One pool at 0. The GM describes a temporary condition, like being winded or having a sore ankle. If you try to do something that the condition would interfere with, you’re at a disadvantage—take the lower of 2d20 on affected rolls.

Debilitated: Two pools at 0. The GM describes a more serious or lasting injury, depending on the source. You probably can’t do much more than crawl. You might have lost a body part.

Dead. All pools at 0. Time to make a new character.

Refilling Pools

When you have a chance to catch your breath and rest, you regain 1d6 + your tier in points, distributed between your pools however you like. Resting takes progressively more time each time you attempt it (seconds, then minutes, then hours, then a day). The time resets back to the lowest unit after you rest for an entire day.

Earning Experience

Characters gain experience in two ways: intrusions and exploration.

Intrusions operate as in the core rules, but narrower in scope and at no cost to unwilling players: The GM offers 1 XP to suggest a complication that might arise specifically from a character’s descriptor or focus, like a tough character overestimating their own toughness, or someone who bears a halo of fire accidentally igniting something. If the affected player agrees, they roleplay the complication and gain 1 XP. They can award 1 XP to one other player affected by the complication.

Exploration experience is awarded after a session. For each “yes” answer to the questions below, everyone in the group earns XP:

  • Did we retrieve a forgotten treasure of lasting value? (+1 XP)
  • Did we explore an unmapped location? (+1 XP)
  • Did we overcome a notable threat or enemy? (+1 XP)
  • Did we discover a way to improve people’s lives, and share it with anyone else who might benefit? (+3 XP)

Spending Experience

Experience can be spent for either of two uses: rerolls and upgrades.

Rerolls allows players to make instantaneous course-correction or double-take, making an extra attempt at success immediately after failure. This can only be attempted once per failed roll.

Upgrades each cost 5 XP. Buying any 3 upgrades raises a character 1 tier. Upgrade options include:

  • +4 points distributed as you like between pools
  • +1 to any one edge
  • Training, or upgrading training to expertise, in a non-combat skill
  • A new type ability (fighting move, esotery, or trick of the trade)

Time & Turns

When things aren’t hectic, players just describe what they do conversationally, and the GM tries to help make sure everybody gets some time in the spotlight. During action sequences, like combat, everyone takes turns. To determine the order that characters act, players roll for initiative (a Speed action); anyone who succeeds goes before enemies, and anyone who fails goes after. Players can decide among themselves the order to act in when it’s not the enemy’s turn.

Anything Else

For any other rules not addressed here (like range, movement, etc.), refer to The Black Hack or your own favorite simplified system.

Step-by-step Summary of a Roll

  1. Intent: Player says “I want to ______”
  2. Difficulty: GM notes…
    • “This relates to _____” (Might, Speed, or Intellect)
    • “Roll _____ or higher” (11–20, or enemy level +10)
  3. Roll: Player rolls a d20, possibly with…
    • Skill (+1 if trained, +2 if expert)
    • Special ability (may cost points)
    • Edge (subtract from ability cost, or add to roll)
    • Effort (+1 per point bid to roll or to damage)
    • Advantage (roll extra d20, take best result)
    • Maneuver (no damage, or roll a d20 vs. complication)
    • Reroll (may spend 1 XP to reroll failure, once per roll)
  4. Results: Player describes what they do, and GM adds details and/or describes how NPCs and the environment are affected:
    • Under target number fails, and points bid are kept
    • On or over target succeeds, and points bid are spent
    • Natural 20 gives +4 damage or other major benefit
    • Natural 1 applies an additional complication

Additional Optional Rules

Trinary rolls allow for a partial successes in additional success and failure. In this variant, the GM instead sets a lower target number from 1-10 (or equal to an enemy’s level), and an upper target +10 over the lower target:

  • Succeed on a roll above the upper target
  • Succeed at a cost on a roll on or under the upper target, but over the lower target
  • Fail and suffer a cost on a roll on or under the lower target

Costs might include lost resources, collateral damage, being put in a spot, or another complication. When using this rolling system in combat, each roll is assumed to be a clash between the attacker and the defender, where either or both could do damage or execute a maneuver.

Roll for damage instead of using static damage numbers. Light weapons deal d4 damage; medium weapons, d8; heavy weapons, d12.

This is a fan work only and not officially endorsed by Monte Cook Games. Featured image art is TM and © 2019 Monte Cook Games, LLC, used under the Monte Cook Games Fan Use Policy.

6 thoughts on “Decyphered: Simplified house rules for Numenera & The Strange

    1. Yeah, I never actually ran it. I think the driving conceit was flawed from the outset. Rather than “I want to make a fun game,” I was trying to solve the problem of “I paid for all these Cypher materials I’ll never use unless I come up with a way to make the rules more like something I want.” I think my big takeaway in the nearly two years since I wrote this is “just use a system you DO like, and let yourself be inspired by the material you’ll never use as-written.”

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