Self-Balancing RPG

Hello Readers of the Martian Muckraker blog and/or!

This is a super early draft of a rules framework that GMs and players can used to build characters for any environment. Occurrence values, all based around the number twelve, are used to determine the relative utility of skills, powers and environments in a given setting. The GM defines the skills and the environments, and sets how many Skill Points and Power Points the players have. The players then buy skills and invent their own powers. The number of environments the power can be used and the relative importance of the goals the power are used for drive up the cost. Limitations on using the power decrease its cost.

Different characters will feel mechanically different – as some will be focusing on certain goals in certain environments, others will emphasize other goals and have different limitations.

Ark 12 Self-Balancing RPG

  • Characters in an Ark12 Adventure want to find Evidence Points.
  • Evidence Points are the goal of all actions of an Ark12 Adventurers
  • Therefore, powers, actions and anything else are useful to the extant they conduce towards the finding of evidence points.
  • Occurrence is a value set by the GM when setting up an Ark12 game. It determines how important something is forecasted to be for the finding of evidence points.


Occurrence is always measured from 0-12. Zero means that its not relevant to your campaign. 12 means it is always relevant to finding evidence points.

Note bold terms are key terms in the system, italics terms are terms definded by a GM for a specific example use of the system

Goals and Actions

All actions are going towards one of six goals. The six different goals are listed below including a sample occurance score. Occurance values will be changed by the GM depending on how much emphasis they want to place on each goal. These goals are genre-agnostic.

  • Investigation – search an object for clues that give evidence points (Occurrence 3, investigation can never be lower than 3 unless all evidence points are coming from building connections)
  • Solve Problem – A problem for so long as it exists prevents certain actions from being taken, or imposes a cost upon those actions being taken. (Occurrence 2 – in this example the GM sees Investigation as always being needed to find evidence, but most evidence being behind some set of problems. Because problem solving is usually needed but not necessarily always an occurrence of 2 is set)
  • Scouting – Identify (potential) problems in an environment (Occurrence 1 – strictly speaking evidence can be found without scouting. May be risky. But in theory it can be done.)
  • Connect – Build relationships to a sentient creature (Negative connections are connections!) A connection is a descriptor that changes how that creature behaves towards the PC that produced the connection. (Occurrence 3 GM wants equal weight on social connections and investigating the environment). Some connections functionally release evidence points from the NPC sharing what they know or the NPC doing a favor that grants opportunities, like a Guard agreeing to the let the party into the city gates.
  • Combat – defeat an enemy, usually to clear an environment so investigation can take place (Occurrence 2 the GM knows combat will occur, but Investigation and building connections will be more important)
    • Attack – try to place damage on a creature
    • Defend – try to avoid damage from an attack
  • Produce Factor – A factor creates a specific bonus or debuff to a future action (usually -2). (Occurrence 1, as scouting producing advantages is less essential than Investigating, Solving Problems or building Connections)

You will notice that the sample occurrence values set by a hypothetical GM add up to twelve.

For any given setting there will be a set of skills consisting of a name , situation guidance and goals those skills can be used for. Skills used for the game goals should be equally valuable, just applied to different strategies or situations or associated with different narrative effects. Skills will also have a skill value that will be important in character creation. This skill value is the sum of associated goal’s occurances.

So in a fantasy setting, continuing the work of the GM above:

  • [Skill] – [Situation guidance] – [Goals] – [Skill Value (sum of goal occurances)]
  • Thief’s Craft – Crime scenes analysis, used when interacting w – Investigation, Solve a Problem, Scouting – 6
  • Naturalism – Environmental interaction – Investigation, Scouting, Solve a Problem – 6
  • Engineering – Work with devices – Solve A Problem, Produce Factor – 3
  • Melee – Physical attacks – Attack (Combat) – 2
  • Block – Protect from physical attacks – Defend (Combat)- 2
  • Ranged – Ranged attacks – Attack (Combat) – 2
  • Dodge – Protect from Ranged attacks – Defend (Combat) – 2
  • Intimidate – when using threats to install negative connections – Connect – 3
  • Compassion – when trying to build deeper relationship wit a character, or help that character solve a problem – Connect, Solve A Problem – 5
  • Diplomacy – when trying to convince a character with whom you have no connections, or to build a business connection – Solve a Problem, Connect – 5

Skills are tested on a d20 by attempting to roll equal to or underneath the score. On a success the character achieves their goal or at least accomplishes the part of it the skill was addressing.

Health and Other Character Resources

Often a GM will want to define personal resources that a character needs to maintain, like health (which is universal to most ark 12 games), sanity and energy. These can be lost through damage from attacks, or as a consequence of certain narratively appropriate roles, or by using certain powers (more on that below)

The starting value of a resource can be set in different ways. One way is to define different ancestries/species/races/themes/types (as fits setting) that determine the starting values. In this case, all characters get +2 to health before the “type” bonuses. All types should have the same number of points in resources (the +2 accounts for health being more important than the rest, and thus needs to be higher).

So for example

  • Elf Health: 8 (+2) Energy 8 Sanity 10
  • Orc: Health 10 (+2) Energy 10 Sanity 6
  • Human Health 9 (+2) Energy 9 Sanity 8 would be a legitimate set of types, called “Ancestries” to fit the setting to pick from. Each has Energy, Sanity and Health bonuses that add up to 26 in this case.

Another way is for each Resource allow the player to set it equal to one of two skills. So the GM reasons that Melee and Dodge both reflect physical wellness. As such a player can set their starting HP to either their Melee or Dodge score.


Like goal occurrence, Environmental occurance is likewise rated 1-12.

So for example a fantasy campaign may define –

  • [Environment] – Occurrence – Description
  • Dungeon – 4 – any enclosed / underground environment
  • Forest – 2 – wild environment with much plant growth
  • Urban – 2 – Outdoor City
  • Dessert – 2 – Wild area with limited growth
  • War Torn – 2 – Area destroyed by effects of war

There can also be derived occurrences

  • Any Outdoor – 8 (Forrest, Urban, Dessert, WarTorn)
  • Any – 12 (All environments)
  • Any Wild – 4 – (Forest, Dessert)
  • Any Civilized, for better or worse – 8 (Dungeon, Urban, WarTorn)

A character is more than their skills – they have special powers too! Environments play a key role in determining the PowerCost of a power.


  • A Power consists of
    • A Name and story flare
    • A environment that allows the Power to Be Used
    • A skill That the power uses
    • A goal that the power is trying to acheive (one of the 7 above)
    • A PowerCost consisting of Environment Occurrence +Goal Occurrence (ways to lower discussed later)

Example Powers, Using Environment To Limit

In Tune with Nature: in Any wild (4) can use compassion to commune with the environment allowing a d6 to be rolled and subtracted from the d20 result when scouting (1) (this power allows compassion to be used with scouting, which is not typical)

This power would have a cost of 5.

City Brawler In any Urban(2) or Dungeon(4) can use strength to Attack (2) or Defend (2) allowing a d6 to be rolled and subtracted from the d20result.

This Power would have a cost of 10

Tinkerer – In any Civilized (8) can use scraps and the engineering skill to build an object in order to Produce A Factor (1), that gives a -2 to a future action

This Power would have a cost of 9

Powers can allow a Skill to be used for a goal that is outside its usual set of goals. There is no extra cost to do this, but any power is associated with a single skill only. As we will see later more valuable skills cost more skill points to buy.

All-Environment Powers or Limited Use Powers

Some powers can be used in any environment, but are limited in how frequently they can be used. These will have a large initial cost (12Occurance for any environment +Goal Occurances)!!!

You can reduce the cost of an all-environment power by having a limit on the number of uses. The cost reduction is equal to 12/(1+#ofUsesPerSession)

So if a power can be used in any environment, but only twice a session you would calculate 12/(1+2)=4. If the power has a goal with an occurance value of 2, the final cost of the power would be 12(any environment) +2 (goal of occurrence 2) -4, for a final value of 10. If they limited to once per session it would have a cost of 8.

If you want to avoid Math:

Uses per Game SessionDecrease in Cost (12/(1+x))

Another way is for a character resource (such as HP or Energy) to be expended by using the power. In this case the cost of the power decreases by the chart below:

Resource ExpenditureDecrease in Cost – (X/12)*10 Rounded Down

So a power that can be used in any environment (12) + For a goal of occurrence (4) but requires an expenditure of 6 energy would have a final cost of 12+4-5 or 9.

Building Characters

  • To determine Skills stats roll 4d6, keeping highest 3, or use a point buy of 10, 12 or 14 (based on GM’s desired difficulty) * number of skills*Value of average skill rounded down. Our hypothetical GM above has an average skill value of 3 and 10 skills. So players would have 360 skill points to buy skills, if GM used the base 12 option.
  • Players must have a score of at least 3 in each skill. Max skill value is 16. Only 2 scores max can have a score of 3.
  • From a bank of 20, 30, 45, or 50 (based on desired power level) invent Powers.

Optional Rules


Eliminate the Build a Factor goal and instead a character can spend a point of energy to have another character assist them (they also spend a point of energy). One character rolls, both share in consequences.

Power Ups

Special equipment costs wealth. In general gear costs [bonus(subtracted) the gear gives] + [SkillValue of skill used to use gear] + [Occurance of Goal Equipment is used for]

Lovecraftian Example

A GM wants to run a short Lovecraftian campaign. He decides on Environments

  • Urban – Occurrence 6
  • Aquatic (including beaches, boats, wharfs and on or under the sea) – Occurrence 4
  • Forest – Occurrence 2.

The derived occurrences would be Any (12, as always), or in Nature (Aquatic + Forest for an Occurrence of 6)

For Goals

  • Investigate – Occurrence 4
  • Survive [replacing combat has you cannot damage lovecraftian horrors, at least not directly] – Occurrence 3
  • Solve a Problem – Occurrence 2
  • Build a Connection – Occurrence 3

He decides that scouting and building a factor will not be used mechanically.

He decides that the skills will be

  • Strength – Solve a Problem – Skill Value 2
  • Dodge – Survive, for physical threats – Skill Value 3
  • Will – Survive, for mental threats – Skill Value 3
  • Thievery – Solve a Problem and Investigate – Skill Value 6
  • Archaeology – Investigate and Solve a Problem – Skill Value 6
  • Arcana – Investigate – Skill Value 4
  • Psychology – Build a Connection – Skill Value 3

He has 7 skills and an average skill value of 3. He decides that lovecraftian characters should be outgunned so he uses a base of 10. Thus each character can spend skill points of 3 x 7 x 10 for 210 Skill Points.

He decides to give characters 20 points to build powers.

Starting HP will equal Strength or Dodge. Starting Sanity will equal Will or Psychology. This allows him to add some ‘value’ to skills with lower occurances

Sarah decides she wants to play a Ship Captain who has seen unspeakable evils.

She wants her character to be tough, so she decides on a Strength of 14 (costs 28) and a Dodge of 14 (costs 42) that spends 70 skill points, with 140 remaining. She decides to have her character be weaker at Archaeology and Psychology and assigns them a score of 8 each costing 24+48=72 points. Thus 68 points remain

She puts 10 in will (38 points remain)

She puts 4 in Thievery (a true dump stat. 14 points remain)

And another 3 in Arcana (2 points remain)

With the final 2 points she boosts strength up one more point.

She realizes her character will be great at fighting but weak at investigating. So she decides on her first power:

Captain’s Hunch In any Aquatic Environment(4) when the captain uses Archaeology to investigate (4) she get a bonus d6 that is subtracted

She has 12 points left to build more powers

She decides she wants a limited use power for survival

Sea’s Grit I any environment (12) when using Dodge to Survive (3) the captain can get a bonus d6 that is subtracted, but this power can be used only three times per session (-3). Final cost is 12.

These powers bring out the aquatic focus of her character, as well as her raised-by-the-sea scruffiness.

Reminder to GMs

If you assign a Occurance of 4 to an enviornment, that environment needs to have one third (4/12) of the evidence points! You do not need to be exact, but players will feel cheated if something that was supposed to have a high occurance in the game world does not prove to be that relevant!


My RPG Under a Hostile Sun has recieved interest from my players. Hopefully late August / Early September (I am going on vacation in August) we will get a playtest together on that. In the meantime I will continue to refine Hostile Sun and this Ark-12 system. When its ready, I plan to CC license.

Photo by Timothy Dykes on Unsplash

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