The Cortex System is based on the Sovereign Stone System - a plot point rules light system.

Uses D2 to D12 where attributes and skills are assigned a die type (e.g. Strength D6 or Guns D10)

Character Creation

Task Resolution

Roll die for attribute + die for skill and add together to compare against difficulty.

Special character abilities called Assets and Complications are given to characters for bonuses and penalties.

There are also Plot Points which give players influence over events in the game by giving them an extra die, reducing damage or making narrative changes to the storyline. Characters start with 6 and can have maximum of 12.

If both dice rolled result in "1" it is a botch, while if difficulty beaten by 7+ it is an Extraordinary Success.

Combat Resolution

Initiative order is used with one action each turn.

Damage is handled as either: Basic, Stun or Wound, where Basic is both stun and wound damage together. Stun leads to unconsciousness and Wound leads to death.

An attack can be defended against with an action as a normal skill roll, an Agility roll if in combat or 3 if easy unaware target.

Damage is primarily determined by how much you beat the difficulty, but weapon stat adds damage to that result. Basic damage is split between Stun and Wound.

Character Development

1-4 advancements points are awarded per session on average and can be spent on attributes, traits, and skills costing 16, 14, and 6 points respectively.


Has psionics.

Publishing Company

Margaret Weis Productions, Ltd.


Earlier games no longer listed on Margaret Weis website and so likely using older version of the PDQ rules:


  • Jamie Chambers

Also credited on the Margaret Weis website for "collaborative efforts":

  • Cam Banks
  • Nathan Rockwood
  • Floyd Wesel
  • Jennifer Brozek
  • Digger Hayes
  • Jim Davenport


System Analysis



House Rules


Cortex is noted by Steven Lindsey in the RPGNet review of being like a blending of ideas from Savage Worlds and Unisystem.

Noted in Game Geeks Kurt Wiegel's review that probability curve is unusual because of the two dice mechanic used, but once you get used to that it is a light, fun system.

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