Codex Martialis

Codex Martialis
RPG published by
Ire Games
Rule System d20 System
Authors Jean Chandler
First Publication 2010
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Codex Martialis, or CM for short is an alternative combat system for d20 games (e.g. D&D). It was created by Medieval & Renaissance Martial Arts fans who wanted to cram their hobby into Dungeons & Dragons without turning it into something as complex as The Riddle of Steel.

All in all, the rules live up to that aim, however being produced on a shoestring budget, it lacks the polish and coherency one associated with professional OGL products. The rules are also quite vague on the handling of magic and magic powers. The creators themselves have admittedly focused on a product more suited to low-magic settings.

Two sourcebooks were also released, Weapons of the Ancient World I & II, describing and adapting existing real world historical pieces of arms and armor for their system. These two volumes might be of interest to all historical role-players, as they contain a comprehensive wealth of lore unlike anything else on the market.


Four new 'mechanics' are introduced:

  1. A martial dice-pool of four d20 dice (MP):
    • You have four d20 dice, which you must 'spend' various actions, from attack & defense to movement and attacks of opportunity. (Certain MFs - see below - provide extra dice for certain actions).
    • If you've assigned more than one die to a task that can be rolled on, just roll all dice and take the highest roll.
    • When rolling multiple dice a natural 1 is ignored so long as another higher die roll was also rolled, and a natural 20 is always considered a hit since you take the best die roll.
    • The pool grants an easy mechanic to set a 'stance':
      Do you focus on attacks, hoping to kill the enemy before he could attack you in return?
      Do you focus on defense, making the enemy expend his pool and make him an easier picking for your allies?
      Maybe you just want to hang back, and look for such attacks of opportunity?
  2. Revamped to hit and damage mechanics:
    • Armor provides damage reduction (DR), not armor class (AC). Bypass is a new armor stat reflects how much armor covers, instead material hardness.
    • The DR of armors can be bypassed at a to hit penalty equal to the armor's Bypass value. (This reproduces values close to traditional AC).
    • Your Base Attack Bonus (BAB) is added to your AC as a Defense Bonus.
    • Defenders can use either active or passive defense.
      Passive defense uses the fixed value of 8+bonuses, or 8+BAB+DEX Mod+Weapon/Shield Defense most of the time.
      Active defense uses a rolled d20+bonuses, or d20+BAB+DEX Mod+Weapon/Shield Defense most of the time. You can roll more than one die on this roll, but all the dice come out of your MP.
      On active defense, shields provide an extra d20 die beyond their defense bonus and a Natural 20 grants an automatic counterattack to the defender.
    • A tie on any die roll that counts is considered a “Bind”, and can trigger certain MFs as well as opportunities to seize or disarm your opponents weapon.
    • Weapons have four new stats: Reach, speed, defense and armor penetration (AP). At the different ranges of combat you use either weapon reach or weapon speed as a bonus to your BAB.
    • Weapon Focus and Weapon Finesse feats scope has been greatly expanded, you can use the same feat for all weapons similar in make and use.
    • If you roll a Natural 20, or take a -10 to hit penalty and would hit normally without the automatic hit effect of the 20, you score a critical hit.
      On a critical hit, your damage is multiplied as many times as how many dice you expended on the attack.
      Since CM recommends using a low HP ceiling of 3xCON for martial and 2x CON for non-martial classes, it's possible to be killed in a hit or two, meaning all combatants must be on their toes even at higher levels.
  3. Combat is divided into three ranges:
    • At Onset, weapon reach and therefore pole-arms dominate. All missile combat takes place in the onset range. The first melee attack of a round also takes place in the onset range.
    • At Melee, closer in, weapon speed takes over, so shorter weapons, like swords fare better. Follow-up attacks (your 2nd, 3rd, etc.) attacks in the same round are considered at melee range unless you are Maintaining range.
    • At Grapple range, while weapon speed is still important, combatants are so close that weapons can no longer be used defensively. Unless you have special training you can only use small or tiny weapons like daggers or knives. Being at Grapple range does not mean that grappling is necessarily taking place, but you're close enough to start it any time.
  4. Introduction of so called "Martial Feats" (MFs):
    • Character gain an MF, every time their BAB goes up by a point, and can be taken in place of normal feats.
    • MFs try to model real world fighting maneuvers.
    • MFs provide a bonus of some sort, but can only be used in specific situations and with specific weapons.
    • Some MF examples:
      • Counter stroke: Prerequisites - Dodge, Weapon Focus with weapon to be used, Benefit - Gain an automatic counter attack against a your designated dodge target if they attack you. This can be very useful if you lost initiative.
      • Feint: Prerequisites - 2 ranks in either Bluff or Intimidate, Benefit - After a contested skill check, at expense of 1 or more MP, draw off one of your opponents Martial Pool, plus 1 per MP expended, which could be a Counterstroke or Meisterhau counterstroke.
      • Meisterhau: Prerequisites - Weapon Focus feat with two-handed cutting weapon, Benefit - you may attempt to make one ‘perfect’ strike, designed to simultaneously bat aside your opponents weapon and strike him. Your modified Attack roll is used in place of your Defense roll against the next attack from this same opponent if that attack is made within one round.
      • Half-sword Fighting: Prerequisites - Weapon Focus with any sword or similar sized staff weapon which can cause Piercing damage, Benefit - +2 AP, you can use your weapon even at grapple range, except for chopping attacks, Restrictions - You loose your weapon's Reach bonus while halfswording, and might injure yourself on a fumble (Natural 1) unless you're wearing mail lined gloves.