Combat rules

The Martial Pool

The Martial Pool is the core of the Codex Martialis fighting system. Each turn, you literally hold your options in your hand, with your dice. It’s up to you how many you allocate to attack, defense, movement, or other acts of desperation or calculation. You alone determine whether to use single dice for repeated attacks, or combine multiple dice in a ‘roll many/keep one’ die roll to improve your odds, or to keep some dice in reserve for defense or other contingencies. The range of options is a fluid continuum from total attack to total defense, with many other possibilities in between.

Acquisition of Martial Pool

Martial Pool can be accrued by a character or NPC one of two ways – either by adapting a character from some OGL system, or by using the Codex Martialis Character Generation rules (see Codex Integrum Player’s Guide: Char-Gen Rules). When adapting an OGL character, as a default rule of thumb, you can give PCs one MP per fighter (or equivalent) level, and one MP per two levels in other classes. For Codex rules see Prowess under Basic Combat, below.

Using The Martial Pool

In the Codex Martialis you don’t get a fixed number of attacks per round. Instead you have a Martial Pool (MP) which consists of a number of dice. These dice may be used to make multiple attacks, to enhance the effectiveness of one or more attacks, or for Active Defense (see Basic Combat). The value of the MP reflects the number of 20 sided dice you can use in combat in one round. You can literally hold your MP in your hand at the beginning of each round.

The Martial Pool accrues at the rate of one die per point of Prowess, plus one. Prowess means your baseline To Hit bonus. This is similar to what was called BaB in 3.5x OGL, and analogous to Proficiency in 5x. The minimum MP is 1, the maximum MP is 4. For example, a character with a Prowess of +2 would have three MP. A character with a Prowess of +3 would have four MP. A character with a Prowess of +6 also still has an MP of four because the maximum is four.

How you spend the dice in your Martial Pool is part of your individual strategy. Assuming you have an MP of 4 (or better), do you make 4 separate attacks? Do you make one enhanced attack with all four dice (see Basic Combat, Attack)? Do you use one die for attack and save three dice for Active Defense, or use one for movement and save the rest for a counter-attack? It’s up to you to decide. You create your own strategy to suit your Character’s fighting style and the circumstances of the moment.

Using the Martial Pool to manage risk

When rolling multiple dice, a natural 1 (see: Fumbling) is ignored so long as another higher die roll was also rolled, and a natural 20 (see: Critical Hits, Counterattacks) is always considered a success since you take the best die roll. When rolling only one die a natural 1 is always considered an automatic fumble.

Using the Martial Pool on Saving Throws

Dice in the Martial Pool may be applied to Saving Throws as well as attacks or Active Defense. They are used the same way except that any Pool dice expended on a Saving Throw are pooled with the normal Saving Throw roll. In other words, you always get at least one die for any Saving Throw; adding MP dice gives you a way to improve your odds

Balancing Offense & Defense

When using the Pool it’s simply a matter of choosing how many MP dice you wish to put into moving, attacks, movement, and Active Defense, and this can be all attack or all defense or anything in between as you see fit.

Martial Pool and Movement

Using the Martial Pool also requires a slight change to the standard OGL movement rules. You can make one free movement per round up to each PC or NPC’s movement rate (i.e. 15’-30’). Each subsequent movement after the initial move requires the expenditure of 1 MP, up to a maximum of 3 movements (this is separate from changing combat range in a fight, for that see Changing Range). To Run (4 movements) the PC must expend all available MP (i.e. none can be assigned for Attack or Active Defense) or to Charge (see Advanced Rules, Charge). If a Character has less than 4 MP, they can still run (at 4 x standard movement rate) by expending all available MP on movement (i.e. no combat).

Entering or exiting combat range (anywhere threatened by an Opportunity Attack) also costs 1 MP. This makes PCs and NPCs (as well as animals and monsters) a bit more mobile than low level NPCs which should be kept in mind, it also allows more natural range from no movement / total combat (the Full Attack option) to all movement / no combat.

Basic Combat

Combat breaks down into a series of options. You determine initiative to see who goes first. When it’s your turn, you decide whether to attack, defend, or move. The fight takes place at three ranges – onset, melee and grapple. Your strategy will determine where and how you fight.


Initiative determines who strikes first in a fight, a critical factor in any fight and in the strategy a Player implements in combat. This works like normal. (However for more on initiative and options see the optional rules.)

Long Weapons give Initiative Bonus

In real life, a longer reach gives a major advantage in the opening stages of a fight. To represent this, if you begin a fight with a weapon in your hands, the Initiative Bonus is equal to the Reach To-Hit Bonus with that weapon (for melee weapons) or the Close range To-Hit Bonus (for missile weapons). Whenever you roll for Initiative you should apply this bonus.


Codex Martialis gives the PC and GM alike several new options for the Attack. The characters Prowess (or Proficiency) bonus is combined with either a Reach or a Speed bonus from the weapon itself. An unarmed attacker is considered to have a Reach bonus of 0 and Speed bonus of 6.

Using Multiple Die Rolls for One Attack

You can use two or more dice from your Martial Pool on the same attack in order to increase your odds of a hit or a critical hit. To do this simply roll all the dice selected; keep the highest roll and discard the rest. For example, you may choose to use all four dice in a single attack. You roll a 4, an 11, a 6 and a 17. You would keep the 17 as your roll and discard the others, and you have now expended your entire MP for this round.


Prowess is the Codex term for what was called BaB in 3.5x and what is called Proficiency in 5x. It is a die roll bonus representing the basic fighting ability of the character, and is acquired via Class Levels. Unlike the other concepts from the different versions of OGL, Prowess applies both to attack and defense die rolls, but not to skills. If you prefer to use one of the other similar concepts from the OGL, feel free to do so.

Multiple Attacks

You can use two or more dice from your Martial Pool on the same attack in order to increase your odds of a hit or a critical hit. To do this simply roll all the dice selected; keep the highest roll and discard the rest. For example, you may choose to use all four dice in a single attack. You roll a 4, an 11, a 6 and a 17. You would keep the 17 as your roll and discard the others, and you have now expended your entire MP for this round.

Combat Ranges: Onset, Melee, Grapple

We can think of combat as taking place at three ranges: onset, melee, and grapple. All missile combat takes place in the onset range. The first melee attack of a fight also takes place in the onset range. All attacks made in the onset range gain a To Hit bonus based on weapon reach. Attacks in the melee range are based on speed. Subsequent attacks in the same round are considered at melee range unless you are Maintaining range (see below):

The First Attack

Your first attack in a fight is almost always in the Onset range. In the Onset Range, your weapons To-Hit Bonus is based on Reach.

Follow-up Attacks and Melee Range

Your second and subsequent attacks in the same round are usually considered to be in the Melee Range. Weapon bonus is based on Speed. All counterattacks are also based on Speed (unless you are ‘maintaining range’ by using multi-die attacks).

Maintaining Range

As long as you make no followup attacks or counterattacks you are considered to still be in Onset Range at the beginning of each round. Once either combatant has made a second attack in the same round you are considered in melee (or grapple range). The only exception to this rule is that it is possible to execute two attacks while maintaining range by committing two dice to each attack (thus leaving none for Active Defense). Normally this would mean that you will have no MP remaining for Active Defense.

Grapple Range

To enter Grapple range one must make a successful attack either unarmed or with a size S or T weapon. Once the PC announces their attack and intention to enter Grapple, their opponent may first make an Opportunity Attack (OA) if they have dice remaining in their Martial Pool. If there is no OA or the PC survives the OA and the PC hits with their attack, they are now in Grapple range. Note: it is possible to be at grapple range with one opponent and onset or melee with another.

While at Grapple Range, Weapon Defense Bonus no longer applies for active defense and Weapon Reach does not apply to attacks, but Speed does. Being at Grapple range does not mean that grappling is necessarily taking place.  Exiting from Grapple range requires the expenditure of one die from the Martial Pool, and provokes a potential OA.

Fighting in Grapple Range

Once in Grapple Range, there are four special effects:

  • The Weapon Defense Bonus no longer applies.
  • Weapons sized M or larger cannot be used to attack (except for special cases).
  • Shields confer passive defense only (see Shields).
  • All weapons receive their Speed To-Hit Bonus instead of their Reach To-Hit Bonus.

You can change range one step (from grapple to melee or melee to onset or vice versa) for the expenditure of one Martial Pool Dice. Move equivalent actions (any actions which could draw an Opportunity Attack) may require expenditure of one to two Martial Pool Dice at the GMs discretion. Entering or leaving Grapple range may trigger an OA, though some Martial Feats trump this (See Martial Feats).

Opportunity Attacks

Are not automatic extra attacks in Codex Martialis. Executing an Attack of Opportunity requires that dice be available in your Martial Pool.

Deciding how to attack

Whether you’re attacking with one dice, or many, there are several options on HOW to attack.

Attack Types
Critical Hitsd10d8d6d6

Armor Bypass

Thrusting into the opponent’s visor in a tournament, from the Freydal manuscript, circa 1512

Armor can either be penetrated (by overcoming Damage Reduction) or bypassed. Bypassing an opponent’s armor means striking them in such a way that the blow slips past their armor. To bypass armor, the attacker must apply the Bypass Penalty for the particular armor type. Depending on the type of armor this can be anywhere from -2 to -10. Natural Armor is always -10 to bypass. If a hit is scored in spite of the Bypass Penalty no Damage Reduction is applied for the armor. See Armor for more information on the Bypass Penalty.

Attacking Armor

In some cases, when using certain types of weapons against certain types of armor, armor which cannot be penetrated can be ablated. You simply announce your intent to attack the armor instead of the person or creature wearing it. This can be done against natural armor as well. Any hit does damage to the armor. Hardness is deducted as Damage Reduction and any remaining damage is applied against the armor’s Hit Points. Once the armor has been reduced to 0 or less hit points it offers no further DR until it is repaired. Repair requires the skill of someone with suitable expertise and equipment.

Using Weapons Two-Handed vs One-Handed

One Handed Weapon (1H)Hald-and-a-Half Weapon (HH)Two-Handed Weapon (TH)
Wielded One-Handed+1 Reach
-1 Speed-2 Speed
-1 Defense-2 Defense
Wielded Two-Handed-1 Reach
+2 Damage

Determining if an Attack is Successful

Attacks are resolved by first determining if the attack successfully hit the target.

Calculating your Defense Bonus

Your Base Defense value is equal to your Prowess plus your Dexterity Mod. Both Active and Passive Defense are based on your Base Defense value. All PCs and NPCs receive a Defense Bonus (DB) based on their Prowess. For example, a third level Soldier with a Prowess of +3 also gets a Defense Bonus of +3.

Defense against Missiles

Your weapons Defense bonus does not apply in Active Defense against Missiles (unless you have the Missile Parrying MF), but your shields Defense bonus does. When defending against missile attacks cover may also play a role (one Free Dice for Active Defense for every 25\% cover) Other than that your defense against Missiles is the same as defending against a melee attack.

Undefended Targets

Undefended targets have a Passive Defense value of 2 vs melee weapons (roll dice for Critical) and are considered to have a Passive Defense value of 8 against missile weapons.

Deciding to defend active or passively

You can engage in Active or Passive Defense with the Codex Martialis.

Passive Defense

Passive Defense means you are relying on your reflexes, distance and training to react appropriately to enemy attacks. For Passive Defense you simply add 8+ all applicable defensive bonuses. The attacker must roll higher than your Passive Defense score. For example, an unarmed 1st level Soldier (Prowess 1) with a 13 Dex (+1) would have a Passive Defense of 2+8= 10. Normally weapon defense does not apply to Passive Defense (some Martial Feats trump this, see Martial Feats), but Shield Defense always does apply.

Active Defense

Active Defense means that you are paying special attention to actively trying to defend yourself. When you are attacked any dice available in your Martial Pool can be used for Active Defense. You roll a d20 and add that to all of your defensive bonuses for Dexterity, Weapon Defense, Prowess, Feats, and so on where applicable. If you roll a natural 20 you are eligible for an immediate Counterattack if you have dice remaining in your MP (see Counterattack).

Generally speaking, the odds are slightly better for Active Defense. Also you have extra opportunities for a Counterattack with an Active Defense. However, there is also considerably more risk.

Determining the Outcome of an active defense

Extra (Active) Defensive Die Roll for Shields.

If used for Active Defense shields automatically generate an extra defensive die roll every time they are used, but this must also be matched by at least one die from the shield bearer’s Martial Pool. This can be combined with any other Active Defense die rolled normally. It does not have any effect on passive defense. Using a shield Actively always forces the allocation of at least one MP die.


Any time the Defender rolls a natural 20 in Active Defense then they may perform an immediate counterattack with any remaining dice in their Martial Pool (see Defense). In the event that you roll a 20 in Active Defense and the attacker also rolls a 20 you can still Counterattack. Any resulting hit would be considered to have occurred simultaneously with the attacker’s hit. A Counterattack is also triggered if the attacker rolls a natural 1 against any Active Defense. A natural 1 against a passive defense is a fumble (usually meaning a dropped weapon or equivalent mistake at GM’s discretion)

The Tie that Binds

When the attacker and defender roll a tie (on the dice that counts), they enter a Bind.

Tie roll defending against missiles

If the Attacker and Defender end up with a tie roll during a missile attack, it’s a very near miss.

Tie roll vs. Passive Defense

A die roll value which is equal to the targets Passive Defense is a Miss, but it also counts as a Bind. Either attacker or defender can declare a Bind if they have any MP remaining.

Desperation Defense

If you are attacked while using Active Defense, and your opponent scores a hit, you may expend any remaining MP you have to make another Active Defense roll. If you have the initiative advantage you must then swap initiative values with your enemy (effective next round). If you do not have the Initiative, you lose one MP on your next round.


A tie on any die roll that counts is considered a “Bind”, and can trigger certain Martial Feats (See Martial Feats) as well as opportunities to seize or disarm your opponents weapon.  This means the physical die roll, not the modified die roll.  If you are using the optional rule Damage to Weapons During Binds the attacker has potentially damaged the defenders weapon. (On the other hand the Fuhlen MF confers immunity from your weapon being damaged in a bind.)

If you re rolling a multi-dice attack, you may choose which die roll to pick as your die that counts (it doesn’t have to be the highest number) so it is possible to pick the die roll which gives you a tie and therefore a bind. (It would also be possible to pick a natural 1 if for example you wanted to intentionally lose a fight for some reason.) If both attacker and defender are using multiple dice, the person with the initiative decides who declares first.

If two opponents both have MF triggered by a Bind, such as for example if the attacker has Mutieren MF but the defender has Bind \& Strike MF, these attacks take place simultaneously.  Alternately if you prefer a less ‘bloody’ system you can allow the person with the initiative to go first.

Binds do not count when the defender has elected to ‘void’ in their active defense (i.e., there is no bind if they did not count their weapon or shields defensive value).


Shields are treated like special defensive weapons; they have a Defense Bonus like weapons do which can be applied to Active or Passive Defense. Some feats allow shields to be used offensively as well. Normally when fighting with a shield, either the weapon’s defense value OR the shields defense value is used to calculate Active Defense (whichever is higher). Keep in mind that a shield always gains a “Free Dice” in any Active Defense roll. The DB of a shield is also automatically added to Passive Defense, unlike the weapon’s DB. Certain Martial Feats allow you to combine the DB of your shield with that of your weapon (see Martial Feats).

Shield Damage

On any bind (tie roll) against an Active Defense roll with a shield the shield has been potentially damaged. Roll damage for the attacking weapon, subtract Toughness value as a DR, and apply damage to the shield appropriately. A shield used for Passive Defense may also be targeted for attack like Armor (see Attacking Armor).

Critical Hits

Critical Hits represent extraordinary damage caused by any attack. A natural 20 is always considered a hit, but is only a Critical Hit if the modified roll is higher than the defenders roll (if any).  So for example if you are at -5 To-Hit, and roll a natural 20, and your opponent is at +5 and rolls a 19, it’s a hit, but it’s not a Critical Hit. Critical Hit damage is special for Bludgeon Weapons (see below). Crit Damage is a D6 for Bludgeon and Piercing, a D8 for Chop attacks, and D10 for Slash attacks, regardless of the weapon. Basic damage and Critical Hit damage is always combined for purposes of Damage Reduction.  Alternately, if you prefer a simpler system simply make all critical hits cause D10 damage or double damage.

Dynamic Criticals

When attacking with the Primary attack type for your weapon, and using multiple attack dice in a single attack, damage is one die per MP rolled. So a Critical Hit scored in a 3 dice slash attack with a Katana would cause 3d10 damage, a 2 dice chop attack 2d8 etc.  (Note: it is only a Critical Hit if you meet the criteria above, i.e. it has to not only be a natural 20 but also higher than the defenders roll, if any.)

Attack Types and Critical Hits

The Primary Attack type(s) listed by weapon represent the types of attacks for which the weapon is most suitable and the only means by which the weapon can cause a Dynamic Critical. For example, a sidesword is capable of the attack types Slash, Chop, and Pierce but only Pierce and Slash are listed as the Primary Attack types. So you can Chop with this weapon but if you make a multi-die Chop attack and a natural 20 is rolled your Critical Hit will only cause 1D8 Damage. If a Critical Hit is indicated in a Piercing attack however, it is considered a Dynamic Critical.

Bludgeon Damage and Bludgeon Critical Hits

Bludgeoning weapons are more likely to cause basic damage as less finesse is required to break bones or crush organs than to properly cut or pierce an opponent. Critical Hits from bludgeoning weapons are handled differently. A Critical Hit from a Bash attack is treated as a potential Knock Out (KO). This can be handled one of two ways:

Nonlethal Damage

Critical Hit damage is rolled normally, and is applied as nonlethal Damage per standard OGL rules.

Knock Out Threat (Optional Alternative)

Critical Hit damage is added to Basic Damage and the two values are combined into a Knock Out threat. This becomes the TN for a Will save (see KO Table, Appendix II: Weapons) If the target fails the save they may be knocked out or stunned.


A natural 1 on an attack die roll is automatically considered a fumble and may indicate a counterattack by your opponent. (see counterattack). A natural 1 on an Active Defense die roll means an automatic hit by the attacker. The only time a natural 1 can be ignored is if you rolled multiple dice in the same roll (using the Martial Pool), in which case it can be discarded in favor of a higher die, unless all dice in the pool come up 1 of course.


Armor works as Damage Reduction. Armor does not affect Defense except detrimentally by reducing the Maximum Dexterity bonus (Max Dex).

New Weapons & Armor Characteristics

Melee Weapon Characteristics

The characteristics of the weapon you wield plays a role in the strategy you use in a fight. Large weapons have better reach, small weapons are faster. Piercing weapons are more effective against armor, while slashing weapons are better against unarmored opponents.

Reach To-Hit Bonus

Each melee weapon has a Reach To-Hit Bonus (RTHB) which comes into play in all opening attacks. Longer weapons such as spears, staves, lances, and pikes all have excellent reach. Initial attacks use the RTHB. See Basic Combat, Attack.

Speed To-Hit Bonus

Each melee weapon has a Speed To-Hit Bonus (STHB) which comes into play in all follow-up attacks. Daggers, hatchets, knives and short-swords have good speed. Weapons balanced by an iron pommel, such as broadswords or arming swords, have better speed than those which don’t, such as a hatchet or a mace. With certain Martial Feats, double-edged weapons can have a speed advantage as well. Any time you attack for the second and subsequent times in a given round, and any time you make a Counterattack or an Attack of Opportunity, you use the STHB of your weapon. See Basic Combat, Attack.

Weapon Defense Bonus

Each melee weapon is rated for defense. Shields and weapons which are of a substantial size but well balanced have a good Weapon Defense Bonus (WDB). Most swords, maces, and certain daggers have good defensive characteristics, as do staves, spears, and pole arms when used with two hands. Weapons with extra hand protection also have a higher WDB. See Basic Combat, Defense.

Damage Rating

The Damage Rating value represents the normal damage done for any attack.

Armor Piercing Bonus

Certain weapons are designed specifically to pierce armor. These weapons receive an Armor Piercing Bonus. This bonus lowers the Damage Reduction value from your opponent’s Armor (see Armor).

Attack Types

Each weapon has one or more Attack Types. The different Attack Types are Chop, Slash, Bash, and Pierce.

Primary Attack

The Primary Attack is the Attack Type which is used for Critical Hits. For example, a dagger may be able to Slash and Pierce but the Pierce Attack Type is considered the Primary Attack type as it is the one that may cause a Dynamic Critical (see Critical Hit).


This is the standard damage inflicted by this weapon during a normal attack. Basic damage is sometimes lower for weapons which can cause multiple forms of critical hits. Bludgeon weapons tend to have higher basic damage since Bludgeon critical hits do not cause extra killing damage, and because it (arguably) takes less finesse to cause damage with a blunt instrument than with an edge or a point.

New Armor Characteristics

Armor works as Damage Reduction. Armor does not affect Defense except detrimentally by reducing the Maximum Dexterity bonus (Max Dex).


Cost is somewhat arbitrary, since many of these types of armor existed in radically different economies sometimes thousands of miles and hundreds of years apart.

Damage Reduction (DR)

If you are not using the “Attack Types vs. Armor” optional rule only the first bolded number counts, otherwise use the second number for DR vs. Chop attacks, the third number for DR vs. Slash attacks.


Armor Bypass is the To-Hit penalty for bypassing a person (or thing… buahahahah) wearing this type of armor.

Armor Check

Armor Check is the die roll penalty for Dex based skill checks when wearing this armor.

Max Dex

Max Dex is the ceiling for your Dexterity bonus to AC and missile weapons or Weapon Finesse etc.




Hardness is the DR of the armor itself if the armor is attacked.

Hit Points (HP)

HP the amount of damage the armor can take before being rendered ineffective.

Minimum Strength (Min Str)

Min Str is the minimum strength required to wear the armor.

Martial Pool and Armor

Any armor with a Max Dex of +1 or less also causes the wearer to lose 1 martial pool (for a minimum of 1 MP per round).

New Ranged Weapon Characteristics

Missile To-Hit and Amor Bypass Modifications by Range
MeleeCloseShortMedLongVery Extreme