2d20 Mod Rules Part 3, Combat

This is an intro to the 2d20 mod combat rules. There are many more combat rules that we could go into; Healing, prone, cover, range rules and so on. For the moment I’ll point you to one of the books like Conan, Star Trek, Achtung! Cthulhu or Infinity. What we have here is enough to start with and modify.


Combat follows a straightforward flow

  1. Determine initiative order
  2. Players and NPCs take action
  3. Combat ends

Initiative order is normally players first, then NPCs. GM can spend threat to jump the initiative order, normally at a cost of 1 threat per PC jumped in the order.

C Mod 1.1 Initiative statC Mod 1.2 Initiative roll
PCs and NPCs have an Initiative stat, probably Awareness + relevant skillPlayers and NPCs roll for initiative. This might be a D0 roll against awareness.


Players will have one minor and one major action

Minor actions include:

  • Aim (reroll a d20)
  • Draw item
  • Move (move to another zone, stand up)
  • Prepare (needed for some major actions)

Major Actions include:

  • Assist (make a roll, if successful add successes as dice to ally)
  • Attack
  • Cast a spell
  • Catch a breath (roll will+resilience, D2, success removes stress)
  • Create Trait (skill test vs D2, success creates a new trait)
  • Delay/Ready (take your action when an enemy action triggers it)
  • Sprint  (move 2 zones away)
  • Stabilise (stop another player dying)
  • Skill test

Players can spend a Fortune point for a 2nd major action but the D increases by one.


To make an attack

  1. Choose a target and attack
  2. Make an opposed roll
    1. Melee: Agility+Close combat D1 v opponent  Agility+Close combat
    2. Ranged: Coordination+Ranged combat D1, increased by range
  3. If successful roll damage
  4. Reduce damage by resistance (armor for physical and so on)
C Mod 3.1 Hit locationsC Mod 3.3 Opposed ranged rollsC Mod 3.3 Defense score
Characters have different hit locations with different amounts of armor. Roll to determine hit location and armor.Targets get to roll Agility + Athletics for their defense on a ranged combat rollInstead of opposed rolls for attacks, the defender has a defense score. This is likely 1, but might be 2 for exceptionally agile characters.

Damage and Injuries

If a character takes 5 or more stress from one attack they suffer harm. Each Harm increases the complication range by 1, to a max of 5. If a character is reduced to zero stress they also suffer harm.

When a character has 5 harms they are defeated. If this is mostly physical harm, they are also dying.

NPCs will have different limits for harm. Minions are usually defeated for 1 harm, medium threats might require 3 harms and major threats will have 5 or more harm.

C Mod 4.1 Multiple HarmsC Mod 4.2 Less HarmC Mod 4.3 No Harm(see CC Mod 7.3)C Mod 4.4 Renamed
You have harm tracks for physical (wounds) and mental (Trauma). You might have further tracks for tech or social.The amount of harm you can receive is reduced to 3.You don’t have harm. You are dying at 0 stress.Harms are called injuries or wounds


Extra successes on attacks generate momentum which can be used on special combat momentum spends

SpendCost (momentum)effect
Bonus Damage1Gain an extra combat dice (max 3)
Bonus dice1,2,3As basic rules
Create Trait2Creates a new trait (or removes one)
Disarm2The target drops a weapon or item they are holding
Knockdown2The target is knocked prone
Minor action1Take an extra minor action
Secondary target2An additional target within reach of the target also receives the attack
C Mod 5.1 Threat for MomentumC Mod 5.2 Bonus Major ActionsC Mod 5.3 Re-roll damageC Mod 5.4 further Momentum spends
Players can spend threat as momentum on combat effectsFor 3 Momentum a PC can take an extra major action (D is increased as per fortune)For 1 momentum you can re-roll all of your combat diceThere are other possible momentum spends in combat. 

Attack types and dice

Here are some example attacks:

NameSkill and FocusStress TypeStress DamageQualities and Effects
IntimidateWillpower/Brawn + Persuasion (intimidate)Mental2cd
TrickIntelligence + Persuasion (trick)Mental2cd
Unarmed StrikeAgility + Close combat (Unarmed)Physical2cd
KnifeAgility + Close combat (blades/knives)Physical3cdHidden
SwordAgility + Close combat (Blades/swords)Physical4cdParrying
Great SwordAgility + Close combat (Blades/swords)Physical5cd2H
PistolCoordination + Ranged combat (pistols/handguns)Physical4cd
RifleCoordination + Ranged combat (Rifles)Physical5cdPiercing 1
ShotgunCoordination + Ranged combat (Shotgun)Physical5cdArea 1
Heavy PistolCoordination + Ranged combat (pistols/handguns)Physical4cdVicious 1


Effects give greater variety between attacks. When an effect is rolled it causes 1 stress damage and triggers the effects for an attack/weapon.

  • Area – the attacks hits an extra nearby target for each effect rolled
  • Backlash X – each effect inflicts X stress on the attacker
  • Intense – if a harm is inflicted, two are inflicted
  • Piercing X – X resistance is ignored before inflicting stress
  • Vicious X – Each effect inflicts and extra X stress
C Mod 6.1 RenamedC Mod 6.2 more EffectsC Mod 6.3 Old CDC Mod 6.4 Effects don’t deal damageC Mod 6.5 No combat dice, no effects
Combat dice might be challenge dice or conflict dice or special dice.There are many more possible effectsInstead of 2 effects, use the original cd with only one effect. If doing this you may need to increase the damages of weapons.Effects don’t deal damage, only 1s and 2s. If choosing this weapons should have base damage (1+2cd)You don’t use combat dice at all, and therefore do not have effects

More Combat rules

There are many more combat rules that we could go into; Healing, prone, cover, range rules and so on. For the moment I’ll point you to one of the books like Conan, Star Trek, Achtung! Cthulhu or Infinity.

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