Tag Archives: Mass Combat

Mass Combat pt.3


Tactics are options an army can use to inf luence aspects of a battle. A newly recruited army doesn’t know any of these tactics unless specif ied by the GM. An army learns new tactics by being victorious in battle (see Victory, Rout, or Defeat on page 239). An army can know a number of tactics equal to half its ACR, minimum 0.

When a battle begins, the commander selects one tactic to use for that battle (if the army doesn’t know any tactics, the army uses the standard tactic). At the start of each Ranged or Melee phase, the commander may try to change tactics by attempting a DC 15 Morale check. Success means the army uses the new tactic for that phase (and the modifiers from the old tactic cease); failure means the army continues to use its current tactic. The effects of tactics end when the battle does. Continue reading Mass Combat pt.3

Mass Combat pt.2


Mass combat takes place over the course of three battle phases: the Tactics Phase, the Ranged Phase, and the Melee Phase. A phase doesn’t denote a specific passage of time, leaving the GM latitude to determine how long a mass combat takes to resolve. For example, a battle in a muddy field after a rain could take place over hours and involve several short breaks to remove the dead from the battlefield, but still counts as one battle for the purposes of these rules. If there is an extended break (such as stopping at nightfall to resume combat in the morning) or the battle conditions change significantly (such as the assassination of a commander, the arrival of another army, and so on), the GM should treat each period of combat between armies as one battle. The battle phases are as follows.

  1. Tactics Phase: The GM decides what battlefield modifiers apply to the battle. The commanders each select a tactic their respective armies will use during the battle (see page 237).
  2. Ranged Phase: Any army with the ability to make ranged attacks may make one attack against an enemy army. This phase typically lasts for 1 round (one attack) as the two armies use ranged attacks while they advance to melee range, and then use melee attacks thereafter. The battlefield’s shape and other conditions can extend this duration. If both armies have ranged attacks, they may choose to stay at range and never approach each other for melee (at least until they run out of ammunition, though the Consumption cost of maintaining an army generally means the army is capable of many shots before this happens). Armies without ranged capability can’t attack during this phase, but may still rush forward.
  3. Melee Phase: The armies finally clash with melee attacks. Each commander selects a strategy using the Strategy Track (see page 239), then each army makes an attack against another army. Repeat the Melee phase until one army is defeated or routs, or some other event ends the battle.


In mass combat, the hundreds of individual attacks that take place in one battle phase overlap each other enough that who actually attacks first is irrelevant.

When armies attack, each army attempts an Offense check (1d20 + the attacking army’s OM) and compares the result to the target army’s DV.

If the Offense check is equal to or less than the target army’s DV, the army deals no damage that phase.


If the Offense check is greater than defender’s DV, the defending army takes damage equal to the result of the attacker’s Offense check minus the defender’s DV. For example, if the attacker’s Offense check is 11 and the defender’s DV is 7, the defending army takes 4 points of damage. Because these attacks are resolved simultaneously, it is possible that both armies may damage or even destroy each other in the same phase.

If the Offense check is a natural 20, but that check is lower than the enemy army’s DV, the attacking army still deals 1 point of damage. If the Offense check is a natural 1, that army can’t attempt an Offense Check in the next phase, due to some setback: a misheard order, getting stuck in mud, and so on.

Beyond the Kingdom

The mass combat rules often refer to aspects of the kingdom building rules, such as Loyalty checks and a kingdom’s Control DC. If you aren’t running a kingdom, substitute a Will save for a Loyalty check. Instead of a kingdom’s Control DC, use the primary ability DC of a monster with a CR equal to the party’s APL (see Monster Statistics By CR, Bestiary 291). For example, if the party’s APL is 12, the Will save DC is 21. Instead of a kingdom turn or kingdom phase, use 1 month. Instead of BP, multiply the BP cost by 500 gp.

More Than Two Armies

These rules can also serve in battles where more than two armies clash. In such battles, when your army attempts an Offense check, you choose which enemy army (or armies, if you have multiple armies in the field) it is attacking and apply damage appropriately. On each phase, you may change which army you are targeting. If your kingdom fields multiple armies in a battle, you may want to divide responsibility for these armies among the other players to speed up play.


In some mass combats, the specifics of a battlefield won’t impact either army, but sometimes the battlefield will itself decide the outcome. The modifiers listed below apply only for the duration of the battle. Naturally, the GM should exercise judgment regarding any conditions that don’t seem to apply to one of the armies (such as darkness and an army with darkvision, or fog and an army with scent).

At the GM’s discretion, large-area spells such as move earth might allow armies or commanders to manipulate the battlefield conditions before a conf lict. For these spells to have any effect, they must last at least 1 hour and affect at least a 500-foot square. Likewise, magic items such as an instant fortress (+2 Defense) and spells such as wall of stone (+1 Defense) can create simple fortifications for an army to use in a battle.

Advantageous Terrain: Generally, if one army occupies a position of superiority (such as being atop a hill, wedged in a narrow canyon, or protected by a deep river along one f lank), the defending army increases its DV by 2.

Ambush: In order to attempt to ambush an army, the entire ambushing army must have concealment. The ambusher attempts an Offense check against the target army’s DV. If successful, the battle begins but the target army doesn’t get to act during the Tactics phase. Otherwise, the battle proceeds normally.

Battlefield Advantage: If an army is particularly familiar with a battlefield, it’s OM and DV increase by 2.

Darkness: Darkness reduces all armies’ OM by 2 and DV by 3.

Dim Light: Dim light reduces all armies’ OM by 1.

Fog: Fog reduces damage by half and gives the armies a +2 bonus on Morale checks to use the withdraw tactic.

Fortifications: An army located in a fortification adds the fortification’s Defense to its DV. A settlement’s Defense is determined by the types of buildings it contains, as detailed in the kingdom-building rules on page 212. If the game isn’t using the kingdom-building rules, a typical fortification increases DV by 8.

Rain: Rain affects modifiers to OM in the Ranged phase as if it were severe wind; see Table 13–10: Wind Effects on page 439 of the Core Rulebook.

Sandstorm: A sandstorm counts as fog and deals 1 hp of damage to all armies during each Ranged and Melee phase.

Snow: Snow affects ranged attacks like rain, and affects damage like fog.

Wind: The wind modifiers to ranged attacks apply to OM in the Ranged phase; see Table 13–10: Wind Effects on page 439 of the Core Rulebook.

Mass Combat pt.1

Mass Combat

Sooner or later, even the most peaceable kingdom will f ind itself faced with the prospect of war. While some kingdoms at odds with your own might be willing to compromise, others are not amenable to negotiation, or respond to overtures of appeasement with ever-increasing aggression. When diplomacy fails, the clash of steel is close behind.

This section contains rules for you as a kingdom leader to create armies, assign their commanders, and prepare them for battle on land, at sea, or in the skies. This includes rules for equipping and maintaining conventional armies, utilizing PCs as part of mass combat, converting groups of monsters into military forces, and going beyond the battlefield to deal with the aftermath of combat.

These rules provide an abstract, narrative mass combat system that will let you rapidly play out a complex battle scenario without getting bogged down in excessive detail, while still retaining fidelity to strategy, tactics, and the realities of the battlef ield. These rules are not intended to accurately represent complex wars, provide a highly tactical simulation, or accurately model a tactical warfare miniatures game. Instead, they are intended to incorporate warfare into a campaign while still staying primarily focused on traditional, small-scale adventuring and roleplaying.


The key parts of the mass combat rules that you’ll reference often are:

  • Explanations of the army stat block and terminology used throughout this chapter (see below).
  • Step-by-step instructions on how to run the battle phases of a combat between armies (page 236).
  • Battlefield modifiers for terrain and similar factors (page 237).
  • Different tactics that armies can learn (page 237).
  • What happens at the end of a battle, once an army wins, loses, or f lees (page 239).
  • How to use special commanders or kingdom leaders to modify army statistics (page 239).
  • Resources to upgrade and improve armies (page 241).
  • Special abilities for unusual armies, such as spellcasting or poison (page 242).
  • A list of sample armies (starting on page 247).


The description of each army is presented in a standard format. Each category of information is explained and defined on the following pages.

Name: This is the name of the army. This could be a mercenary company’s name, such as “Thokk’s Bloodragers,” a formal regiment number such as “7th Royal Cavalry,” or an informal name such as “militia from Redstone.”

XP: This is the XP awarded to the PCs if their army defeats this army, and is the same as an XP award for an encounter with a CR equal to the army’s ACR (see below).

Alignment: An army’s alignment has no effect on its statistics, and is just a convenient way to summarize its attitude with two letters. It is usually the same alignment as a typical unit in that army.

Size: The army’s size determines not only how many individual units exist in the army, but also the army’s ACR.

Table 4–15: Army Sizes


Fine 1 CR of individual creature –8

Diminutive 10 CR of individual creature –6

Tiny 25 CR of individual creature –4

Small 50 CR of individual creature –2

Medium 100 CR of individual creature

Large 200 CR of individual creature +2

Huge 500 CR of individual creature +4

Gargantuan 1,000 CR of individual creature +6

Colossal 2,000 CR of individual creature +8

Type: This lists the nature of the army’s individual units, such as “orcs (warrior 1)” or “trolls.” These rules assume all units in an army are essentially the same; if an army of 100 orc warriors 1 (meaning 1st-level warriors) actually has a few half-orc warriors or some orc barbarians, their presence has no effect on the army’s statistics. If an army has a large number of units that are different than the typical unit in that army, and these differences are enough to change the army’s stat block, it is generally best to treat the group as two separate armies with different stat blocks.

hp: An army’s hit points equal its ACR × the average hp value of 1 HD of the army’s units (3.5 for d6 HD, 4.5 for d8 HD, 5.5 for d10 HD, and 6.5 for d12 HD). For example, warriors have d10 HD, so an ACR 1 army of warriors has 5.5 × 1 = 5.5 hp, rounded down to 5 hp. Note that only damage from other armies can reduce an army’s hp; a non-army attacking an army is mostly ineffective, though you can treat the attacker as a Fine army if you want to determine the outcome of the attack. As with standard game effects that affect hit points, abilities that reduce hp damage or healing by half (or any other fraction) have a minimum of 1 rather than 0.

Army Challenge Rating (ACR): This is based on the CR of an individual unit from the army and the army’s size, and scales like CRs for monsters. To determine ACR, see Table 4–15: Army Sizes and apply the modifier for the army’s size to the CR of an individual unit in the army. If an army is cavalry, use the mount’s CR or the rider’s CR, whichever is higher. For example, an individual orc warrior 1 is CR 1/3, so an army of 100 orc warriors 1 is ACR 1/3; an army of 500 orc warriors 1 is ACR 3 (4 steps greater than the standard 100-unit army). If a group’s ACR would be lower than 1/8, it doesn’t count as an army— add more troops until you reach an ACR of 1/8 or higher.

Defense Value (DV): This is a static number the army uses to resist attacks, much like an individual creature’s AC. The army’s DV is equal to ACR + 10 + any bonuses from fortifications or a settlement’s Defense score (see page 212).

Offense Modifier (OM): This is a modif ier added to a d20 roll to determine the army’s chance of success, much like an individual creature’s attack bonus. The army’s OM is equal to its ACR. If the army has the ability to make ranged attacks, that’s mentioned here. Melee attacks and ranged attacks use the same OM unless an ability says otherwise.

Tactics: These are any army tactics (page 237) the army has at its disposal.

Mass Combat Quick Reference

These mass combat rules treat armies as if they were individual creatures. Instead of making 100 attack rolls for each side of a battle between elves and orcs, you treat the elf army as one unit and the orc army as another unit, and they battle each other with just one roll each. Instead of the armies taking turns attacking each other, they roll simultaneously. Smaller armies have fewer individual creatures (units), larger armies have more units, and the number of units directly relates to how dangerous an army is.

Use the Mass Combat Army Sheet on page 251 to track the stats of your armies, just as you use a character sheet to track the stats of your character.

Every army has a commander, typically a seasoned veteran, who directs the army’s actions. You can lead an army yourself, making you its commander and providing bonuses depending on your kingdom leadership role (see page 240).

Armies can learn different tactics, such as using reserve archers, forming a defensive wall, or using dirty tricks. An army can use strategies like attacking recklessly and aggressively (much like a creature using the Power Attack feat) or being cautious and defensive (like using Combat Expertise). The army’s commander decides the tactics and strategy used in battle.

Conditions on the battlefield affect the process and outcome of the battle. For example, muddy terrain slows walking armies but has no effect on flying armies; night combat hinders human armies but not orc armies.

Resolving the battle consists of three phases in which the commanders decide on tactics, the armies make ranged attacks (if any), and the armies then close to melee range. They then remain in melee until one side flees or is destroyed.

The following summarizes the key rolls you’ll make when using mass combat:

Offense Check: d20 + Offense Modifier (OM)

Damage Dealt: Offense check result – the defending army’s Defense Value (DV)

Morale Check: d20 + the commander’s modifiers + the army’s Morale score

Resources: These are any army resources (page 241) the army has at its disposal.

Special: This section lists any special abilities (page 242) the army has.

Speed: This number indicates how many 12-mile hexes the army traverses in a day’s march. Marching through difficult terrain halves the army’s speed. Use Table 7–6: Movement and Distance on page 172 of the Core Rulebook to determine the army’s speed based on the speed of its individual units.

Morale: This number represents how confident the army is. Morale is used to determine changing battle tactics, whether or not an army routs as a result of a devastating attack, and similar effects. Morale is a modifier from –4 (worst) to +4 (best). A new army’s starting morale is +0. Morale can be further modified by the army’s commander and other factors. If an army’s Morale is ever reduced to –5 or lower, the army disbands or deserts and you no longer control it.

Consumption: This is how many Build Points (BP) an army consumes each week (unlike most kingdom expenses, this cost is per week, not per month), representing the cost to feed, hydrate, arm, train, care for, and pay the units. An army’s base Consumption is equal to its ACR divided by 2 (minimum 1). If you fall behind on paying the army’s Consumption, reduce its Morale by 2; this penalty ends when you catch up on the army’s pay.

Commander: This entry lists the army’s commander and the commander’s Charisma modifier, ranks in Profession (soldier), and Leadership score. The commander must be able to communicate with the army (possibly using message spells and similar magical forms of communication) in order to give orders or provide a bonus on the army’s rolls.