Mass Combat: Gridless

In the d20 system, combat involving more than one or two dozen participants often becomes very lengthy, with each combat round taking an hour or more to complete due to the large number of actions being performed, and the complexity involved. This document defines a mass combat system—that is, combat between a number of opposing factions—designed to expedite such encounters while still giving heroic characters the chance to personally involve themselves in a meaningful way.

These rules were adapted from Savage Worlds (starting on page 104) and the Lord of the Rings (starting on page 238).

Naturally, to model large-scale battles capable of lasting many in-game minutes or even hours, the granularity of actions is much coarser. Players do not dictate every individual action their characters perform as they would in a normal combat scenario—rather, they decide how their character is trying to influence the outcome of the battle. Which army do you support? Do you fight in the thick of the melee? Command and inspire the troops you lead? Sling spells from the sidelines? Target the enemy generals? Or do you cower until the worst is over?

Mass combat basics:

Initial battle setup:

Affiliation: Each hero is affiliated with a specific unit during a particular battle round, though he may change affiliations during the course of the battle as a heroic attack action (see “Decide Heroic Actions” below).

Teaming: Multiple heroes affiliated with the same unit can choose to join forces. However, just because two heroes have the same affiliation does not necessarily mean they are teamed—they must agree to work together, and commit to staying side by side for the duration of the battle round.

Teamed heroes have a number of advantages over solo heroes, but also some drawbacks:

Heroes can alter their team configuration using a complex utility action (see “Heroic Utility Actions” below).

Phases of Combat

Combat is divided into 10 minute battle rounds. The following phases happen each round:

1) Events

Occasionally, during the course of a fight, external events will occur that affect the tide of battle. Here are some examples:

The GM will announce any events at the start of each battle round.

2) Allocate Forces

Each general simultaneously and secretly allocates his unit’s tokens with respect to the enemy units. This allocation identifies the enemies being targeted and represents how the unit will fight during the coming battle round. For example, a human unit with 8 tokens facing three enemy units—lions, tigers and bears—might allocate 2 tokens to the lions, 6 tokens to the tigers, and no tokens to the bears, indicating that 25% of the human unit’s strength will target the lions, 75% will target the tigers, with no offensive against the bears.

These allocations are kept secret until the final modifiers are computed (see “Determine Modifiers” below).

3) Perform Heroic Utility Actions

A hero can perform utility (non-attack) actions, as deemed appropriate by the GM. Each battle round, a hero has 5 simple utility actions with obvious consequences, and 1 complex utility action requiring some GM interaction. Some examples:

Although it is assumed that the hero is taking these actions over the course of the coming battle round, treat the results as going into effect early enough to make a difference during this battle round (see “Make Battle Rolls” below).

A utility action that takes between 1 and 5 minutes always uses the complex utility action. For example, a cleric could cast bless water (1 minute casting time) as a complex utility action.

A utility action that takes more than 5 minutes counts as a lengthy action (see “Decide Heroic Attack Actions” below) and uses the hero’s heroic attack action for the round. A lengthy action that takes 10 minutes (e.g., true resurrection) uses both the heroic attack action and all utility actions for the round.

4) Decide Heroic Attack Actions

Heroes decide how they fight for the round. Possible actions include:

Flow of Battle table: When fighting, roll 2d6, and use the result as follows:

5) Determine Modifiers

Before each unit makes its battle roll (see “Make Battle Rolls” below), the GM determines and totals the appropriate modifiers. These include:

Token advantage: If fewer enemy tokens are allocated against a unit than there are tokens in that unit, there is a token advantage. To compute, first determine the unit’s threat value: the total number of enemy tokens allocated against it. Subtract the thread value from the unit’s strength. If this number is greater than zero, there is an advantage, representing the discrepancy between a unit’s power and that of the enemies engaging it. For example, say a dwarven unit with 17 tokens has two enemy units—orcs and goblins—targeting it, with the orcs having allocated 9 tokens, and the goblins 3. In this case, the dwarven unit’s threat value is 12 (9 + 3), for a token advantage of 5 (17 - 12)—the dwarves are in good shape this round.

Hero contribution: Each attacking hero makes a roll with a DC of 15 + threat value. The type of roll depends on how the hero is attacking—it is often a melee attack roll with their favored weapon, but could be a ranged attack roll, ranged touch attack (e.g., using eldritch blasts), tactics skill check (generals only), stealth skill check (in the case of using the Stealth action above), or other roll as deemed appropriate by the GM. Due to the continuous dangers of battle, he also takes damage up to a number of d6s equal to the threat value, depending on his roll:

The hero’s modifier is based on the form of attack they are using. For example, a barbarian fighting with a greataxe would use his normal to-hit bonus with the axe when making his roll. Normal modifiers apply, but only if they would affect the majority of the attacks during the battle round. For instance, a bard using his action to sing for the round would grant morale bonuses to hit for allies on his team, and a barbarian affected by bull’s strength would use his improved strength score as long as at least 5 minutes were remaining on the spell’s duration, but activating his rage ability would not be beneficial since it only lasts for a few combat rounds. Instead, heroes can make use of their limited-term abilities such as rage, true strike, smite evil and action points during deadly combats (see “Resolve Deadly Combats” below).

Using magic: A hero may opt to use magic as his attack form for a round. To do so, he expends any number of spells (or spell-like abilities) with total levels up to his character level. It is assumed that the hero is casting spells or otherwise channeling magic in the most advantageous way over the course of the round. No hero contribution roll need be made, and the hero takes a fixed 50% damage.

Teaming: For teaming heroes, they check against the Flow of Battle table only once for the team. Each hero on the team makes a hero contribution roll, taking damage individually as indicated on the table above. For the purposes of the battle roll bonus, however, the team takes the highest result, adding a +2 bonus per team member beyond the first, to represent the assistance from allies. The total result is then compared on the chart above. Hence, it is easier for a team to achieve a higher DC, but the heroes might still have reached a greater total battle roll bonus fighting separately, depending on the situation.

Tactical maneuvering: If the general chooses to spend his attack action this round on tactics rather than fighting, he uses his Knowledge (tactics) skill for his heroic contribution roll. However, a general leading in this way draws attention to himself, and thus always takes 100% damage for that battle round.

Stealth: Stealth must be undertaken as a team—i.e., if anyone on the team wishes to be stealthy, everyone must attempt to be stealthy. Each person rolls a Stealth check and compares the result on the heroic contribution table. Everyone on the team must beat the DC… **TODO**

Terrain: Different kinds of terrain contribute to the battle roll in different ways, as determined by the GM. For example:

Artillery, air support or other offensive advantage:

Other modifiers (GM discretion):

6) Resolve Deadly Combats

A deadly combat is a break in the normal flow of battle where heroes briefly engage one another. Each deadly combat that has been incurred (see “Decide Heroic Actions” above) lasts up to ten rounds, and involves a conflict between the heroic team that rolled it, and the appropriate foes as determined by the GM. It is resolved as a normal d20 combat would be.

As a rule of thumb, to decide which foes a team of heroes encounters, first note the enemy units being targeted. From those units only, make a list of affiliated enemy hero teams. These teams are encountered from lowest CR to highest CR, but with enemy generals encountered last. The GM has the final say in which foes a team of heroes will encounter, and may adjust the order based on circumstance.

Note that it is possible for a team to be involved in more than one deadly combat in the same battle round. In this case, resolve the fights sequentially in an order determined by the GM.

Unconsciousness, Dying and Death: If a hero drops to 0 HP or below, he suffers from unconsciousness, dying and death as normal. A fallen hero retains his affiliation, and can be healed or resurrected as normal by allies with the same affiliation during subsequent utility phases (see “Perform Heroic Utility Actions” above). If a hero falls unconscious, his unit takes a -2 morale penalty that round (see “Make Morale Check” below. For every full round a character is unconscious, he takes an additional 1 point of damage per token targeting his affiliated unit as the battle rages around him.

7) Make Battle Rolls

Each unit rolls a d20, adding their appropriate modifiers, against DC 10 - token advantage. Success causes a targeted enemy unit to lose a token. For every 5 over the DC, a targeted enemy unit loses an additional token. In the case of multiple targeted enemy units, the fraction of tokens each enemy unit loses must match the attacking unit’s token allocation as closely as possible.

For example, suppose a robot unit with 17 tokens has allocated 5 tokens versus a unit of pirates, 3 tokens versus a unit of ninjas, and 9 tokens versus a unit of knights. Further suppose that the robot unit exceeds its battle roll DC by 17, thus reducing the targeted enemy units by 4 tokens total. The enemies lose tokens as follows:

In the case of any rounding ties, the attacking unit’s general chooses how the ties are broken.

8) Make Morale Check

Each general makes a Will save (using his own Will save modifier), DC 20, each round that his unit loses a token, with the following modifiers:

If the general fails the save, the army loses one token to desertion for every two points below the target DC (e.g.: a general who nets an 11 loses 2 tokens).

A final battle roll determines how many troops are defeated during the retreat. Apply the amount the general failed to the final battle roll to represent a “morale penalty” for the retreat. (E.g., if the leader fails badly, then this penalty could result in devastating losses during the retreat—i.e., a rout).

If a general is removed from the battle for any reason, the base Will save bonus for the morale check becomes +0. In this situation, another affiliated hero can take over as general at the beginning of the next battle round.


After the battle is over, some fraction of the casualties are merely wounded rather than dead. Some enemy soldiers may be captured, killed or exiled by the winning side afterward. The exact circumstances depend on the situation; it is the GM’s role to describe what happens.

Notes on wounds/vitality and vitality-based casting: