Improved Mass Combat Rules (Part 1: Introduction) | Optional Rules for Dungeons & Dragons Fifth Edition

Tonight, I tested out mass combat rules for Fifth Edition Dungeons & Dragons of my own design. And I must say, they played pretty well. They allowed my guys to run a battle where their side had nearly 500 fighters under their command versus an army of roughly 1,000.

Wizards of the Coast already had a few rules come out a while back, but they weren’t so hot in my opinion.

When creating some mass combat rules for Fifth Edition, I made some quick adjustments based on swarm rules plus a method of “shrinking” stats to make it easier to track. Plus, I borrowed some mechanics from some wargames I’ve played over the years.

Here are the basics of how it all worked:

1. Units consist of 8 creatures of the same type. A creature essentially picks up a “unit” template.
2. The unit’s adjusted stats are as follows:
   • The unit is one size larger than its base creature. For example, a unit of knights becomes a Large unit of Medium humanoids (human), any lawful alignment. And a unit of ogres becomes a Huge unit of Large giants, chaotic evil.
   • The unit’s AC is the same as the base creature. If the unit has any effects that boost its AC (such as Parry), it automatically gets the boost.
   • The unit gains “unit hit points” which equal 1 hit point per every 5 average hit points the base unit has (rounded down). For example, a goblin unit would have 1 unit hit point, and a hobgoblin unit would have 2 unit hit points.
   • The unit’s speed is the same as the base creature’s.
   • The unit’s ability scores are the same as the base creature’s.
   • The unit gains a morale bonus. A unit’s morale bonus is equal to its unit hit points plus its Wisdom modifier.
   • The unit’s skills and saving throw bonuses remain the same. However, a unit rolls its saving throws and skills as one.
   • The unit maintains any vulnerabilities, immunities, and resistances that the base creature has.
   • The unit’s senses stay the same.
   • The unit’s languages stay the same.
   • Calculate the unit’s defensive challenge rating by multiplying the base creature’s hit points and its damage output per round by 8. For example, a knight’s hit points would be 416 and its damage per round would be 160 with its greatsword. That is CR 20.
   • If the unit has any special traits, these may affect the unit’s abilities. Details to come later.
   • If a unit’s base creature has multiattack, the unit may make more than one attack on its turn.
   • The units’ attack bonus stays the same as the basic units.
   • The unit’s attack is as follows:
     • Melee attacks count as an area of effect attack that affects a 10-foot cube (if a Large unit) directly in front of the unit. The attacking unit makes an attack roll against the unit or an individual creature within the cube. If targeting a unit, on a successful hit, the defending unit takes damage equal to the attacker’s damage score. On a miss, the defending unit takes damage equal to half the attacker’s damage score. If targeting an individual creature, on a hit, an individual creature takes damage equal to 40 times the unit’s damage score. And on a miss, the creature takes damage equal to 20 times the unit’s damage score. If an attack against another unit is made with disadvantage, the defending unit takes damage equal to half the attacking unit’s damage score on a hit and no damage on a miss. And if an attack against an individual creature is made at disadvantage, the creature takes damage equal to 20 times the unit’s damage score on a hit, and no damage on a miss.
     • Ranged attacks are made with the same range as the base creature’s range, however, the attack affects a 10-foot cube (if a Large unit) instead of just one target. If attacking a unit, the attacking unit makes an attack roll against the defending unit’s AC. On a successful hit, the defending unit takes damage equal to the attacker’s damage score. On a miss, the defending unit takes damage equal to half the attacker’s damage score. If targeting one or more individual creatures, each creature in the area must succeed on a Dexterity saving with a DC equal to 8 + the attacking unit’s attack bonus, taking 40 times the attacker’s damage score on a failed save, or 20 times the attacker’s damage score on a successful one. If the attacking unit has disadvantage on its attack roll against another unit, the defending unit takes damage equal to half the attacking unit’s damage score on a hit, and no damage on a miss. If the attack unit has disadvantage on its attack roll against one or more individual creatures, the individual creatures make their saving throws with advantage. On a failed saving throw, a creature takes damage equal to 20 times the attacking unit’s damage score.
     • A unit’s damage score is equal to the average damage of its attack divided by 5 (minimum of one). For example, if an archer would deal an average of 1d6 + 3 damage with its arrows, the unit’s damage score is 1.
   • If the base creature has Legendary actions, the unit loses these.
3. On a character’s turn, they can take their normal actions, or they can take the Command action. A character can Command a number of units within 30 feet of it that can hear or see it equal to their Charisma modifier (minimum of one). In addition, a character can Command any unit that they are a part of.
   • The character tells the units they command where to move and what action to take. Regardless of when the unit last took its turn, the unit moves in the same initiative order as the character.
   • A unit can take the Attack, Cast a Spell (if casters), Dash, Dodge, or Ready actions.
   • A character can also give a unit instructions to follow on its turn and subsequent turns (such as “go over there” or “move and attack that unit”). The unit will then follow those instructions to the best of its ability. A unit with instructions moves and takes actions at the start of the cleanup phase.
4. After a unit is activated, the character’s player marks the unit with an activation token. Any units that are following instructions have an instruction token placed on top of it.
5. A character’s statistics change while in mass combat as follows:
   • Any attack that a character or individual creature makes that normally only targets one creature has no effect on a unit. A character can only target units with spells attacks that have an area of effect that covers the entire unit.
   • When a character joints a unit, the unit’s unit hit points, AC, morale, attack bonus, and damage increase by the character’s Charisma modifier.
   • When a character is a part of a unit, they cannot be targeted by attacks.
   • A character can perform a Challenge action. The character targets one unit within 5 feet of it. The character then rolls a Charisma (Intimidation) check contested by the unit leader’s Wisdom (Insight) check. If the character is successful, it may enter the target unit. While within the target unit, the character cannot be targeted by the unit’s attacks and the unit cannot move or take actions on its turn. In addition, the character can fight the unit’s leader one on one (using normal combat rules). If the character defeats the unit’s leader, the unit is automatically broken and retreats.
6. A morale saving throw is made whenever a unit comes under duress. In addition to its own morale bonus, a unit can add the Charisma modifier of one character or leader within 30 feet of it that it can see.
   • When a unit takes damage equal to half or less of its total unit hit points, it must make a morale saving throw. The unit rolls a d20 and adds its morale bonus. If the die result is 9 or less, the unit breaks and retreats to the nearest edge of the battlefield. If the die result is a 10 or higher, the unit is fortified and it cannot be broken for the remainder of the combat.
   • A unit must make a morale saving throw whenever it is Commanded to move within 5 feet of a unit or creature that is one or more size categories larger than it. On a failed saving throw, the unit does not charge.
   • If an individual creature or unit is one or more size categories larger than a unit it is attacking, the target unit must make a morale saving throw. If the target unit fails its saving throw, it breaks and retreats to the nearest edge of the battlefield.
   • A character or leader can rally a broken unit within 30 feet of it. The broken unit makes morale save and adds the character or leader’s Charisma bonus to the check.

A few other rules I added as we played:

• The act of mounting horses took up half a unit’s movement. Once mounted, the unit’s unit hit points increased by the horse’s (so 3 in most cases) and the unit’s speed matched the horses. Additionally, the unit’s size went up one size category (since horses are Large).
• Certain siege equipment, such as trebuchets and ballistas, automatically count as doing area of effect attacks.

And these were pretty much the basics of how it worked. It watered down the rules and statistics a little but made combat move pretty smoothly.

Thanks for reading!

Of course, I’ve added in a few additional rules after the fact (after playtesting), but based on what I know of the game and how our combat played, I think a lot of this makes sense.

I’ll be sure to continue fleshing out these rules in the future.

Thanks for reading!