13th Sage: PC-Focused Mass Combat Rules

13th Age - Death Of ThroneWhen you’re adventuring in the 13th Age, things sometimes get…out of hand. Maybe you stumbled into (or instigated) a violent uprising against the local authorities. Or maybe, thanks to that ritual you performed at the heart of a living dungeon, you accidentally brought about the end of the age — and massive armies dedicated to opposing icons now fight to determine who will rule the age to come.

Mechanics for mass battles in an RPG should help determine:

  1. The outcome of the major conflict
  2. How the events in that conflict affect the PCs

In the megadungeon adventure Eyes of the Stone Thief, the PCs might become involved in mass combat. For that particular scenario, the focus is exclusively on the PCs and how the chaos around them helps or hinders their fight against their enemies. So the mass combat mechanics Gareth devised for that scene are more like terrain effects than they are rules for running a wargame-within-a-game (such as the free mass combat rules recently provided for Dungeons & Dragons).

Gareth and Rob Heinsoo are collaborating on full rules for 13th Age mass combat, to be published in 13th Age Monthly. In the meantime, here are the PC-focused mass combat rules from Eyes of the Stone Thief:

PC-Focused Mass Combat Rules for 13th Age

These mechanics are useful when you want to run mass combat like a battle in a Shakespeare play: the focus is on the fight between the PCs and their enemies. The larger conflict takes place offstage, and is only relevant to the extent that it helps or hinders the characters.

Don’t bother with tracking the hit points of the various combatants, except the ones the PCs are actually fighting. Just describe the carnage as the various sides battle it out, while the PCs take on the toughest part of the enemy forces.

Allied and enemy forces are represented with d6s. At the start of battle, give each side a number of d6s from one to three depending on the strength of each fighting force (call them “Ally Dice” and “Enemy Dice”). A gaggle of ill-equipped peasants might warrant one die; a small to medium-size force of trained fighters give two dice, and a huge force of well-motivated soldiers are worth three dice.

NOTE: In Eyes of the Stone Thief, the number of Enemy Dice is determined by a mechanic called the Alert Level which tracks how aware the monsters are of the threat posed by the dungeon-crawling PCs. It’s quite cool, but it’s a mechanic specific to situations where the PCs are lurking about in a dungeon, so we’re not going to worry about Alert Level here.

Each round, roll the dice for each side.

For every 6 in the result, that side does something that affects the PCs’ fight. If the 6 is a result of the Ally Dice roll, it’s a help; if it’s a result of the Enemy Dice roll, it’s a hindrance.

For every result of 5, that side does something that affects the PCs’ fight, but at a negative cost to themselves.

Possible effects include:

Help Hindrances
An ally chucks a spear into an enemy that one of the PCs is engaged with. The enemy takes 3d8 damage. An enemy takes a pot-shot at a PC—it’s a +10 attack vs. AC for 4d8 damage.
The cheering of your allies invigorates a PC; that PC can heal using a recovery. Add a bunch of enemy mooks to the fight as reinforcements.
The enemy forces fall back; increase the escalation die by 1. The enemy forces hold firm; the escalation die doesn’t increase this round.
Your allies push forward; remove one Enemy Dice. The enemy forces push forward; remove one Ally Dice.


Let cool PC stunts and killing big foes remove Enemy Dice. Removing all Enemy or Ally Dice doesn’t mean there aren’t any enemies or allies left, just that they’re not going to affect the PCs’ fight for the rest of the battle.

Example 1: The PCs have freed some gladiators who were enslaved by orcs, and are trying to fight their way out. The GM gives the players two Ally Dice to roll, and puts down two Enemy Dice on her side of the table. She picks different colored dice, because one is for the orcs and the others are for monsters that broke out of the gladiatorial arena.

The battle starts, and all the dice get rolled. On round 2, one of the Ally Dice comes up with a 6. The GM asks the players to describe how one of their allies helps out, and a player decides that one of the gladiators — infamous for fighting dirty — jumps into the fray and gouges out the eyes of an orc warrior. That orc is now hampered.

Later that round, a PC pulls off a difficult stunt that kills every mook in the PCs’ battle with a single hit. The GM removes an Enemy Die as some of the smarter orcs in the larger battle witness this act, and decide to quietly flee while they still can.

Example 2: While the armies of the Dwarf King clash with an invading army of dark elves, the PCs face off against the dark elf general and her personal guard of elite sorcerer-knights. Because both sides have shown up in full strength and ready for war, the GM gives the players three Ally Dice to roll and puts down three Enemy Dice on her side of the table. 

On round 4, one of the Ally Dice comes up with a 5, and two of of the Enemy Dice come up with 6s. The GM asks the players to describe how one of their allies helps out in a way that costs them somehow. A player decides that one of the Dwarf King’s paladin commanders stops to heal a badly-wounded PC, but is killed doing so. Suddenly a cheer goes up from the dark elves as a powerful demon joins the battle, incinerating scores of dwarves with a wave of its hand. This, on top of the loss of the paladin, is too much for the dwarves and they fall back. The GM reduces the escalation die by 1 and the players can only roll 2 Ally Dice next round.

13th Age answers the question, “What if Rob Heinsoo and Jonathan Tweet, lead designers of the 3rd and 4th editions of the World’s Oldest RPG, had free rein to make the d20-rolling game they most wanted to play?” Create truly unique characters with rich backgrounds, prepare adventures in minutes, easily build your own custom monsters, and enjoy fast, freewheeling battles full of unexpected twists. Purchase 13th Age in print and PDF at the Pelgrane Shop.

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