I plan to send my players into a town of about 600 inhabitants. Overnight the town will be infested with zombies, with about 400 inhabitants turned. When my players awake, they will need to get out of town, since killing every zombie won't make much sense.

Now consider this situation: The players want to exit by boat on the river, but the docks are full of zombies, say about 100. The players will have to fight their way through until they reach a boat. Since moving each one of the 100 opponents would be time consuming (and stupid), I was thinking about running chunks of zombies as a kind of swarm, but have no idea, which stats to give this swarm.

The whole battle should take place on a large battlemap (it will be online, so size of the map is not an issue).

How can this encounter be played, so it has "realistic" probabilities, and is still fun to play?

  • 3
    \$\begingroup\$ I wouldn't put it past a D&D party to try and kill all ~400 zombies. And possibly succeed. \$\endgroup\$
    – aslum
    Commented Feb 25, 2015 at 14:31
  • 3
    \$\begingroup\$ I'd also be prepared for the PCs to try to save important (read: "named") NPCs. Be ready to decide if the PCs' friends are already gone, of if the PCs can rescue some/all from the horde. \$\endgroup\$
    – minnmass
    Commented Feb 25, 2015 at 17:45

4 Answers 4


According to d20pfsrd.com, third party publisher Frog God Games' Megadungeon Rappan Athuk features one or more Zombie Hordes.

A horde is a pseudo-swarm consisting of medium-sized creatures, since regular swarms are limited to Tiny or smaller creatures. It is Colossal-sized and deals damage to everything sharing its space, just as a swarm does.

The rules for hordes are described in the Horde Traits in the creature description.

Horde Traits (Ex)

Hordes are not so called because of the size of the group but rather the size of the creatures that compose the horde. Unlike normal swarms, hordes are composed of Medium creatures which are usually a normal version of a creature but otherwise behave in a swarm-like manner. There are usually around 50 creatures in a horde. The net effect is that they take only half damage from piercing weapons but take normal damage from other weapons. In addition when the swarm is reduced to 0 hit points or lower and breaks up, unless the damage was dealt by area-affecting attacks, then 2d6 surviving members of the horde continue their attack, though now only as individual creatures. Otherwise, a horde conforms to all of the other swarm traits.

One particular point of interest is that a horde can split up into a number of individual creatures when defeated, unless it was nuked using area effects.

Another interesting feature is the modified Rend ability, that triggers when the horde deals 25 or more damage to a creature, which happens 20% of the time. AnyDice predicts an 22.52±7.24 points of damage on average.

At CR 14, it looks rather weak to me. The damage output is low, AC might as well be 0 at this level and a mere 110 hp. It's saves are low as well. The only high defense it has is HD, but that one isn't targeted very often.

A single fighter 8 with Str 22 and a +2 greatsword will deal 2*27 damage with power attack, potentially killing in two rounds what according to the d20 Encounter Calculator should be "Unbeatable".

For comparison, other CR 14 creatures are the Nalfeshnee Demon, or and Adult Red Dragon.


Don't use combat mechanics

AngryGM writes a piece here about D&D combat (which can be applied to any system, really; they all have such heavy combat focus 'by the book'). His posts on encounters and combat are solid reads, and the 'Zombie Horde' is actually a specific encounter that he uses as an example in the linked post.

His suggestion: don't use combat rules. Essentially, don't shoe horn an exciting encounter like this into the limited framework of battle mechanics.

You can still run a sort of 'initiative' order - take actions from each PC and then explain the results, then narrate how the horde behaves and reacts. This then gives you a 'time unit' to pace things like damage, risk of being turned, position of the 'swarm', etc.

This should also encourage your players to think outside the combat 'box', choosing actions to help disperse the horde that might not have occurred otherwise.

  • \$\begingroup\$ Agreed. One of the more obscure RPGs I've played incorporated a system for handling dull or grinding encounters if you didn't want to play them out; it involved basically rolling a few percentiles and doing some multiplication to calculate how much damage everybody took and how much total XP was gained. Encounters that aren't likely to have significant consequences shouldn't need to be run in full. \$\endgroup\$ Commented Feb 26, 2015 at 4:23

There is a 3.5e book called "Heroes of Battle" that has rules for massive battles; it includes rules for converting large groups of creatures into swarms. Probably even contains "Zombie Swarm" as an example, although I'm not sure.

While not designed for Pathfinder (being much older) it should be easy to adapt, you can probably just copy the monsters and templates directly into Pathfinder for the most part.

At the very least, it's loaded with great information on how to run battles that involve hundreds of creatures while keeping them doable, so it'll be a good read for such an encounter.


In A red & pleasant land Zak S. introduces a system for parties participating, but not playing a major role, in large battles, that could probably also be used here. The idea is to have them fight a number of smaller encounters. The difficulty of the encounters is determined by the time the previous encounter took.

In short:

  1. Create a list of possible encounters order them according to difficulty (1=easiest).
  2. The number of rounds they take for the first encounter is the number of encounters they will have to face before reaching their goal.
  3. After every encounter roll a die add the number of round the encounter took. That will be the next encounter from the list.

Even not using this specific system you could of course always use the more general idea of splitting the encounter into several smaller ones.


You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .