Random Encounter Tables: A Guide


#1

Hail, Game Masters!

In this post I’m going to give you a complete guide to using random encounter tables (RETs) in your games. This will cover everything from what an “encounter” is, how to construct random encounter tables, and the myriad of ways to use them to enhance your game. So grab your favorite drink and sit for a while.

What is an Encounter?

An Encounter should be defined as, “Anything the players encounter”. Simple, right? But deceptively so! Random encounters need not always be monsters. Encountering a terrible storm, a raging wildfire, a destroyed bridge, an NPC in need, or a “moral dilemma” are all encounters that can exist in your tables. The key here is to free yourself from the misconception that every encounter has to be combat. With that said, let’s talk about what a random encounter table is, what it does, and how to make one.

Random Encounter Tables: An Introduction

Sometimes called wandering monster tables, random encounter tables are lists of numbered experiences that you design ahead of the game, and then roll on to generate encounters for your players to solve. They can and should include more than just things that want to eat your players (but some of those are great too). Indeed, a wandering monster table is only one kind of random encounter table. There are many others. RETs perform several functions: (1) they allow you to fill wilderness and dungeon exploration with interesting moments, (2) they help to simulate a living world without you having to do an immense amount of pre-session prep (aka, regenerative content), (3) they absolve you of the responsibility of making “balanced” wilderness encounters, (4) they allow you to organically and effortlessly create side plots as you play, and (5) they are the easiest and (in my opinion) best solution to the 5-minute adventuring day. Oh, and (6) they’re damned fun to interpret as the Game Master.

So, that’s what RETs are and the function they fulfill. How do we make them?

Designing Random Encounter Tables

First, you should decide what kind of RET you want to make. Is it a list of monsters your players could encounter? What about changes in the weather? Natural hazards like brush fires and steep cliffs that PCs need to navigate? A compound table with multiple kinds of encounters? Once you’re in the right headspace, they are easy to create. Here are the quick and dirty guidelines to making RETs that pay dividends dozens of sessions down the line:

  • Imagine the space your PCs are exploring. Is it a heavily forested hillside, a frozen tundra, the depths of the emerald sea, or a kobold lair? Pick things that players would reasonably expect to encounter in that type of area. For the sake of this example, we’ll take a heavily forested hillside.
  • Decide on the length of your table, and try to keep it set to a die-parameter for easy rolling (4, 6, 8, 10, 12, 20, 100, etc.). Twenty is a great number, but 100 is often more useful in huge sections of the world such as an entire hillside.
    • If you choose a higher number of entries, such as 20 or 100, remember that you don’t have to have that many entries! If you choose to use a d20 to roll, you could have the most likely encounters (say, orcs and goblins) occupy 50% of the table! Then the remaining 50% could be used on less common monsters, with the “19” and “20” rolls being the rarest or most dangerous encounters. The same goes for d100 tables. For d100 tables, it’s not unusual to have the first 70% of the table be common encounters, 20% be uncommon, 7% be rare, and the last 3% be very rare encounters.
  • Start filling it in! Start with the most obvious and interesting ones. For a heavily forested hillside, we can think of several things: orcs, goblins, hobgoblins, gnolls, bandits, cultists wolves, bears, stirges, traveling humanoid NPCs (humans, elves, dwarves, etc.), NPC adventuring parties, giant versions of natural animals (giant snakes or spiders) and so on. Add some odd balls like oozes, slimes, common undead (skeletons, zombies, ghouls), centaur, ettercaps, and trolls. Consider some more dangerous creatures at the end of your table, such as wraiths, ogres, or gargoyles.
    • Don’t forget to assign a “number appearing”! Do you want them to meet 3d4 orcs, or 2d8? What about d4 wights, or only ever 1? This is entirely up to you.
    • Remember, keep these focused on things that are believable. Your players aren’t going to encounter half a dozen fire giants in the middle of the arctic (if they will, that should probably be part of your session notes and not randomly generated).
    • If your RET is not focused on creatures the players could meet, and instead on points of interest or challenges, do the same process as above. To continue, the players have to deal with: a wildfire, flooding, a terrible storm, blinding fog, a precarious vine bridge, a narrow rocky ascent, a pit trap with spikes, and so on.
    • Consider having some of your random encounters be good things. The players stumble upon an ancient druid stone that allows them a Full Rest, a cave that provides shelter from the storm, a ranger’s cache of supplies, and so on. There’s nothing wrong with a lucky roll.
  • Once you’ve filled in your table, let it breathe for a bit and come back to revise it in an hour or so. Ensure that the entries fit your themes, and that they sound fun to you.

Recap: Take some time to imagine the space the tables are designed for, decide on a length for the table, fill it in. Easy. Let’s talk about how to use them.

When to Roll on Random Encounter Tables

So you’ve got your slick new table that’s bursting at the seams with cool ideas. Now we’ve got to put it to work because remember, random encounter tables are designed to do a lot of lifting for you. First things first, when do you roll on the table? Many Game Masters use RETs during wilderness or dungeon exploration, and during camping. Here’s how it works: (1) Use a die to determine if there is a random encounter or not, (2) if there is, roll on your table. I use a d12, but you can use any die you like. For me, on a result of an 11 or 12, there is a random encounter. For wilderness exploration, I tend to roll this d12 during the Morning, Afternoon, and Evening (three times total) – and then during every watch the players set while they camp (usually two). You should adjust this Check Frequency to your liking. You can do it once per day and once per watch, or much more often. However – I do not recommend doing it more than three times per day, and two or three times per watch. Even then, that’s a lot and represents a very dangerous world that will seriously strain the resources your players have. Moving on.

You can also, at your choice, roll for random encounters prior to a session so that you can incorporate them into your notes if you want them to be a little more thoroughly baked. There’s nothing wrong with that.

Using Random Encounter Tables

One of the key aspects of RETs, and arguably the most misunderstood thing about them, is that NOT EVERY ENCOUNTER YOU ROLL IS A COMBAT ENCOUNTER. These tables give you a huge amount of creative mojo and you should use them to make your world come alive. Let’s address one of their criticisms: Random encounters, because they are random, just detract from the main story. The debate over whether or not you should even have a main story aside, this claim is only true if the tables are used poorly. Random encounters are just starting points. Yes, finding 3d12 undead in the middle of the town is… weird. Not unworkable, but not very slick. Let’s talk about how to properly use RETs.

Your players are in a tight mountain pass. The driving snow has made sight and hearing difficult. You roll a d12 to determine if there is an encounter on this leg of the journey. Having rolled an “11”, there is. You consult your RET and roll on it. Your die lands on “17”, indicating that the players encounter 2d6 cannibals. You roll 2d6, and get a total of 8 – they are going to encounter 8 cannibals.

That’s all the table tells you. You have to interpret the results. This is one of my favorite parts of GMing! You should immediately have tons of questions coming to mind. Why the hell are there cannibals out here? What equipment do they have? What are they doing? Where are they, exactly? Do they have a camp nearby? And so on. Here are a few ways you could interpret the results.

  • The 8 cannibals are waiting in ambush, for they know from experience this is the only pass through the mountain. Once the players are in range (roll for surprise, if that’s your thing!), they chuck spears from the cliffs above. The players are sitting ducks and it will be difficult to reach the cannibals.
  • The 8 cannibals are wounded from a battle with the yeti of zone 3 (which is part of your prewritten notes for the session), and only have half their normal hit points. They are hiding in a cave and obviously injured. The PCs discover them on accident while seeking shelter from the snow. The cannibals immediately draw up arms, but don’t outright attack – they’re just defending their own. What will the PCs do?
  • The 8 cannibals are fighting amongst themselves! The PCs hear their throaty yowls over the snow and, if they approach, will see one heck of a brawl. The PCs can choose to engage and sort it out (perhaps not realizing the cannibals are all basically mindless), or move on through. If they do nothing, you might decide that the noise from the cannibals fighting draws the yeti from zone 3 – but the yeti find the PCs first.
  • The 8 cannibals are heard chanting on the wind. The PCs find them ritually sacrificing their old chieftain, and if they disturb the ritual (failed stealth check), the cannibals fly into a rage and rush them – bone axes and diseased fingernails at the ready!
  • The 8 cannibals are actually Friendly to the players (make a reaction check if that’s your jam), and think they’re sent from a nearby duke to finally rid them of some disease. What happens if the players refuse? What if they agree?

As you can see, I’m just spitballing. But that took me longer to type than to imagine. And I didn’t even mention the terrain. How does example 3 change if the cannibals are fighting on the stone bridge forward – the ones the PCs have to cross to reach their destination, or turn around and lose three days of progress (risking more encounters)?

After The Encounter

So the encounter is over. The PCs murdered the cannibals, helped free them from their disease, or were caught up in the brawl. There might be some natural consequences of this. If the PCs were able to cure the cannibals of their disease (perhaps a Paladin used Lay on Hands), you now have a very thankful group of tribal warriors that are indebted to the PCs. If they killed all the cannibals, what happens when the PCs discover they had a handful of children hiding in the bushes nearby, now orphaned? How did I know there were children nearby? I made it up!

Beyond these natural consequences, you now have some big-picture questions. Had you not rolled “cannibals”, the PCs may never have discovered them. Indeed, the cannibals would not have existed . But now they do. Are there more? Where? What’s their home like? How many are there? What are they doing? Are they leaving the nearby town of Tirisbal alone, or are they sending raiding parties and harrowing the roads? Where are the answers to these questions? Just make it up. Enjoy the emergent process.

What happens if the PCs’ next random encounter is a bunch of zombies, and by chance, is in that same mountain pass? Heck – it sounds to me like a necromancer rolled through, found the dead cannibals, and reanimated them! Imagine your players’ reactions when you describe the cannibals they killed last week now shambling through the fog towards them. Gold, and it took zero pre-planning on your part. The table did the lifting. Now you’ve got more to work with. What reanimated the cannibals (a necromancer, and ancient magic far below in the caverns of carnage, or the shooting star)? Why is that thing, say a necromancer, here? Where is here? Will the necromancer eventually become a recurring villain that steals the show (and their souls)? Only you can decide that.

Or, you can just let a random encounter be a random encounter, and call it quits. Sometimes, the PCs just get attacked by hungry wolves. But why are the wolves so hungry? Where’s all the natural prey? Did something eat it? Maybe a manticore? The brain storm goes on and on…

One final tip: Random encounters are not constrained to the thing you wrote. What if those 8 cannibals are in a pitched battle against dark dwarves (which you decided on because you want to lay a clue about the incoming dark dwarf invasion from the underdark, which is in your notes)? The dwarves aren’t in the encounter table, but they don’t have to be. The RETs are tools, not masters.

GAME ON


#2

All good stuff. I only have a few things to note how I like to use random tables from time to time.

  1. During session prep. Use random tables to populate and generate the adventure, so you don’t have to take a time out during play to roll and figure out what is going on. You still get the randomness, and you still benefit from the creativity as a result of interpreting the results. Really cool situations that you might never have imagined can come out of this, and your players will think you are some kind of DM wizard.

  2. Have the players roll on the tables. Players always like to roll more dice. And letting them know it is THEIR roll that is determining what happens next really removes the DM vs Players paradigm. But make sure the players know the stakes. This is where the rangers can shine with their wilderness survival skills.

Example 1: “It is clear something is following you. Roll Survival/Nature/Whatever to see if you can throw it off your trail.” Then have them also roll on the table to determine what creature it is. If they succeed the survival roll, they have a chance to ignore/follow/ambush/stay put while the thing(s) move on. If they fail, they get caught by said thing(s)

Example 2: “While sleeping, Player A is on watch. Player A, roll to see if anything unusual happens on your watch…”

Example 3: “You come across a lair or den of sorts. Roll to determine what lives here…”

Example 3.5: “You come across a lair or den of sorts. It is clear from the tracks that everything from goblins to owlbears to trolls and more have been in the area. Roll to determine what is currently occupying it. You can add your Nature skill; the higher the roll the more benign the outcome…”

I like having the players roll, with at least some idea of what they are rolling for. It serves to peak their interest and get them invested in the outcome of the roll. If the DM is rolling dice, and the players have no idea what for, or what the possible outcomes are, then they cannot be invested as they have no agency. You can also use these “encounters” as an excuse to have little used skills shine. History, religion, survival, all that good stuff. And if the result is an encounter the players don’t want to engage, they will get creative and figure a way out. Bluffing, intimidating, running, hiding, all them goodies.

There is also an amazing little book called “The Perilous Wilds” (check it out on DriveThruRPG), that is a supplement for Dungeon World, but it works for everything. The entire thing is mostly focused around randomly generating encounters (from simple monster combats to entire sprawling dungeons) on the fly, with just a few dice rolls.


#3

Good post.

Die-parameters? I use composite dice for my own tables! Mwuahaha!

Also, cross-referencing tables usually makes for a more complete interpretation fun! Just a recommendation! :+1:


#4

@PrawnWonton Great input! (1) Yep, randomly generating the “meat” of adventures can be so fun. Imagine my surprise when I was running Desert of Desolation back in the day and found a huge amount of crocodiles… moments later, LIZARD PEOPLE ruled the deserts! (2) Yep, that’s a good pointer. I have had players roll the D12 and D100 sometimes, and they always feel the pressure.

You also give other great examples where random generators are very useful. What I find most interesting about them, in general, is I can run an adventure dozens of times from the same base components, and they will be measurably different experiences each and every time. That’s awesome.

And yes, Perilous Wilds is great! I don’t like all the material therein, but still a very handy book

@BlazingPolyhedron Composite dice ftw! But really, I usually stick to something I can roll with a single die. Feels heavier at the table for me (though that could be my tungsten dice…).

Yes, cross-referencing tables is the higher end operation in my opinion. I usually nest my tables within each other. For example, my big d100 random encounter table has entries for Roll on the Random Weather Table, Roll on the Random Terrain Table, Roll on the Random Wild Animal Table, Roll on the Random Situation Table, and so on. The Random Weather Table might, in turn, have an entry for Severe Weather, and Roll on the Random Monster Table. You can really get creative with RETs. Most importantly for me, my tables usually do about 80% of my inter-session prep for me once they are created. They are THE way to do proper hexcrawls/sandboxes.

Cheers!