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Just Roll With It: Creating Random Encounters
Wednesday , 07 December 2016 , 11 : 37 AM

Random encounters.  A lot has been said about this subject and a lot has been created to ease the burden of the time poor Games Master, but here is my attempt at handling one of the most fun parts of being a GM, and it can be used in digital or online play.

Getting from point A to point B can be a real pain in the ass, even in our mundane lives (thanks for getting my hopes up Star Trek).  There's the whole problem of time/space being in the way of where we are, and where we want to be.  In our chosen fantasy worlds, we're also subjected to nasty stuff occupying the same time/space that we're attempting to cross.  Goblin ambushes, orc ambushes, human ambushes…..you get the idea.  Creating interesting things to break up the journey is key to creating an immersive world for your characters to live in, and so we have random encounter tables.

Random encounter tables give us an element of randomness in our games that do a few cool things:

  • They give the GM an opportunity to tax the characters' resources
  • They add to the ongoing narrative.

Let's look at number 1.  Players have a certain amount of resources that they are able to use within a certain time period; this is true of the majority of RPG systems.  Whether it's HP, spells per day or rations, you want to keep pressure on your players and don't let them get complacent about when they'll have a chance to replenish their resources.  Random encounters add to this uncertainty and create an atmosphere of tension.  Also, there's the tasty, tasty XP and loot as a return for the players, which they'll appreciate all the more.

So that's the mechanical side of it: putting pressure on the characters' resources.

Number 2 is way more interesting (giggle).  Random encounters add to the ongoing narrative by introducing an element of randomness to the plot, allowing the DM to leverage the encounter into either new information for the existing narrative, or as a potential branch of a new narrative.  With one roll (more or less, but I'll get to that) you have either the opportunity for more exposition, or to introduce new weirdness, or both.  Let's take The Hobbit as an example.  The journey to Rivendell could have been handwaved and suddenly The Company is chatting to Elrond.  With the narrative being as it was, and assuming a GM who likes things neat and tidy, one might assume that the GM would stock the area with level appropriate creatures, so maybe a patrol of elves, or some racist humans or something.  Instead, the Company encounters a much more interesting threat, and the story is changed dramatically with the acquisition of the elven blades.  Players like stuff to happen.  They want exciting stuff to happen, and by using random encounter tables, and a bit of GM ingenuity we can give that to them, and then some.

As you can see, random encounters are fun and engage both the mechanics and the narrative, and by doing so engage the players.  I'm going to show you my super simple way of making a Random Encounter Table for improv DMing.  You're going to need a fist full of standard D&D dice, and your brown pants.

The first thing you need to do is work out if there even is an encounter.  To do this I roll 1d10.  On a 10+, the players have a random encounter. If you roll a 1, you will encounter terrain that may or may not be fun (keep reading, it will make sense).  You can add/subtract modifiers to increase the odds, maybe a +2 for night time, or maybe the road is super spooky.  That's up to you, Mr DM.  Don't worry about what it is, that's coming up. 

Next, we check for what kind of encounter we have.  Roll a d4.  On a 1, the encounter will be with hostile creatures, on a 2, they will be friendly.  Yes, this means the peaceful unicorn might want to murder you, and the hungry vampire just wants someone to talk to, but that's cool.  On a 3 or 4, the creature will just act like a normal creature of that type.

So we know who, and maybe why; next, we find out where.  Much like the previous roll, we're going to see if things are going to help or hinder us.  Roll a d6; on a 6, the place where the encounter takes place will be beneficial.  Maybe the players have the high ground, or maybe there's a fountain that heals Good Aligned creatures 1d4 hp per round.  Whatever it is, it's going to be there explicitly for the players.  On a 1, the terrain will actively hinder the players (but not the opponents).  Maybe it's a dank grotto with poisonous mushroom spores, or maybe it's a macabre body horror circus.  2-5 means that the terrain favours neither side, or it could actively work against both. Remember what I said above about rolling a 1 for an encounter?  That's where this comes in; sometimes it's cool just to find a cool place.

Awesome!  Cool!  You're so attractive!  I hear you say.  But what about the monsters?  What do I put there?  Well, this is your last roll.  Throw a d12.  Here's where it gets a little tricky, and you need a table.


2, 3, 4

5, 6, 7, 8

9, 10, 11







This should pose no challenge to the party in combat.

Encounter should be dangerous only if the characters mess up.

Standard encounter at the appropriate level.

The encounter has the potential to be deadly, but won't result in TPK.

I hope you bought those spare character sheets you printed.  Very possible TPK.

Alright!  Now you know where the encounter is happening, where it's happening and how difficult the players will find the encounter.  The question remains is who are the brave adventurers encountering.  It's the crux of this whole thing, the cornerstone of the mechanic.  The answer is; it depends.  I don't know, you're the DM you work it out.

Harsh, I know, but that's what it's all about.  What does your game need, what does it demand you to throw in the way of your players.  If the characters are in Mirkwood, there's going to be spiders.  If your players are in Alexandria, and the zombies have escaped The Quarry, there's going to be zombies, but maybe even some raiders (seriously, what the fuck The Walking Dead?).  If your characters are in a dungeon ruled over by a troll lord….well, you know what to do.  You know the place, level of difficulty, and the initial disposition of the encounter, the rest is just about using your imagination.

Using this in Roll20

This whole thing started as a request from a buddy to show him how to make this system work in Roll20 (which is super rad, by the way.  Check it out at http://www.roll20.net), so this is how to make it work.

The first thing we need to do is set up some tables.  We're going to need 4 of them.  The first one we will call them ENC, DIS, LOC and DIF

ENC will contain just 2 table items, but I like to flesh them out with many more variants.  Call one of the items Encounter, and the other one will be Nothing.  Set the weight of Nothing to be "9" and the weight of Encounter to "1".  I personally have 9 distinct items for nothing that say stuff like, "Huh, must have been the wind", "Your journey continues without incident" and so on.  The key here is the there is a 1/10 chance for an encounter to happen.

DIS shows the disposition of the encountered creatures.  We're going to make 3 Items here.  Friendly, Natural and Hostile.  Give Friendly and Hostile a weight of 1, and natural a weight of 2.  Again, you could make a whole heap of synonyms but this one stays hidden from the player, so it's kind of pointless.

LOC.  I think this is another one that you could potentially blow out with a whole heap of additional information, like what sort of location it is (maybe it's religious, or arcane, or of historical import), but for now, let's just set it up to have 3 items.  Hostile Terrain, Neutral terrain and Friendly terrain.  Set the weighting to 1 for hostile and friendly, and 4 for neutral.

The final table is DIF.  It will have 4 items; Inconsequential (weight 1), Easy (weight 3), Medium(weight 4), Hard (weight 3), Deadly (weight 1).

Now that you have your tables, you're going to set up your macro for your players to roll on.  My macro looks like this:

/em rolls to check for an encounter:

/r 1t[ENC]

/gmroll 1t[DIS]+1t[LOC]+1t[DIF]

The first line creates an emote marcro that says that an encounter roll has been made.  Flavour text.

The second line will tell the players if there's an encounter or not.  Writing this, I can see the potential to create an additional entry that gives a false negative to use for ambushes, but I'll leave that for another time.

The third line sends the results of the tables we made to the GM.  Only they know what's really happening and the amount of trouble the characters are in.

Here's what the output looks like, and what I might do:

DM Owlington (GM) rolls to check for an encounter:

DM Owlington (GM): 

rolling 1t[ENC]

(Your journey continues without incident.)


(To GM) rolling 1t[DIS]+1t[LOC]+1t[DIF]

(Friendly creatures)+(Hostile Location)+(Medium)


This one's easy.  As a gm, nothing has happened.  The coast is clear.

DM Owlington (GM) rolls to check for an encounter:

DM Owlington (GM): 

rolling 1t[ENC]



(To GM) rolling 1t[DIS]+1t[LOC]+1t[DIF]

(Neutral creatures)+(Hostile Location)+(Hard)


This is an encounter.  Now, the encounter is with Neutral creatures, and they're going to act as described.  Goblins, zombies, elves or gnomes; they'll act in accordance with your narrative.  Your campaigns evil Halfling necromancers will do evil necromancer things.


The location is described as hostile, so that's not good.  It will work against your players.  Maybe fighting an uphill battle, or maybe your players have stumbled on a nexus of negative energy the Halfling necromancers are using to power themselves up?


The difficulty will be hard.  Depending on the system what this means could change, but you should also look at the terrain roll.  In this case I would be adding a bunch of undead to the gnome encounter, and maybe nerf the characters healing ability

DM Owlington (GM) rolls to check for an encounter:

DM Owlington (GM): 

rolling 1t[ENC]



(To GM) rolling 1t[DIS]+1t[LOC]+1t[DIF]

(hostile creatures)+(Neutral location)+(Medium)



Another encounter, but let's change the system:


Zombie apocalypse.


In the narrative, zombies aren't the enemy, they're part of the landscape.  The real enemy is the other survivors, so that's who the players will be fighting.  They're also hostile, so we know that the other group will start the fight, potentially even trying to trick the players and sucker them.


The location is neutral, so it's not going to benefit either side.  This will take place in a sports stadium.  The bleachers are well protected, but the field is full of the restless dead.  This landscape is potentially dangerous to both sides.


It's medium difficulty, but because of the potential of the zombie pit to cause death to the players' characters, the group of hostile survivors will be a bit weaker to compensate.


So there it is.  This is how I do encounters.  I hope you find something useful in there that's going to help your game, or at least something that made you raise an eyebrow slightly and go say "hmmm, interesting".

Remember the golden rule: make awesome things.