On Wandering Monsters and Random Encounters

A-Z 2015 "O"While working with the Pathfinder Roleplaying Game Reference Document (PRD) monster information I’ve noticed that there are very few wandering monster or random encounter tables. There used to be pages of them in each of the monster manuals of previous editions (at least, up to 3.5; I can’t comment on 4e).

So I went looking through some of the Adventure Path modules and found — or rather, didn’t find — much at all about random encounters. Again, back in the day you could pretty reliably count on finding at least one wandering monster table per level or region of an adventure, and now I don’t see them.

This makes me sad, a little. I play mostly old school games and find during play that the random encounters bring out things that might otherwise have not been seen. I think there is something gained by unexpected events in a scenario, even when the scenario itself is well-mapped.

If you’re familiar with my scenario design process, I develop an entity map, a graph showing the major entities (locations, characters, events, etc., as needed) in the scenario and how they are related to each other. This makes it quite easy to see and understand the scenario and how the pieces fit together. It works. Left at that, though, it comes to feel like everything is related to the scenario.

Strangely enough, this high cohesion can in fact reduce engagement in the setting because it is outside the scenario and thus not important. It becomes easy to forget that there is more to the world than just the quest the PCs are following.

Random encounters, random events, wandering monsters, they all can serve to remind the players that there is more going on. Their intrusion into the scenario or question can actually increase engagement because it becomes more evident that there are other things to explore. There may be other avenues to pursue goals, perhaps allies to be gained, or previously undiscovered threats to defeat.

Types of Random Encounters

Random encounters are often set up as just that. Throw a few monsters together, give them some hit points and loot, and drop them on the PCs when the dice say to.

This is a wasted opportunity.

I split random encounters into three broad classes: local notables, notable passersby, and local flavor, for lack of better names. I usually try to have about one third of the random encounters from each class.

Local Notables

These are encounters with creatures or situations relevant to the current scenario. The PCs might run into some patrolling guards (or wandering inhabitants), or a named NPC, or stumble on something one of the locals is looking for (“What has it got in its pocketses?”). This can cause a sudden shift in plans, potentially because the PCs have to quickly silence some guards, alarms are raised, a peaceful conversation happens that reveals some information.

Notable Passersby

Unless a scenario is in a tightly controlled area such as a dungeon (but not so much a megadungeon), it can be easy to have outside influences intrude. In a city scenario you could potentially interact with almost anyone: a pickpocket who lifts your purse, a drunken noble who is about to be mugged and could use some help, a traveler with news from abroad. A smaller town or village is likely more insular, but still you can have travelers and unexpected events.

These can all be opportunities to introduce information, hooks to other adventures, and (failing all else) experience points and loot.

Local Flavor

These random encounters and events provide an opportunity to make more evident the tone and nature of the scenario. The PCs might encounter local, unimportant monsters, or stumble on a natural feature of note, or find ‘dressing’ that helps make the place more memorable.

Designing an Encounter Table

To this day I still find the AD&D 2e encounter table design practices to be quite good.

Make a list of potential encounters and events, grouped loosely by how common you want them to be (common, uncommon, rare, very rare).

If you prepare your scenario to focus on ‘level-appropriate’ encounters you might plan to have APL (Average Party Level) encounters ‘common’, APL+1 and APL-1 ‘uncommon’, APL+2 and APL-2 ‘rare’, and APL+3 and APL-3 ‘very rare’. In class dungeon terms these might point to encounters from higher or lower levels.

Prepare a table with 19 entries, numbered 2..20. When an encounter is called for, roll d12+d8. This provides a range of frequencies from 1/96 chance of being rolled (2 and 20, each) to 8/96 (9 through 13).

Roll Frequency Frequency Description
2 1/96 Very rare
3 2/96 Very rare
4 3/96 Very rare or rare
5 4/96 Rare
6 5/96 Rare
7 6/96 Uncommon
8 7/96 Uncommon
9 8/96 Common
10 8/96 Common
11 8/96 Common
12 8/96 Common
13 8/96 Common
14 7/96 Uncommon
15 6/96 Uncommon
16 5/96 Rare
17 4/96 Rare
18 3/96 Very rare or rare
19 2/96 Very rare
20 1/96 Very rare

Assign the potential encounters or events to the table above so they align with your desired frequency. That is, place common encounters or events on the rows marked 9..13, rare ones on rows marked 4..6 or 16..18, depending what else you have present. I might have another column with notes about the encounter, such as (for local notables) their ‘normal home base’ (that’s where you might find the NPC’s stat block, after all, and if you kill him here you won’t find him there later), or how many goblins are actually present to be encountered (again, if you kill them all there will be none left for later).

Then, when the dice indicate a random encounter, roll d12+d8 on the table and you identify your encounter.

There are nine entries that are common or uncommon, accounting for 66/96 (slightly more than 2/3) of the entire table. I would try to assign two or three encounters or events of each type above to these entries. In places where access is constrained I might reduce the notable passersby. In cosmopolitan places I might increase them. The rare and very rare encounter entries are good places for weird or unlikely events, ideally ones that are not important to the advancement of the story.


I like to have multiple columns of potential encounters or events. There may be something I want to have likely to happen, but only once. In this case I might populate the first column of a ‘common’ row with that event or encounter and mark it ‘once only’, with a different encounter (or none at all) in the next column in case this row gets rolled again.

This can also serve as an escalation mechanism. The first time you run into goblin guards, if you don’t successfully evade them (or talk your way past, or pay them off) it might be a patrol of d4+1 goblins. On a subsequent encounter it might become 2d4+1 (with one being a sergeant) because the place is becoming more alert and patrols are going out in force. There might be an ‘alertness level’ that could move you from one column to the next even if you haven’t encountered the row before (i.e. if an alarm is raised then all patrols are doubled — next column over for ‘goblin encounters’ automatically).

Closing Comments

There was a time when I found random encounters arbitrary and time-consuming, and they could interfere with the expected activities and events.

I have since come to the conclusion that this is actually a useful feature. They provide me a way to introduce hooks and information about things that are outside the scope of the current scenario, to provide flavor to reinforce the tone of the scenario, and provide opportunities to do things that will change how the scenario plays out.


  1. I love the idea of wandering monsters linking into other adventures. It requires a bit of world building on the DM’s part, but it is very rewarding when done. Most of my encounters tend to be monsterless or use mundane creatures such as animals and humans as I save the monsters for special encounters. They also have potential for heroes to use skills other than combat skills. Here are some encounter tables I made http://www.arion-games.com/bb/viewtopic.php?f=13&t=789

    • It does take some more preparation, but even then it isn’t necessarily very much.

      When I drafted the Donnerkonig Heirs campaign[1] I identified 14 potential scenarios or adventure sites that could be involved. Only five are critical (Keys of Heraka-at, where it all starts, and the four where the PCs can recover important artifacts that will be needed later.

      In setting up a random encounter table for this adventure I have 19 slots available. Given roughly one-third for each group I have about six each of local notables, six local flavor, and six notable passersby. I see from the image below that I have five immediate neighboring adventures. I could have a passerby from each of the Shrouded Fen, the Sea-Swept Vault, the Spire of the Bronze Sorceress, the Horned Abbot of the Grey Canyon, and the Grotto of Aeshtua, Serpent of the Water. I might at this point decide that the Grotto and the Sea-Swept Vault are good ‘next steps’ for the PCs and put their passersby in the more common slots, but I think instead I’ll put the passersby from the Shrouded Fen and the Spire of the Bronze Sorceress there. Sea-Swept Vault and Grotto are immediately connected, the Grotto ‘twice’, so they’ll be relatively easy to find. The other two can provide direction to places the PCs will need to go and thus can be more helpful. The PCs don’t need as much help getting to Grotto or Sea-Swept Vault, so they’ll get the next two most common slots. I don’t really want to encourage them to go after Horned Abbot of the Grey Canyon, so I’ll leave that to an even less-common slot. That accounts for five of the slots, I might split the remaining fourteen between ‘notable locals’ and ‘local flavor’.

      From here all I really need is a loose description of the target adventure and its location. I would normally have an abstract of each adventure anyway, so identifying some specific creatures or events to use as ‘notable passersby’ doesn’t cost me much.

      [1] I define ‘campaign’ as a story arc expected to last 3-5 character levels. Much below that seems episodic to me, even if it covers a ‘complete adventure’, while more than that can feel unfocused and potentially lack conclusion or structure. I know that many people consider ‘campaign’ and ‘setting’ largely synonymous, but I prefer to think of the setting as a container for multiple campaigns.

      Adventure Map for Donnerkonig Heirs campaign

  2. Pingback: Z-A Challenge 2015 Index | In My Campaign - Thoughts on RPG design and play

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