01 February 2023

Creating Unlockable Encounter Tables

Springing from a nice layout on Developing A World Through Encounter Tables by Welcome to the Deathtrap on how they make encounter tables I wanted to walk through how I made mine for Southern Reaches.

Given the drop-in, player-guided nature of the game, it becomes more important to get a bunch of ideas down in an encounter table so when I come cold to some nook of the campaign later, it is all ready to go. For other campaigns the players are on a more steady trajectory but for more open world, they could go anywhere. I decided to dust-off the unlockable 'hidden depths' style of encounter tables so I could get everything down in one place.

Rather than going with all the options which is good for creeping conditions, a chaos scale or the like, I just picked out 6d4 and 2d12 to give a day/night shift. This boils down 30 options (with some duplicates) to 23 but pulls a bunch of the interesting things off a special list with a sub-1% chance of getting rolled to give more variation and make some of them more likely to turn up, especially at night.

To populate it, following Deathtrap's workflow, first I picked out some known themes I wanted to work in:
Life amidst the ruins
Fecund life
Old insects, once masters here
Local smugglers
Active local dwellers
Refugee traffic
Fey intrustions

Then I had a rummage through other swamp sources to get some ideas and inspirations:
Swamp Encounter table from DMG 3.5
d20pfsrd.com Swamp Tables
The encounter table format as Deathtraps main article
d100 Food Found Foraging in the Bayou
Three d100 Battlemap Generators

I had a first go with the day table, then the special, then the night table as in Deathtraps article then I blocked them into the hidden depths format with the 'day' elements on 11-19 and the night elements on 2-10 and 20-24. Practically, 2-4 and 22-24 are very low probability so they got the weird special stuff. Should things get very strange out in the swamp - full moons? - I can switch to d4+d20 that will bump the likelihood of the odder things and push down the chance of running into 'normal' encounters - all without having to change the table.

Example elements for day-time are local travellers, extreme weather, transport with guards, refugees trekking, locals at work. For nighttime we get cultists engaging in rituals, goblin markets, undead, smugglers and monsters prowling. For the special list we have doors to the feywild, representatives of the big factions about their business (monster-hunting, ruin-delving). These are not clear-cut day/night activities and I am happy for the day-time elements to still potentially turn up at night.

My plan is to couple this encounter table w/ terrain challenges (from Frog Factory's battlemap generator) to get some extra variation in each case. I often forget to make the terrain part of the challenge and particularly in this swamp I want to make it front of mind. For NPC's encountered I will just use step 2 of my NPC personality creation workflow for background/ancestry. Should this become a talking encounter of any depth I would run the other steps for their personality and goals but given this is a wilderness encounter table, their immediate concerns are likely to be as described by the entry - travellers to complete their journey, smugglers to be left alone, guard patrols to confirm all is as their lord wishes, etc.

To wrap up I had a think through some sub-components - some beasts to go in 'Predator beast', monsters to go with 'Monster prowling', what happens during "extreme weather" etc.

Taking this all for a test by pre-genning some encounters:

First (daytime, 6d4) we get Transport w/ Guards + River obstacle - has people so roll up the ancestry and get a group of Owl-lings

Second (daytime, 6d4) we get Extreme Weather + Natural obstacle (Deep Mud) - self explanatory, heavy rains + mud, a pure terrain hazard.

Third (nighttime, 2d12) we get a refugee camp of Okapi-folk, fleeing north from the guild mines to the south.

Last (nighttime, 2d12) we get some insectkin, long absent from the area, why are they back now - these are a bunch of sluglings.

I am satisfied with this - nightfall does not mean everyone exits the area but a lot more strange things are out and about.


  1. As a general question, not as any criticism, may I ask: What is the utility of such in-depth tables? It seems to me there are not enough "hits" on the chance-for-encounter checks generally to justify such subtle gradations in chances of getting rare encounters... like it's a distinction without a difference.

    In my campaign, the Delmor Woods is its own unique area, taking up about 14 total hexes of 6 miles each. If PCs are dismounted for the terrain and going through woods, they can probaby get through 2 hexes a day. Using standard AD&D encounter chances, they will average 2 significant encounters per 3 days. That's only 2 chances to roll on these "what is it?" tables every three in-game days. With only subtle changes ("rare" roll of 10 going from 3% likelihood to 5% likelihood, for example), you'd have to roll many, many times for that subtle change to manifest in a playable difference that was notable to the players as anything other than random. Wouldn't you? And this is in a wilderness area forest, with a high density of encounters.

    And given that any cool encounter worth its salt is, by definition, going to take up at least some chunk of gameplay time, as PCs observe, investigate, strategize, parley, or fight... no matter how quickly the party moves (i.e. no matter how many encounter roll chances their movement generates), the constraints of real world time will mean that you still would be extremely unlikely to *use* such subtle tables enough times for the subtleties to manifest in any meaningful way.

    Am I missing something here? Wouldn't smaller, discrete tables for each time period make more sense. "2d6 on this table during daytime; 2d6 on that one at night; during "chaos time" roll 1d6 on this one bonkers table," etc?

    1. Great questions - thanks for the detailed response. I'll give a short answer now and a more detailed one later - the key driver was to have a day and day/night combo table where much of the same things were about at night because it is a place with a lot of nocturnal locals.

      Single table was also driven by wanting to have everything in one place and I thought since I am doing that, why not put some long haul testing onto this hidden depths type - it is probably not the optimal use but I want to get in some table testing to then maybe revise it / recommendations on using it.

      (Maybe this could be simplified to d12+12 daytime, 2d12 night time)

    2. The longer version is the key part was keeping the day encounters but also having things that become more common at night and others that only come out at night.

      For the day table (6d4) 9 items (places 11-19) cover 90% chance within the 19 item table. For the night table (2d12) 16 items (places 6-21) of a 23 item table cover 89% chance.

      So items, rare in daytime (on places 6-10, 20-24) become more common at night and others appear that *cannot* be encountered during daytime (places 2-5).

      You could well argue that simpler and more or less as effective would be a 1-12 table where the day rolls are 1-6, night is 7-12 and have 'night versions' of the 1-6 entries.

      I like the more probabilistic curve of this as I can tune what is probably after nightfall and what is rare in any circumstances. Your mileage may vary on whether the effort is worth it.

    3. Just saw the latest tables you posted and scrolled back here to see your reply to this. Thanks for the response!

      Love the blog, by the way. I always come by for your Shiny TTRPG links, too.

  2. Very nice stuff! I've been using this to redo my old tired encounter tables - definitely has forced me to approach my tables more deliberately. Also been passing the link around in case other folks might be inspired as well.

    Here's a link to what my chart for the table looks like: https://dice.camp/@chgowiz/109852706685951287)

    The d4/d20 column is for the overall most-likely encounter table for a specific terrain. Useful for generating lairs as well!

    Those lair charts won't show up on the table I'll use at the tabletop - more for my hex contents generation.

    How I do that - Minor lairs are common/uncommon[unusual in your table] creatures so those were moved to a separate column using 2d6, major lairs are rare/very rare, so those also are a separate column.

    For those ultra-rare or perhaps mission specific things, the list of all possible types for each terrain is a separate list as well. I separated that into "most-likely" for use in your tables, and the rest are possibilities.

    1. Interesting - glad you are getting some use out of it. That looks like a huge work you are doing with hex-describe, kudos!