Sir Pigeon's Collection

How I Run Caves of Chaos as a Oneshot

I have run The Caves of Chaos three times as a oneshot and, if I do say so myself, I've gotten pretty good at it. The base of my methods is lifted from this reddit post, but I will provide it here as backup in case the original post is ever deleted.

Original Reddit Post from u/seanfsmith

Despite it being older than myself, I feel a strong pull to B2 Keep on the Borderlands. I've run it a few times now as a one-shot scenario, using The Black Hack, Troika!, and most recently D&D 5e. Here are the tweaks I make so that it becomes a viable adventure site for a 3h30 session.

Hard frame the open

Khedera, a votaress of your order, hired you to guard her while she found the old chaos altar in an abandoned temple within the Caves of Chaos.

That was three days ago.

You don't know if she's alive, or where she is, or where you are.

No wasting time at market, or waiting on a mysterious stranger to accost you in the tavern. This frame gets you straight into the fray, with implied peril but no need for an in medias res fight scene. It's a framing device I stole from a panel about the Pathfinder Playtest by way of gg-no-re podcast, and it's perfect for massive dungeon maps.

If you don't spoil the existence of the chaos temple to your players, you could give the patron a different goal. I've had her delivering a missive to one of the orc tribes (though in this case I've left that message with the PCs rather than on the body of the patron).

Overt objectives

From the start, I tell the players that there are three goals:

  1. Get out into fresh air
  2. Find your patron — or their corpse
  3. Complete the initial goal

I'll usually also tell the players they can level up if they achieve one of these (and even with counting XP in 5e, that still worked {before the owlbear tpk}).

These upfront objectives make this work as a tournament module if you were that way inclined.

Defensible start

The party have been in the caves for at least a few days, so they will have ended up in a defensible position. I default to room 28 (the hobgoblin storeroom) which helps explain why they start with full hp. If you do this a lot and want to mix it up, roll 1d4-1 for the tens and 1d10 for the units and find the closest defensible position to that. It helps if you are at least half a dozen rooms from a cave exit. You can also use 1d6//1d10 to determine the location of the patron.

Reaction rolls and wandering foes

This is a module full of monstrous humanoids with their own agenda and secrets, so to turn it into a mindless bloodbath would be to do it a disservice. For every encounter you have, make a reaction roll. If the system you play doesn't have one, steal this:

Reactions (2d6)

This exact table I've stolen from an OSR blog but the precise one escapes me.

Likewise, if players tarry in a location or make an unreasonable amount of noise, roll 1d6: on a 1, the closest creatures come to investigate; on a 2, the party hear sounds of the nearby creatures.

Speed and usability

There exist a number of maps of the Caves that overlay monster types and numbers in their locations, which allows you to run mostly from that single sheet with minimal lookup. Find your own favourite and use that.

B2 The Keep on the Borderlands is a classic that still holds up as a pleasantly flexible adventure site and with these tips, you don't have to block off a long season at your gaming club.

I'm keen to hear other's stories about running this (or other classic larger modules) as one-shots. What's your experience?

My Modifications

My opening is a bit more long-winded, and it usually goes something like this:

You and your compatriots were hired by the high priestess Zeiglan to accompany her on her journey to the fabled Caves of Chaos. Once there, she sought to cleanse the Caves of their evil, sourced in a temple dedicated to the Unsavory Lords.

Upon arriving at the low valley that houses the Caves, you were accosted by foul beasts. Panicking, you fled into the nearest cave entrance and scurried through dark, twisting passages. You locked yourselves in a storeroom and now find yourself in relative safety, however separated from your patron.

I then go over the three goals of the module: escaping the cave, finding Zeiglan, and completing your original goal. Because I often run this module for new players (or new to OSR players), I also make sure to mention that the monsters in these caves are of notable intelligence and can often be reasoned with.

Rumors

Rumors are one of my favorite aspects of osr play. Unfortunately, Keep on the Borderland's rumors also contain a lot of info about the keep and surrounding area that are not relevant to the caves, or are just not very interesting. This is the rumor chart that I use:

  1. A merchant, imprisoned in the caves, will reward his rescuers
  2. An ogre sometimes helps the cave dwellers for the right price
  3. A magic wand was lost in the caves
  4. F All of the cave entrances are trapped
  5. F “Bree-Yark” is goblin for “we surrender”
  6. F Piles of magic armor are hoarded in the northern caves
  7. F The bugbears in the caves are afraid of dwarves
  8. There is more than one tribe of orcs within the caves
  9. F A powerful magic-user will destroy all cave invaders
  10. Honey is as valuable as gold in the caves

The honey rumor is true, but it has no basis in the original module. I add a few jars of honey with the treasure hoards of the various tribe leaders. The honey is sourced from the cave bees that hive in the owlbear cave. A veritable fortune of honey is available for anyone brave enough to venture into the cave...

Goals

In addition, to keep the module fresh, I include random goals for each PC to achieve.

  1. Slay the Goblin chieftain Grumnof
  2. Free the prisoners of the Hobgoblins
  3. Bring war to the Gnolls
  4. Unite the Goblins and Bugbears in alliance
  5. Ally with the Ogre
  6. Steal treasure from the Minotaur
  7. Inspire the Kobolds
  8. Placate the Orcs
  9. Break the alliance between the Hobgoblins and Kobolds
  10. Collect the head of the owlbear

I have kept most of the goals intentionally vague. Placating the orcs could mean brokering a peace treaty, or it could mean killing all of them before they have a chance to strike.

I also reward players who achieve their goal with a free level up. In most old school systems, this only really equates to a few more hit points, but it is enough of a reward that most players forget their original goal of rescuing their patron and try to beeline towards completing their personal goal.

With slight modification, these goals could become more directly opposed (Ally with the Kobolds, Bring war to the Kobolds, for example). This could provide an interesting challenge for players to work through, trying to come up with schemes that satisfy both goals.

The Temple

After running around the caves rescuing the priestess and completing personal goals, time is usually running short when the party gets around to completing the original quest of cleansing the temple. Because of this, I greatly simplified the temple cave into a single room.

The temple is a 60-foot square room with a high, vaulted ceiling. The walls are adorned with tapestries depicting fearsome demon lords and carnal beasts. Crumbling wooden benches surround a central stone altar, stained black with blood. The entire structure reeks of death, and your torch seems to dim as soon as you enter.

Once the ritual is underway, three demon lords (as wraith) and two beasts (as hellhound) will step out of the tapestries to defend their sanctum. The PCs must protect Zeiglan from the onslaught for 2d4 rounds, when the ritual will complete. Clerics may use their turn to help with the ritual, reducing the total time it takes to complete. Burning the tapestries will burn the creatures, but may send them into a frenzy.

I've had three fantastic games using these methods, and my hope is to continually update this with any new improvements I create.