Back to the… Keep on the Borderlands: A Guide to DnD’s Most Iconic Adventure

Last Updated on January 22, 2023

“The realm of mankind is narrow and constricted. Always, the forces of Chaos press upon its borders”.

Here, at the ragged edge of civilization, stands the last bastion that remains between the human lands and the chaotic, monstrous wilderness: The Keep on the Borderlands.   

Published in 1979, module B2 Keep on the Borderlands was one of the very first adventures written for Dungeons & Dragons by the game’s co-creator Gary Gygax himself. 

This 32-page sandbox module was designed for a party of adventurers between 1st and 3rd levels, who find themselves residents of a keep at the very edges of the human world, a place beset by goblins, orcs, kobolds, and other monstrous creatures who dwell nearby in The Caves of Chaos.

However, while the monsters who dwell within the caves are unquestionably dangerous, they pale in comparison to the true threat lurking beneath the surface.

Unbeknownst to all but a few, an evil cult also lurks in the Caves of Chaos, kidnapping merchants, gathering allies, and even infiltrating the Keep itself.

From the shadows, they plot the downfall of Law and the imminent rule of Chaos over the Borderlands.  

Today, we’re going to be walking you through this classic adventure, exploring some of the lessons it can teach us about being better dungeon masters, and giving you some tips on how you can (and why you should) run Keep on the Borderland for a 5e group today. 

Where Can I Find The Keep on the Borderlands? 

If you’re interested in this module, the pdf and a print-on-demand copy of middling quality are both available from Drive Thru RPG and the DM’s Guild for around $5 and $15, respectively.

If you just want to get your hands on the broad strokes of the module or just feel like reading it for inspiration, this is your best bet. 

If you really like it, the sheer popularity and number of print runs this adventure had actually make it one of the cheapest to buy secondhand when other rarer adventures from the time period can go for serious money. 

You can also pick up a pdf copy of the Tom Moldvay edition of D&D Basic edition from the DM’s Guild if you want to get an idea of the (much simpler) rules that the system uses.

That being said, Keep on the Borderlands does provide a reasonable rules recap of Basic D&D itself — the legacy of a time when all rules weren’t readily available on the internet at a moment’s notice.

If you’re interested in giving old-school D&D a go (and, if you are, this is the module to start with) however, I would recommend checking out Old School Essentials Classic Fantasy by Necrotic Gnome, which is a reformatted and updated republishing of the Basic/Expert D&D rules in a much prettier package and has become the gold standard for the old-school dungeon-delving community in recent years.  

If you want to run Keep on the Borderlands using 5e, you have three options. If you go with either of the first two, however, you may have to prepare your players for the idea that the adventure may not be anything remotely near “balanced.”

  • Convert it yourself, which is totally doable if you’re comfortable rebalancing encounters on the fly and can improvise a monster stat block, spell effect, or magic item on short notice. 
  • If you want a real bare-bones conversion that keeps everything but the ruleset the same, there are a few like this one on DM’s Guild. Fair warning: I’ve not had a chance to read through any of them, so your mileage may vary. 
  • Lastly, if you want a curated, 5e-focused (admittedly expensive) adventure and campaign in the fabled Borderlands, check out Into the Borderlands by Goodman Games. It’s a weighty homage to the original module, reimagined and expanded — kind of like the relationship between Curse of Strahd and I6 Ravenloft

Notes for the Dungeon Master 

Not only was Keep on the Borderlands included in the D&D Basic boxed set from 1979–1982, making it many people’s first foray into the game, but the adventure has been revisited, remixed, and replayed so many times throughout subsequent editions of D&D that it can probably lay claim to the title of “most played D&D adventure ever.”

At its core, Keep on the Borderlands is a “teaching adventure.”

It’s designed to get new players used to sandbox-adventuring, dungeon-delving, and the quintessentially old-school D&D experience of being ignominiously torn apart and devoured by goblins. 

The adventure is also deliberately constructed to help new dungeon masters flex their creative muscles, presenting the materials that form the basis, not just of a short dungeon-delving adventure and some wilderness exploration but a whole homebrew campaign. 

Unlike 5e’s starter adventure Lost Mines of Phandelver, this module doesn’t present a series of encounters, a plot-evolving named NPCs, or even any real concrete details about a setting at all.

It’s a thoroughly agnostic piece of design that gives dungeon masters the freedom to make Keep on the Borderlands fit easily into their own homebrew campaign setting with ease and also challenges them to start making decisions about their own game world. 

While the materials included in the adventure (a fleshed-out keep, several wilderness encounters, and the main dungeon area “The Caves of Chaos”) are enough to support multiple sessions of play, Gygax still leaves a bunch of gaps and blank spaces.

Tunnels lead to nowhere, marked only with the suggestion that the game master invent their own dungeons to fill them, and unless the dungeon master puts the pieces into action, the module can remain remarkably static and devoid of “plot.” 

However, Gygax doesn’t leave the task of preparing the borderlands for the arrival of adventurers entirely up to the DM.

The module also provides a lot of direct advice on how to run a campaign, much (not all) of which holds up more than 40 years later. 

The module itself claims that the keep presents “a microcosm, a world in miniature.” In many ways, I think, Keep on the Borderlands presents the whole of Dungeons & Dragons in miniature — at least, a certain style of D&D

With that, let’s venture along a narrow, rocky track up to the foreboding gates of The Keep on the Borderlands. 

© Wizards of the Coast

The Keep 

The titular Keep itself is a large, heavily fortified structure deep within the wilderness. It’s protected by several dozen men-at-arms, heavy weapons like ballistas and catapults, and its ruler, the Castellan.

In addition to the inner bailey and fortified keep itself, the walls of the structure are overlooked by a number of towers, which largely serve as lookouts and residences for the settlement’s military personnel.

These make up the majority of the Keep’s 27 keyed locations in addition to which there are several notes for the DM about running this settlement and a table of d20 rumors (mostly true, some false). 

Rumors From the Keep 

  1. A merchant, imprisoned within the caves, will reward his rescuers. 
  2. (False) A powerful magic user will destroy all cave invaders. 
  3. Tribes of different creatures live in different caves. 
  4. An ogre sometimes helps the cave dwellers. 
  5. A magic wand was lost in the caves’ area.  
  6. (False) All of the cave entrances are trapped. 
  7. If you get lost, beware the eater of men!
  8. Altars are very dangerous. 
  9. (False) A fair maiden is imprisoned within the caves. 
  10. (False) “Bree-yark” is goblin language for “We surrender!”
  11. Beware of treachery from within the party. 
  12. Big dog-men live very high in the caves. 
  13. There are hordes of tiny dog-men in the lower caves. 
  14. (False) Piles of magic armor are hoarded in the southern caves. 
  15. (False) The bugbears in the caves are afraid of dwarves! 
  16. Lizardmen live in the marshes. 
  17. An elf once disappeared across the marshes. 
  18. Beware the mad hermit of the North lands.
  19. (False) Nobody has ever returned from an expedition to the caves. 
  20. There is more than one tribe of orcs within the caves. 

For a place on the very fringes of human civilization, it manages to play host to a tavern, an inn, a guild house, a chapel, a bank, a smithy and armorer, a couple of basic stores, stables, and several private apartments for the wealthier folk traveling through the Keep. 

Indeed, there are a surprising number of travelers — including merchants, their families, and even a delegation of priests — passing through the keep at any one time, which also includes a number of aspiring adventurers.

The PCs fall into this final class of visitors and, assuming they don’t make total fools of themselves at the gate, are welcomed into the social fabric of the keep with open arms. 

Rather than summarize all the important NPCs and locations in the Keep, here are three major “threads” or elements of the Keep that are important or useful to a DM but may not be immediately obvious the first time you read the module. 

A Stronghold of Law, Not of Good 

In Basic D&D, there was no Good/Evil axis to the alignment chart. You were either Lawful (which means you were probably also good, selfless, and in favor of civilization), Chaotic (which meant you were probably evil or at the very least selfish), or Neutral (which meant you were somewhere in between).

It’s… kind of bad, unless you treat the forces of Law and Chaos more like cosmic forces taking an active part in the material universe.

Law is a force of preservation and order, and Chaos is a force of unbridled entropy and destruction. Through this lens, I think you could make it work. Otherwise, things start to get kind of problematic. 

The module assumes (or, more accurately, beats you over the head with the idea) that because the keep is a fortress of Law in a chaotic (“savage”) wilderness, the player characters will unflinchingly support the forces of Law in their noble quest to… uh, launch raids into the Chaotic “monster” houses and murder them for their treasure. 

Tom McGrenery from the Fear of a Black Dragon podcast makes the point that “more than any other genre, old school D&D adopts the format and tropes of the cavalry western.”

Of course (as W.F. Smith, author of the outstanding OSR blog Prismatic Wasteland, notes in his blog post “The Keep on the Borderlands is Full of Lies”) recasting the heroes as a ragtag band of John Waynes and Burt Lancasters heading out into the wilderness to slaughter Apaches in their beds kind of doesn’t feel so great. 

I’m not saying that you need to present the orderly police state of the Keep as the new villains of the piece, but extricating the Lawfulness of the location from the Goodness implied in the original text will probably lead to a richer, more rewarding game.

It will also make things a little more interesting when your players bump up against the next big thread… 

The Cult of Evil Chaos

It’s a real “blink and you’ll miss it” thing, seeing as all the storytelling in Keep on the Borderlands is done through the emergent environment of the Caves and the Keep, rather than in a summary up front (that space is dedicated to reams of social Darwinist pro-Keep propaganda. Grab your torches and your pitchforks, adventurers; there’s orcs that need a-murderin’!), but the Cult of Evil Chaos have already infiltrated the Keep. 

There’s a visiting priest staying in one of the private apartments who, along with his two creepily silent acolytes, is a secret spy for the cult.

He’s jovial and polite and generally wants to insert himself as a potential traveling companion of the party (who would possibly turn down the assistance of a friendly cleric with cure light wounds memorized, after all?) but will turn on them immediately upon entering the Caves. 

A lot of people criticize this module for being too static, but the presence of the secret cult cleric hints at motion and a plot by the Keep to attack the biggest outpost of Law in the area.

Why else would a bunch of monstrous humanoids who hate each other be cohabiting in the same cramped ravine as a shrine of evil chaos cultists not two miles away? But more on that in a minute. 

You don’t have to “activate” the Cult of Evil Chaos’ sleeper agent immediately or have the minions of Chaos storm the Keep right way, but he’s a great way to disrupt and sabotage the players (definitely make him the one to tell the players the false rumor about the goblin word for “we surrender,” which turns an otherwise crappy trick by the DM into an important clue for the players) and the Keep’s other inhabitants as you let the threat of Chaos loom ever larger. 

Depending on whether I want to make the Cult (and Chaos as a force in general) a major part of the adventure, I like to have the priest working in conjunction with the chaotic raiders outside the keep (see below), signaling them of the PCs’ movement, patrols, and anything else where having the bad guys be a little forewarned can help make an encounter all the more dangerous. 

The Castellan 

Lastly, the lord high Castellan in charge of the Keep is an interesting character that you can interpret in a number of ways that have a lot of knock-on effects when it comes to interpreting the module as a whole. 

Is the Castellan a brutal conqueror here to win political points in a far-off court by subjugating more of the lands?

Is he a disgraced general of a powerful empire here as penance for a critical defeat?

Is he a corrupt (or just bumbling) backwater functionary who thought this would be a quiet, out-of-the-way posting where he could drink himself to death with quiet dignity? 

What does he think about the rumors of a growing force of monsters in the hills? What would he be willing to give adventurers who help him solve his problems? What would he do to a band of dirty treasure hunters who got on his bad side? 

Figuring out the Castellan’s “deal” is a big part of preparing the Keep, but your players won’t have access to them immediately, of course.

They’ll need to perform some great deeds (or make a cash donation of 1,000 gold pieces or more) in service to the Keep before they get invited to dinner.

Then, if they’re well behaved, the Castellan will give them a “special mission,” which the DM is instructed to come up with. 

The mission is probably expected to involve the Caves (assassinating the leader of one of the monster factions or recovering a particular item are both easy enough), but it could be anything.

The beauty of Keep on the Borderlands is just how easy it is to bolt other adventures onto the side of it.

I’ve used the Castellan’s special mission as a way to send players off into other adventures entirely, like The Secret of Bone Hill (an idea I stole from the excellent Borderlands play report series by There Could Have Been Snakes “Keep on Ye Olde Lands”), but the adventure advises you to just pick something difficult but not beyond the scope of the players’ current level. 

The Wilderness 

There are a few miles of untamed wilderness between the Keep and the Caves of Chaos, and there are more than a few opportunities for a low-level adventuring party to get themselves horribly killed without ever setting foot in the dungeon (where they’re almost certain to get horribly killed almost immediately). 

There are four main encounters in the area surrounding the Keep: a burrow full of lizardmen, a deadly spider nest, a raider camp, and the home of a mad hermit and his pet mountain lion. 


Camping in the wilderness doesn’t carry the usual risk of a random encounter with a wandering monster, but instead, PCs have an increasing x-in-6 chance of being stumbled upon by the monsters from a particular encounter, depending on how many map squares away from that encounter they are. 


Moving through the wilderness to the Caves themselves should actually be a somewhat easy process, as all the players have to do is follow the road for a while and then turn left before they fall off the map. 

Personally, I like to make the expanse between the Keep and the Caves a little more labyrinthine.

You can check out my rules for labyrinthine spaces here, but essentially, the players need to make a number of successful checks (usually three) with each failure prompting a roll on the encounter table. 

I like to use X-in-6 chance rolls with 1-in-6 being the standard and the target number increasing for things like the presence of a ranger and previous successful trips between the Keep and the Caves, but you can do a Survival check or anything else you like.

Mound of the Lizard Men 

A tribe of 10 “exceptionally evil” lizardmen and their offspring live in a large muddy mound in the middle of a swamp south of the keep. They come out at night to hunt, but otherwise, they stay inside and don’t bother people. 

Exactly what makes these creatures “exceptionally evil” is something of a mystery as they only ever emerge during daylight to forage for food, and they are too few in number to threaten a larger party.

The treasure in their den hints that they might attack, kill, and eat the odd traveler, but by that standard, they’re basically indistinguishable from the average wildlife in central Florida. 

Spiders’ Lair 

Two Black Widow spiders (which one has to presume are much larger and more dangerous in the D&D world as they have more than twice the hit points of the average 1st-level adventurer in Basic D&D) have spun webs big enough to catch and eat humanoids and other large prey between the trees. 

In the undergrowth nearby are the remains of the elf from the Keep rumor table. All his gear is ruined apart from a +1 magic shield in much need of restoration. 

Raider Camp 

A dozen chaotic fighters had made camp close enough to spy on the Keep but far enough away to avoid notice by patrols.

They have meat and wine and are probably the most interesting encounter in the wilderness because, much like the threads found in the Keep section, they’re a chance to say something about your version of the Keep and your version of the Borderlands. 

In a game where the Lawfulness of the Keep borders on cruelty and colonial oppression, the raiders read like a description of Robin Hood and his Merry Men from the perspective of the Sheriff of Nottingham (thanks again, Prismatic Wasteland) and could be useful allies for a party who find themselves in opposition to the Castellan and his forces. 

Likewise, in a campaign where the Cult of Evil Chaos takes center stage as antagonists, the Raiders can easily become spies, assassins, and saboteurs — a party of murderous infiltrators who are ready to be let into the Keep by the evil priest to assassinate the Castellan at the feast being held in the players’ honor. 

Maybe they’re a rival adventuring party who decided it was easier to rob other adventurers on their way home from the Caves than it was to venture into the Caves themselves.

Whatever you do with them, making them simple “raiders” is a waste of their potential.

The Mad Hermit  

Possibly a fun roleplaying opportunity and definitely one of the most dangerous combat encounters in the adventure, the Mad Hermit is a thief masquerading as a local friendly neighborhood holy man, who is secretly a thief who will “suddenly turn on the group when the opportunity presents itself, striking from behind and calling his ferocious “pet” to his aid.” 

The hermit’s “pet” is actually a mountain lion, which always wins initiative contests and can make three attacks per turn.

It’s a terrifying creature that, in concert with a 3rd-level thief, is more than capable of wiping out a low-level party. 

Mad Hermit
© Wizards of the Coast

The Caves of Chaos 

“You have been passing through the forest for some time, as it grows denser and gloomier, until the misshapen trees and grasping briars suddenly give way to a ravine. Its walls—dark, streaked rock mingled with earth—rise steeply to either side to a height of about 100 feet. 

Clumps of trees, some dead, stand even on the slopes. The opening you are in is about 200 feet wide, and the ravine runs at least 400 feet west.

At varying heights on all sides of the ravine are the mouths of caves. The sunlight is dim and the air is dank, with the oppressive feeling of something evil watching.

A flock of ravens rises croaking from the ground, the terrain magnifying the beat of their wings and their cries into a horrible sound. 

Among the litter of rubble, boulders, and dead wood on the ravine floor, you can see bones of humanoids, animals, and other creatures. 

You have discovered the Caves of Chaos.”

The Caves of Chaos are a network of interlinked mini-dungeons accessed by a series of cave mouths in the walls of a ravine.

Inside dwell several factions of monstrous humanoids, a minotaur in a magical labyrinth, a rampaging owlbear, and several other dangerous creatures who would happily make a meal of an unsuspecting adventurer.

It is also the home of the Cult of Evil Chaos. 

The Caves of Chaos occupy pages 14-23 of Keep on the Borderlands and starts with notes for the DM on running the caves, restocking monsters in between party excursions, tribal warfare between different monstrous factions, and how to show that the monsters learn from experience. 

The rest of the dungeon is comprised of 64 keyed locations grouped into areas labeled A through K, which are linked to the nearest dungeon entrance and the faction or creature occupying them. 

Many of the areas interlink with one another, and it’s possible for a party to move from one area to another by accident.

As a general rule, monsters living higher up the cliff faces are more dangerous than ones living on the ravine floor, although there are exceptions. 

A. Kobold Lair 

A clamoring horde of small dog-faced creatures (kobolds didn’t become lizardlike or draconic until later editions, making them more like diminutive gnolls in Basic D&D) have built pit traps to keep them safe and tamed a nest of almost 20 giant rats to keep them safe.

The Kobold chieftain (Area 5) is so huge and “powerful that he fights with a battle axe,” meaning he’s probably about 3’ tall. 

B. Orc Lair 

The first tribe of about 20 orcs is protected by an ingenious wall of shrunken orc, monster, and human trophy heads, one of which is actually a living orc who stands behind the wall with his head through a hole, allowing him to secretly keep watch on the entryway. 

C. Orc Lair 

Rather than relying on a continual watch, these orcs use a network of thin tripwire alarms.

There is roughly the same number of orcs in this group as in Area B, and even though they are by no means friendly, the leaders of the two tribes have a secret tunnel between their caves that they use to meet and negotiate under cover of darkness. 

D. Goblin Lair 

The goblin tribe lives in worked stone tunnels rather than the natural caves that the orcs call home.

More than 30 goblins live throughout the various rooms, and they have an arrangement with the ogre in Area E, whom they can hire in case of an adventurer incursion.

There is a secret trapdoor in the goblins’ storeroom through which the hobgoblins from Area F regularly sneak to steal the best bits of food. 

E. Ogre Cave 

A foul and fetid cave that’s saturated with a sour odor. Players walking inside come across what appears to be a giant sleeping bear, but it is actually just the ogre’s rug.

The ogre — who is a deadly threat to a low-level party but can most likely be bribed with valuables or fresh meat — awaits further in the cave near the secret entrance to the goblin complex. 

F. Hobgoblin Lair 

Behind a macabre, skull-lined cave and a stout oak door, the hobgoblins live in relative peace — although they frequently skirmish with the orcs across the ravine.

Their torture chamber, infant playroom, and food storage rooms are all the same room, which should give you all you need to know about their level of chill.

Tied to a chair, the PCs can find a “plump, half-dead merchant” the hobgoblins were clearly planning to eat. This can generate some serious favor with the guild back in the Keep if he is returned in one piece. 

G. Shunned Cavern 

Easily one of the most dangerous areas — so much so that all the other monsters in the ravine avoid it.

The Shunned Cavern is home to a Gray Ooze and an Owlbear, both of which (along with some giant rats) are likely to come to investigate any noise near the entrance. 

H. Bugbear Den  

The fifth faction in the Caves, the Bugbears live pretty much at the top of the food chain and content themselves with picking off and eating any wounded or stragglers from the other groups.

They keep several kobolds, goblins, hobgoblins, and orcs as well as a few humans, a dwarf, a pair of elves, and a wild-eyed barbarian adventurer in their slave pens, who can make excellent allies in a pinch. 

I. Caves of the Minotaur 

Although not especially labyrinthine, these caves are the subject of a unique spell that forces anyone who enters them to completely lose their sense of direction.

They are also home to a chainmail-clad minotaur who is routinely hired by the bugbears and paid in juicy humans to eat. 

J. Gnoll Lair 

Vicious demon dogs make up the final monstrous faction in the Caves of Chaos, and their lair is a largely unremarkable series of guard rooms — although their storeroom contains a leaking barrel of bizarrely delicious ale that can cause adventurers to throw caution to the wind and spend up to 40 minutes drinking it, talking loudly, and singing songs like they’re the foolish protagonists in some Greek fable. 

K. Shrine of Evil Chaos 

Hordes of silently waiting skeletons and shambling zombies, evil clerics, altars draped in black silk, blood-red stone temples, cursed statues, and other such excellent trappings of an evil cult await in the final section of the Caves.

In addition to the cultists and undead, there are also several prison cells containing the cult’s prisoners, including a captured medusa, which the head priest plans to blind and sacrifice in an upcoming ritual to a demon.

Grisly stuff.  

The Cult of Evil Chaos are the unspoken secret bad guys of the whole adventure, and discovering their presence in the caves is probably the best aftermarket solution to the question… 

What Are All These Monsters Doing Here?

The criticism I see leveled at Keep on the Borderlands most often is that the Caves of Chaos contain six discrete factions of monsters, all living (and fighting) together in a single small ravine, quite near to a whole Keep full of soldiers and adventurers who want them dead. 

Not that realism is the guiding light of a good D&D adventure, but plausibility should at least be maintained, and, I think, the Cult of Evil Chaos is the way to do it.

If you start to look at the plot beneath the surface… the cult’s temple in the hills, the priest and his acolytes sent to spy on the Keep, the chaotic Raiders in the nearby hills, the captive medusa and the upcoming ritual… the Cult of Evil Chaos is planning to attack the Keep on the Borderlands. 

Obviously, this is no mean feat. The Keep is well fortified (stone walls, towers, ballistas, etc.) and well defended by professional soldiers.

A sizable force would be needed to take it in open warfare… perhaps, say, a few hundred goblins, kobolds, orcs, hobgoblins, bugbears, and gnolls?

Maybe even with an ogre thrown in with a minotaur and an army of undead for luck. Or perhaps a soon-to-be-summoned demon? 

The Cult is gathering power and trying desperately to hold together a fractious, chaotic army of ragtag creatures until it can launch its final assault on the Keep.

If you start to view it that way, the whole module starts to make a lot more sense. 

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