Go to Part 1

In (Re-)Running the Megadungeon, we looked at how you can evolve a megadungeon over time, actively playing it just like the players actively play their characters: You repopulate it. You modify it. You roleplay the inhabitants.

In the process, you create a dynamic experience that’s constantly surprising and delighting (and terrifying) your players, while also dramatically extending the amount of high-quality playing time you can get out of surprisingly simple prep.

Now I want to return to the series, flip things around, and take a closer look at how the players can evolve the megadungeon over time.

(If you’re here because you’ve innocently just started reading the series: Alert! The last link skipped you forward in time by a dozen years! Don’t worry! Any resulting temporal anomalies will resolve themselves shortly without disrupting your personal continuity.)

INTO CASTLE BLACKMOOR

Of course, almost any action the PCs take in a megadungeon will affect its future form. This is, after all, a back-and-forth dynamic. Killing all the lizardmen is what allows the elementalist to move in and set up shop, right? But what I want to spotlight today are the cases where the PCs more deliberately (and proactively) transform the dungeon.

Most of the examples we’ll be looking at here come from the open table campaign I ran in Castle Blackmoor, the original megadungeon created by Dave Arenson in which the modern roleplaying game was invented, and from which modern D&D was born. Running Castle Blackmoor provides a deeper look into how I set up and ran the campaign, but all you really need to know for now is that Castle Blackmoor sits atop a hill and beneath it lies the dungeon.

When the PCs enter the dungeon, this is the first room they encounter:

Speaking frankly and from experience, this room is incredible.

First, it’s too large for normal torchlight to fully illuminate it. So you’re immediately thrown into a fog of war.

Second, even if you have a more powerful light source, the shape of the room means that you can never see the entire room when you first enter it, no matter which entrance you use. Whether you’re entering the dungeon for the first time or returning to this chamber in the hopes of escaping to the daylight above, you can never be entirely certain if the room is empty… or if there’s something lurking just around the corner.

Third, and most importantly, there are ten doors. (Plus three more secret doors, including two hidden in the columns that aren’t indicated on the map here.) Literally the moment a PC steps into the Blackmoor dungeon, the player is confronted by the absolute necessity to make a choice: Which door are we going to open? Where is our adventure going to take us? The DM isn’t going to make that decision for you. You’re in control of what happens here.

Even if you have literally never played a roleplaying game before (and I’ve run Blackmoor for such players), this room inherently pushes them into actively engaging with the scenario while simultaneously teaching them that the game is about the choices they make.

The entire room screams player agency, and then holds forth the promise of endlessly varied adventure (every time you come back, you can pick another door). It tells you literally everything you need to know about Blackmoor, about dungeons, and about the game in an instant and without ever explicitly explaining any of it.

Playtest Tip: Describing the shape of this room verbally is impossible. If you’re playing in the theater of the mind, nevertheless make a rough sketch of its shape and be prepared to show it to the players. I kept a copy of the sketch I made clipped to my Blackmoor maps. But I digress.

The reason I bring it up here is that it’s a really simple example of player transformation of the dungeon: Confronted with all those doors, the players were confusing themselves when discussing their options and making their maps. So for the sake of clarity, they labeled the doors: First on the maps and then, shortly thereafter, in the dungeon itself.

Starting with the door to the left of the staircase, they labeled them alphabetically, A thru J. (Hilariously, however, the group who first did this missed one of the doors, so “J” ended up out of sequence.) The doors were first labeled in chalk (which one of the PCs had purchased), and this was later made more permanent when mischievous sprites in the dungeon started erasing the labels.

In doing this, my players were unwittingly echoing what Dave Arneson’s original players had done nearly fifty years earlier: After arbitrarily choosing the northwest door, they apparently fell into the habit of using it to mount most of their expeditions. It became known as the “Northwest Passage,” and eventually one of the players hung a wooden placard over the door with this name written upon it.

A later group took this even further, making coded markings at the various stairs in the dungeon to serve as navigational aids. These codes actually referred back to the door names (so for example, a staircase labeled G2 indicated that they were on the second level and this staircase would take them back to Door G… assuming that they hadn’t gotten lost or confused and encoded the wrong information).

TANGLEFUCK

Becoming lost and confused reminds me of another fun story from my Blackmoor table.

Looking at this section of the dungeon on the map, it seems fairly straightforward, although you may note Arneson’s devilish penchant for oddly angled diagonals.

One evening, however, a group headed into this section of the dungeon and began going in loops. Their map rapidly metastasized (because they were mapping the same corridors over and over again as if they were new passages), and by the time they realized what was happening they were hopelessly disoriented. They began making navigational marks (labeling walls and intersections), but because they were already lost, most of these marks were incorrect, contradicted each other, and

Fortunately, everyone at the table was having a great time with this, laughing uproariously whenever the PCs circled around, confident they were breaking new ground, only to come face-to-face with their writing on the wall or floor. (At this point, the sprites had already begun messing with the door labels, so there was also paranoia that something was here in the hallways with them and was altering their signs.)

One memorable moment came when they arrived at an intersection, confidently declared that they had gone left the last time they were here, so they were going to go right this time and they would definitely get out! … except that wasn’t right, and so they ended up looping back around and coming back to the same intersection again.

“Okay, so we definitely went left last time, so we need to go right this time.”

They did this four times!

Ironically, the door out was, in fact, immediately to the left of that intersection.

When they finally figured this out and, with great relief, headed through the door, one of the PCs stopped, took out some charcoal, and wrote in large dwarven runes on the wall, as a warning to all who might come here in the future: TANGLEFUCK.

And so this section of the dungeon came to be known forever after.

OTHER TALES FROM THE TABLE

In another campaign I ran, the PCs began collapsing tunnels to prevent anyone else from entering a section of the dungeon haunted by a malevolent force. In yet another, the PCs memorably hired a group of mercenaries to guard the entrance to the dungeon and prevent other adventurers from entering. (An effort which met with mixed success.)

These player-led transformations are particularly wonderful in an open table: Because there are other players exploring the world who were not part of the group which made the original changes, those players get to discover (and, conversely, leave their own transformations for others to discover in turn).

These long-term interactions across multiple sessions and groups can pay off in a multitude of gloriously unexpected ways. For example, I mentioned that my Blackmoor players began encoding navigational markers. But there were actually multiple characters who had the same idea, which meant that different groups were encoding information in different, overlapping ways. And then there was the memorable group where only player had previously been part of an encoding group… and he screwed up the code. So not only did that group leave miscoded marks, but the other PCs in the group — who had been taught the incorrect method — carried that mistaken information into other groups and spread it even farther.

So who made these markings? Another group of explorers? Or monsters looking to trick the interlopers?

The fact that there are other real people interacting with this shared game world and that you can see the consequences of their actions and they can see the consequences of yours is intoxicating. (And can easily lead to motivating players to make even larger and more meaningful impacts on the game world.)

Even at a dedicated table, however, player-led transformations are great. It’s basically GMing on easy mode: You can often just lean back and take notes.

More importantly, the players are metaphorically throwing you a ball. They’re inviting you to play with them, and in the process making it a lot easier for you to generate your own responses that will continue to evolve the dungeon. (Like those sprites altering the navigational markings.)

All you need to do is pick up the ball and throw it back.

FURTHER READING
Treasure Maps & The Unknown: Goals in the Megadungeon
Keep on the Borderlands: Factions in the Dungeon
Xandering the Dungeon
Gamemastery 101

One of the key concepts of “(Re-)Running the Megadungeon” is that the goal of the adventure is not and cannot be to “clear the dungeon”. Such a goal would be as meaningless as a World War II game in which the goal was, “Kill all the Nazis.”

(I suppose, in a general sense, you actually could hold such a goal. It would be something like the ultimate instantiation of the hack ‘n slash campaign: There’s a dungeon over there. Go slash at it for awhile. The important thing, however, is that one cannot reasonably expect to achieve that goal. That’s just not going to hack it.)

The loss of this clear-cut goal is problematic because “clear the dungeon” has long since become the default tactical solution for virtually every scenario in D&D. Oh, it’s usually gussied up a bit. But you’d be surprised at how often everything boils down to “clear the dungeon”. For example:

• “The forces of chaos are marshaling for an assault on the last bastion of civilization?” “How do we stop it?” “Go to the Caves of Chaos and… clear the dungeon.” (B2 Keep on the Borderlands)
• “The corrupt mayor is planning to release the Yellow Sign and drive Freeport into madness!” “How do we stop it?” “Go to the Lighthouse and… clear the dungeon.” (Freeport Trilogy)
• “Slavers are kidnapping people off the streets!” “How do we stop them?” “Go to the slave pits and… clear the dungeon.” (Scourge of the Slave Lords)
• “The Giants are arming for war!” “How do we stop them?” “Go to their steading and… clear the dungeon.” (Against the Giants)
• “Kalarel is trying to summon something terrible from the Shadowfell!” “How do we stop him?” “Go to the Keep and… clear the dungeon.” (Keep on the Shadowfell)

There’s nothing terribly wrong with this formula, of course. As you can see, it can be easily mapped to any number of potential crises. It has the virtue of being easy to set-up (Bad Guys X are trying to do Bad Thing Y and they can be found at Bad Place Z). And the players generally know exactly what they’re supposed to be doing (“Wipe them out, all of them”).

However, it does have the rather unfortunate side-effect of inherently funneling everything through the combat system, drastically narrowing the range of potential gameplay. And when you attempt to apply this default formula to the megadungeon it creates two major problems:

First, it’s a grind.  If your goal is to “wipe out all the bad guys” in a dungeon filled with bad guys, then the megadungeon boils down to a very simplistic dynamic: You go into the dungeon, empty as many rooms as possible, and then retreat. Then you go back and  you do it again. And again. And again. And again.

Second, the formula is inherently designed to use up material, whereas your goal with the megadungeon is recycle, reuse, and remix material. And the more you restock the dungeon while your players are trying to destock it, the more of a grind the whole thing becomes.

SETTING A DEFAULT

Having set aside the default mode of “clear the dungeon”, what are we to replace it with?

It’s not unusual at this juncture for someone to say, “Exploration.” Go poke around in the corners of the dungeon because you’re curious about what might be hanging out down there.

It’s not a bad suggestion, per se. But in my experience, exploration for the sake of exploration can be rather aimless. It lacks the necessary specificity to function as the driving force behind a campaign. I suspect this is because it doesn’t provide a strong enough criteria for decision-making: If you’re standing at an intersection in the dungeon and your goal is merely “to explore”, does it really matter which way you go? Not really. You’ll be exploring whichever way you go.

But “exploration” remains a compelling concept. Is there a way we can make it a more clearly defined goal?

Gold.

Here I once again find myself looking back to the earliest versions of the game, when the default method of play was not “kill the monsters”, but instead “find the treasure” — i.e., exploration geared towards a more specific end. And, notably, a specific end which — unlike “kill the monsters” — doesn’t pre-suppose the tactical and strategic means of success. (“Kill the monsters” implies blasting them with spells and poking them with pointy bits of metal. “Find the treasure” might mean killing monsters… but it could also mean sneaking past them, negotiating with them, distracting them, hiring them, tricking them, trading with them, or any number of other possibilities.)

TREASURE HUNTING

“Find the treasure”, in its most generic form, may not be terribly compelling. But it is sufficient for reliably getting the PCs to the entrance of the dungeon (and universal enough that it provides little meaningful constriction in terms of the types of characters that can be created; of course, there’s also no reason why a player couldn’t find a more unique goal for their PC).

Before one simply writes off “find the treasure” as bland pablum, however, consider that in its more specific forms “find the treasure” has served as the basis for some of the great stories of our time (or any time): Raiders of the Lost Ark, The Maltese Falcon, The Hobbit, The Illiad, The Golden Fleece. They’re all stories about treasure-hunting.

And OD&D builds a method for building towards that specificity right into its rules for procedural content generation: Treasure maps.

If you’re randomly generating treasure troves using the OD&D guidelines, then most intelligent foes will have a 10-15% chance of having one or more treasure maps. These can, of course, take many forms. (The Judges Guild Book of Treasure Maps supplements included everything from journal entries to scribbled notes to careful exemplars of cartography.) But the point is that a treasure map points you towards some specific treasure: You are no longer just poking around for gold in the general sense; you are specifically seeking for “the Tombe of Aerthering who is called DAMNED” (to take one example).

SPECIFIC DUNGEON GOALS

Moving beyond that, the point of setting a default goal (like “find the treasure”) is not to limit the game, but rather to provide a baseline to ensure that gaming happens. The point isn’t to say “you will go treasure-hunting”, but rather to say “if you can’t think of anything better to do, we’ll default to treasure-hunting”.

More generally, once you’ve used your default goal(s) to get the PCs into the dungeon complex, more specific goals will generally tend to accumulate on their own. In my Caverns of Thracia game, for example, a deep grudge quickly settled in against the minotaur who kept cropping up on an irregular basis. (He had killed or maimed more than a dozen PCs, so the grudge is probably understandable.) There were cheers at the table when he was finally cornered and killed in a recent session.

Have we arrived back at “killing the bad guy” as a viable megadungeon goal? Sure. (You didn’t think I was advocating for combat to be taken out of D&D, did you?) It’s not necessary to completely abandon the “there are bad guys, go get ’em” formula. But it may require a little more subtlety than that mail-order course on strategy from Palpatine University might suggest. “Wipe them out, all of them” might cut it if they’re the only guys in the neighborhood, but picking a fight with every humanoid tribe in the region because you want to put the cultists on level 4 out of commission probably isn’t a great idea.

Which begins to move us in the general direction of a more general precept: While it is necessary to maintain some sense of mystery regarding the depths of the megadungeon (as drawing back that veil of ignorance is one of the rewards for playing in a properly compelling megadungeon), it’s also important to foreshadow those depths by revealing certain details. These details, in turn, become goals for the PCs to achieve.

(The methods by which this foreshadowing can occur are essentially limitless: For example, the PCs may know that Black Donagal fled into the depths because they saw him do it. They may learn about the minotaur court by questioning a prisoner. They may find a map indicating the location of the Hall of Golden Maidens (if only they could identify one of the landmarks on their map). And so forth, not to mention divinations and magical visions.)

At this point, we can successfully return to the idea of “exploration” as a meaningful goal. Because while “exploring for the sake of exploring” is unfocused, exploring because you want to find the Tunnel of Black Rainbows is more than specific enough.

But we don’t have to stop there: The features of a megadungeon are people, places, and things. And all of these features can be foreshadowed and, thus, become goals. And out of people, places, and things every story in the history of the world has been told.

The default gets them playing. But once they start playing, there’s no limit to the things they can find or the goals they can discover.

In “(Re)-Running the Megadungeon” I talked about how to keep a dungeon complex fresh by restocking the room key and using wandering monster tables as a form of low-tech procedural content generation. In “Wandering Adventures” I talked about how the OD&D wandering monster tables could be used to generate entire adventures. Now I want to build on those ideas by touching on the basic concept of factions in the dungeon.

To immediately boil the idea down to its core: If your dungeon has a life beyond the activities of the PCs, it is much easier to revitalize the dungeon between delves. The life of the dungeon will naturally generate the ideas necessary to restock the dungeon (and, thus, carry a lot of the weight for you). This becomes even easier if the dungeon contains multiple, independent factions. (And even moreso if these factions are openly hostile to each other.)

Nor does this have to be something that you need heavily pre-plan. It can largely just be a matter of keeping one eye on it during your restocking process: “Okay, the PCs killed 70% of the orc population on Level 3. Who can take advantage of that? What will the Orc King’s response be? Actually, wait, they killed the Orc King. Have the orcs broken into factions? Could the Red Prince (I just made that name up) have allied with the goblins on Level 2 to push his claims? How will the other orcs feel about being asked to co-exist with lowly goblins? Will they turn to the Voodoo Necromancer (just made that up, too) who was once the Orc King’s advisor?” That’s about 15 seconds of brain-storming. Follow it up with a couple minutes of actual prep and you’ve got orc-and-goblin warbands with faces painted bright crimson squaring off against orc warriors ‘roided out on alchemical strength-boosters wearing the bone fetishes of the Voodoo Necromancer. It doesn’t even really matter if the PCs get involved in the actual politics of the situation: Even if they just hack their way through these orcish factions, they’ll (a) recognize that the dungeon has changed in their absence and (b) get some unique and interesting hacking out of it.

(You can see a similar real-play example of this in Delve Seven of “(Re-)Running the Megadungeon” when the elementalist gets killed.)

So, obviously, there’s nothing wrong with winging it. In the process of winging it, however, I’ve found it generally useful to prep two key pieces of information:

1. Identify each faction.
2. Identify the territory controlled by each faction.

Most of the time, it’s not necessary to get really obsessive with this. For example, in the Caverns of Thracia I don’t really have much more than a general sense that “the cultists control this chunk of the map”, “the lizardmen control these rooms”, “the anubians are based out of this complex”, and the like.

My understanding of the complex is fairly amorphous, and putting more detail into it is probably counter-productive: It’s unlikely to ever be noticed by players, it’ll bog down your prep, and it’s rarely representative of the fairly amorphous nature of contested territory. Precision will also tend to bog down your ability to flexibly interpret the results from your random encounter tables.

(Of course, if you’re designing a scenario in which particular focus or importance is placed on factional play, more detail may be merited.)

RANDOM FACTION INTERACTION TABLES

With that being said, it might be valuable to build some quick, light tools that will allow you to procedurally generate the ebbing shifts of factional fortunes in the dungeon. For this purpose, let’s turn to the Caves of Chaos from the classic B2 Keep on the Borderlands.

For those unfamiliar with this module, the Caves of Chaos are particularly useful for this purpose because they’ve already been conveniently split into factions: Essentially you’ve got a small valley full of caves, with each cave leading to an interconnected system of caverns and serving as the lair for one of several chaotic factions. The factions are:

(“Wandering Adventurers” refers to an NPC party entering the Caves of Chaos.)

FACTION CONFLICT CHECK: After each visit to the caves by a party of PCs, make a faction conflict check. Roll 1d6. On a roll of 6, conflict has broken out between the factions. Roll twice on the faction table to determine which two factions have come into conflict. (If you roll the same number twice, either re-roll or assume some sort of civil strife.) Then roll on the Conflict Resolution Table:

Stalemate Skirmish: The factions are largely unaffected by the conflict. Their forces may have been reinforced, or you may wish to subtract 1 or 2 members from one of their encounters. (The conflict may leave them ripe for alliances against their recent foes; or leave a chamber showing recent signs of conflict; or a couple of corpses tossed onto the valley floor to be feasted on by the owlbear.)

Faction Damaged: A damaged faction has suffered losses equal to roughly 25% of their strength. Subtract 1d4 members from each encounter (keyed or random) with that faction.

Faction Crippled: A crippled faction has suffered loses equal to roughly 50% of their strength. Eliminate entire encounters or subtract 1d12 members from each encounter (keyed or random) with that faction.

Faction Destroyed: A destroyed faction has been eliminated. Their lair may lie empty, be occupied by the other faction involved in the conflict, or restocked randomly. Their population has been killed, driven off, or enslaved.

Factions Unite: The two factions have allied with each other. (One of the leaders may have been killed. The alliance may be for some short-term goal. Or the populations might be fully intermixed between the lairs.)

USING THE TABLES

Like a random encounter table, the output here is designed to be flexibly interpreted. Once again, the Caves of Chaos are great for this sort of thing because it already includes some short notes regarding the relationships between the factions. (For example, the owlbear is described as having recently munched on some gnolls. The two orc chieftains have a secret meeting room that only they know about. And so forth.)

Mostly for the fun of it, I’m going to roll up a couple actual examples using these tables. We’ll start by assuming that I’ve just rolled a “6” on my Faction Conflict Check and go from there:

1. DETERMINE FACTIONS: I roll 1d12 twice, generating 9 and 5. That’s the Minotaur and the Ogre.

2. DETERMINE OUTCOME: I roll 1d8 and get 8. That’s Factions Unite.

3. INTERPRET RESULT: The Minotaur and the Ogre are the two solo factions in the Caves. (There’s only one Ogre and one Minotaur.) Scanning their entries, I see that the ogre is willing to sell his services to the highest bidder and the minotaur has a lot of money. So let’s say that the minotaur has hired the ogre for some purpose. What could it be? Well, the minotaur is willing to help the bugbears if they pay him in slaves. What if the bugbears cheated the minotaur and now he wants a little help to get the payment he feels is his due? That sets up a scenario where the PCs could arrive in the valley to see bugbears fleeing from their caves; or find bugbears shackled in the minotaur caverns; or just the minotaur and ogre huddling up in the minotaur’s cavern while they plot the glories of their revenge.

Let’s do it again:

1. DETERMINE FACTIONS: I roll 4 and 12. That’s Goblins and Wandering Adventurers.

2. DETERMINE OUTCOME: I roll a 5 for Both Factions Damaged.

3. INTERPRET RESULT: This one is pretty easy to figure out. A group of adventurers entered the goblin caverns, wreaked some havoc, and then got driven off.

4. GOBLIN ENCOUNTERS: There are 36 goblins total in this lair. A 25% loss would represent 9 goblins. I can represent this loss pretty easily be eliminating the wandering patrol of 6 goblins (the surviving goblins have bunkered down) and the 4 goblins guarding the store room.

5. ADVENTURERS: Where’d they go? Well, let’s say it was a party of 4 adventurers. One of them is dead and his corpse can be seen on a spike outside the goblins’ lair. The rest are either (a) camping nearby and looking for allies; (b) sold to the hobgoblin slavers; or (c) both.

FINAL THOUGHTS

It should be pretty easy to see how this simple system can be used to add a little quick spice to the complex between PC visitations. Combined with the ability to simply use some generic wandering monster tables to rapidly determine the new inhabitants of any lair complex emptied out by the PCs, it’s pretty easy to see how the Caves of Chaos could be easily used pretty much endlessly for low-level adventuring.

Go to Part 1

DELVE FIVE

The first four passes through this section of the dungeon had completely cleared out the anubian outposts on Level 1 and heavily decimated their forces on Level 2. I made the decision to allow this section of the dungeon to be temporarily cleared and dropped the chance of random encounters to one check per three turns.

This allowed the next group to pass through relatively quickly through largely abandoned chambers. They were once again tempted by the plaster-chipped door, but decided to pass it by when one of their veteran party members explained what the inscription said. Passing down to area 42 they encountered an ochre jelly (random encounter) who had taken up residence in the rubble pile and grown to a rather impressive size as a result of feasting on the dead rat corpses left behind by the last expedition. (This encounter nearly resulted in intra-party homicide when a particularly dim-witted knight couldn’t figure out that he was not helping matters by constantly hitting the ochre jelly and splitting it into smaller-yet-equally-vicious portions.)

They then continued south of this area, had several other adventures beyond the scope of this section (including rescuing an amazon warrior who had been frozen in ice for a thousand years), and then left.

(Nothing too exciting about this. If there is a lesson to be learned, it’s that you don’t have to cram in fresh content all the time. The importance of negative space — the absence of something to contrast its presence elsewhere — can’t be dismissed as a design principle.)

DELVE SIX

There was then a lengthy break in the campaign, which was marked in the game world by the pollen monsoon. When the PCs were able to return to the Thracian ruins, I spontaneously decided that an elementalist had moved into this vacated upper level. Accompanying him would be a number of lesser elementals.

And then, when the PCs kicked down the door to area 5, I found myself saying, “… sheets of malevolent flame dance around hearts of molten magma.” When the elementals died, they left behind smoldering, blackened pyrites. If they were struck with cold-based spells, I decided there would be a percentile chance that their magma hearts would explode from the sudden contraction (killing the elementals, but peppering the room with shrapnel).

So, those were pretty cool.

I also knew at this point that the anubians had re-fortified the guardpost in area 43, but the PCs didn’t make it that far during this session.

(This is our first major re-population of a deserted section of the dungeon. Couple things to note: First, I didn’t consult any repopulation tables. Why? Because I was struck by a cool idea. Random tables are tools, but I feel that you shouldn’t feel enslaved by their results.

Second, I’m not spending any time outside of the game prepping this repopulation. At the beginning of a session, I’m jotting down a few notes on how the dungeon has changed during the same time that the players are rolling up new characters, shopping for supplies, and the like. Of course, nothing says you can’t spend some time doing detailed prep work between sessions. But preserving the “I can play this any time” nature of your megadungeon means that you never want to feel like you need to do that kind of prep work before you can play the next session.)

DELVE SEVEN

When the PCs next returned to this section of the dungeon, I decided that the elementalist had been killed. (They discovered his flame-scorched body jamming the door to area 5 shut.) The reasons for this aren’t really important (and would be spoilers for my players), but this meant this section of the dungeon (along with 3 others) were depopulated.

I decided arbitrarily to check repopulation for each section by making a single 1-in-10 wandering monster check for each “section”. (The determination of “section” was essentially arbitrary on my part.) The check in this section came up positive, and I rolled on the Level Two wandering monster table (on the theory that some group from deeper in the dungeon had moved up to occupy these chambers).

The result was “giant spider”. There’s a minor spoiler here that I’m going to put into black text. My players shouldn’t highlight it, but the rest of you can do so to read it:

(On the second level of the dungeon there is a Shelob-sized spider that is described as having an egg sack of young spiders that’s ready to hatch. I decided that the egg sack had hatched, and some of the young spiders had migrated to this upper level.)

In any case, I decided these giant spiders had moved into the bat chambers. They had strung their webs and were basically feasting on the bats (whose population had been significantly depleted).

The PCs’ first inkling that something was wrong came when they found the giant spiderweb draped across the staircase leading down to area 2. After they had cleared out the spiders, they found the elementalist’s scorched body, verified that the rest of this section was still deserted, and then moved down to the second level where they engaged in multiple, semi-futile skirmishes with the anubian guardpost (which I had repopulated before the previous session).

(Here we can see how random tables can provide the raw seeds that you can riff off of to develop the megadungeon in interesting ways. This kind of improvisational extrapolation from a simple table entry of “giant spiders” is what makes the campaign come alive.

The wandering monster table is like the audience members who yell out suggestions on an improv show: Simply yelling out “mime” and “airplane” doesn’t make for a comedy show; it requires the improv actors to create a sketch about a mime pilot making an announcement over the plane’s intercom system for that. Similarly, just having random “giant spiders” attack the PCs because the table says so doesn’t make for an adventure; what you need are giant spiders in a particular place for a particular reason and doing a particular thing.

Why use the table at all? For the same reason the improv actors use audience suggestions: It keeps you fresh. It forces you to think outside of your comfort zone. It can give you an idea where you’re drawing a blank. Perhaps most importantly, it’s fun.)

A FEW FINAL THOUGHTS

At several points during the writing of this essay I found myself thinking, “This is really boring. This is just me giving a litany of fairly simplistic events.”

But maybe that’s the point: There really isn’t any magic here. You keep the dungeon alive by using wandering monster encounters to simulate the activity of the complex. You partially repopulate the dungeon inbetween sessions to keep it fresh. The result is that you can take 10 encounter areas, a couple of tables, and get dozens of hours of play out of it.

With that being said, if these 10 areas were the only section of the dungeon available none of this would work. First, the PCs would be able to “clear” the dungeon and there would be no immediate motivation to return. I could, obviously, repopulate such a dungeon and remotivate them to come back (“the draconian scouts have established their advance base in the same abandoned mines used by the orcish raiders!”), but there would be a greatly reduced sense of building on past successes or contributing to a single, larger goal.

Second, in the megadungeon the PCs aren’t being forced to go back over the same ground. They’re choosing to come to this entrance of the dungeon instead of another. This is important for both tactical and psychological reasons.

But, laying those caveats aside, my biggest point here is the ability to effectively reuse and refresh the megadungeon. This material can be used and re-used many times over without becoming stale. And if it ever starts to become stale, it’s a relatively trivial matter to freshen it back up again: Lizardmen invade the complex from the nearby swamplands. In a mighty, magical earthquake a new ziggurat pushes its way out of the earth leading to an entirely new complex connected in yet unknown ways to the caverns beneath. The black-eyed cultists approach some of the heroes to form an alliance against the aggressive anubians. And so forth.

In many ways, I feel like a megadungeon becomes the DM’s character. And I play my megadungeon much like I would play a PC. Before play begins, I don’t really know what my megadungeon is going to do: But my random encounter tables generate 2d4 anubians just after the PCs raid the depths, and I know the anubians have sent a team of assassins to hunt them down. Black-eyed cultists are holding a ritual on Level 2 and I suddenly know the sin day they’re celebrating. Lizardmen show up in the anubian sections of the dungeon and I know tensions are erupting between their tribes. Then the minotaur shows up to determine why tribute is not being paid and… and… and…

And a story gets told.

Go to Part 3: The Players Take Charge

REFERENCE MAP – PLAYERS DO NOT LOOK!

The rest of you may want to open that up in a separate tab or window.

An effective megadungeon has three basic components:

1. A map.

2. A starting map key.

3. Wandering monster tables.

The map should be large and thoroughly xandered. Xandering is crucial in a campaign megadungeon because of the complex and dynamic environment it provides: Players need to be free to choose different experiences each time they return to the dungeon. If you force them to trudge down the exact same path each time, the dungeon will have no effective replay value.

The map key should be flavorful and interesting. It will be frequently rewritten, but the starting key should provide a strong foundation for you to build on and a rich soil in which the dungeon can grow. Most old school bloggers I’ve seen tend to advocate minimalistic keys that tend to de-emphasize memorable geography. (For example, the Castle of the Mad Archmage contains key entries like “ORC SERGEANT. (8 h.p.) armed with sword and flail. He has 12 e.p.” and “SECRET CHAMBER. Great skeleton (3 HD, 15 h.p., turns as a ghoul, otherwise as a normal skeleton). Small locked chest holds 75 g.p.”) But I disagree with this approach: The monsters in the dungeon are ephermeral. It’s the geography that’s going to stick around. Minimalist keys are fine, but use them to make memorable locales. (Check out my Halls of the Mad Mage for my own efforts to use a minimalistic key to create interesting locations.)

Wandering monster tables have generally gotten a bad rap in many modern gaming circles. They’re generally considered to be “wasted time”. But when properly employed, wandering monster tables are improv tools and low-tech procedural content generators. (See Breathing Life Into the Wandering Monster for a deeper look at how this works in practice.) Wandering monsters also play an important part in maintaining proper pacing throughout the dungeon complex and help to make the complex “come alive”. In all of these functions, wandering monster tables are playing a vital role in preventing the megadungeon from becoming a place that can be “cleared out”.

Caverns of Thracia, of course, provides all three of these essential elements: Although the reference map I’m using for this essay shows only the small, specific section of the dungeon complex I’ll be discussing in detail, there are, for example, three completely separate entrances into the caverns and the delves described below represent only a fraction of the sessions I’ve run there. Similarly, Jennell Jaquays’ map key positively drips with detail — the unique characters of the Caverns of Thracia seem to ooze out of every room description. Jaquays also provides detailed and dynamic wandering monster tables.

THE FOUNDATION

Let’s start with the basics. Looking at our reference map, allow me to present a very simplified/summarized version of the pertinent map key:

1. Walls once painted in brightly color murals. Now home to several hundred bats. The floor is covered a couple feet deep in bat guano.
2. Columned hall. More bats and guano.
3. Ruined statue, digging rubble pile turns up the face of Athena. More bats.
4. Ruined statue of a winged figure. Giant centipedes (x19).
5. Ruined statues reduced to complete rubble. Lizardmen hunting party (x4).
6. Spear trap.
7. Anubian Guardpost. (x6)
8. Sloping passage.

42. Rubble-filled cavern. Colony of rats in rubble (raise alarm if disturbed).
43. Guardpost and Pit Traps. Anubians (x4). One of the pits leads to a sub-level with a small, hibernating dragon.

In addition, the module provides two wandering monster tables — one for Level One and one for Level Two. There is a 1 in 10 chance per turn of generating an encounter.

Simple enough, right?

Now, let me show you how I’ve used these simple tools to run 20-30 hours of high quality gaming.

DELVE ONE and DELVE TWO

The first delve is pretty simple and by the book: The PCs entered the dungeon, held their noses at wading through bat dung as they headed through areas 1-3. They found the lizardmen in area 5 who were nursing a comrade who had been injured by the centipedes in area 4 (as described in the adventure key). They killed the lizardmen and then entered area 4 to fight the centipedes themselves. After a nasty fight, they spiked the door shut, dragged the corpses of the centipedes that they had killed out of the dungeon, and returned to the jungle. That night they feasted that night on roasted centipede meat.

When they returned to the dungeon the next day I generated a surface encounter using the Level One wandering monster tables. It turned out to be a rather tough one, featuring a minotaur along with half a dozen dog-faced anubians. What were they doing there? Guarding the entrance. The party’s wizard tried to use a sleep spell, but it failed spectacularly. He ran back to where the others were waiting, but they all dithered long enough for the minotaur to reach them and then it turned rather abruptly into a TPK.

The heads of the PCs were placed on pikes outside the dungeon entrance (where they remain to this day).

DELVE THREE

The players rolled up new characters and ended up entering the dungeon through a different entrance. A few sessions later, however, a different set of PCs returned to this area. They discovered a half dozen anubians (minus the minotaur) standing guard at the entrance. (Another random encounter, which also slotted naturally into the “guarding this entrance” concept.) This time the battle went much better for the heroes and they were able to clear away the freshly positioned guards.

Downstairs they returned to area 3. They could hear noises coming from behind the door to area 5 and saw that the door to area 4 had been spiked shut. They tried to ambush the anubians in area 5 (which had been generated from the wandering monster tables), but the door squeaked when they tried to open it and the anubians were warned. Despite this, they dispatched the anubians.

With their backs secure, they carefully pried up the spikes. Somebody scooped up some bat guano in a skull and tried to use it to grease the hinges and then they threw open the door.

Angry red centipedes looked up at them.

They slammed the door shut and spiked it again.

Exploring the room where the anubians had been, they found the secret door. They turned left, through area 8, and down to the second level.  They fought some giant rats in area 42, spotted the guards in area 43, and decided to retreat back to the first level and finish it off.

There they fought and killed the anubians in area 7, looted the treasure chest, spiked the door shut from the inside, and spent the night. In the morning there was a loud buzzing coming from outside the door, which turned out to be stirges which were feeding on the corpses they had left outside the door the night before. (The stirges were a wandering encounter; I figured feasting on corpses made the most sense given the circumstances.)

DELVE FOUR

The PC who had been mapping in the previous delve sold their maps to a newly formed adventuring party for a percentage of the treasure liberated on their expedition. (The player of the PC who owned the maps couldn’t play that night.)

This group returned to the tunnels and finished exploring this section of the first level. An elf in the party detected the secret door hidden behind some plaster at area 9A, but when they discovered that the inscription on the door read: “KNOW YE THAT BEYOND THIS PORTAL LIES THE DEMESNE OF THANATOS, THE CURSED, HATER OF LIFE, GOD OF DEATH. SEEK NOT TO PASS THIS GATE FOR IT LEADS ONLY TO HIS BOSOM.” They decided that discretion was the better part of valor and left it alone.

But what the party was really here for was to push through the guard outpost on Level 2. Down they went and got into a huge melee with the anubians. (Complicated by a wandering monster encounter that reinforced the guard post.) During the fight, one of the PCs fell down one of the pits depicted on the map… which led to a chamber where a small dragon was hibernating. (This was all according to the map key.)

There was some abrupt panic, but the PCs rallied and actually managed to kill the dragon. (They were very excited about that.) In the pit they found several ancient Thracian artifacts, which they hauled back to town and sold for a tidy profit. (It was at this point that Himbob Jimblejack bought up all the garlic futures in town and set up his monopoly on garlic sales.)

FIRST DESIGN INTERLUDE

Up until this point, things may seem fairly standard. I haven’t really deviated from or supplemented the original dungeon key. But the one key factor to note here is the effect that random encounters have had on the game. Half of the combat encounters have been with randomly generated encounters:

KEYED ENCOUNTERS

• Lizardmen (Area 5)
• Centipedes (Area 4)
• Anubian Guardpost (Area 7)
• Lower Anubian Guardpost (Area 43)
• Dragon (Area 43)

GENERATED ENCOUNTERS

• Minotaurs + Anubian Guards (Delve 2)
• Anubian Guards (Delve 3)
• Anubian Guards in Area 5 (Delve 3)
• Giant Rats (Delve 3)
• Stirges (Delve 3)

At this point, these generated encounters have accomplished three things.

First, they have slowed the pace of the PCs exploring the dungeon. By providing an additional ablative layer, they have prevented the PCs from delving as far into the dungeon as they otherwise would have been able to. This puts a premium on exploration — their knowledge of the deeper complex is hard-earned and, thus, more appreciated. (Of course, this also presumes that there are interesting and cool things to find down there in the first place. Fortunately, the Caverns of Thracia provide that.)

Second, they prevent a “return to save point” mentality. You can’t just leave the dungeon, come back at a later date, and pick up where you left off. Permanently clearing a section of the dungeon is hard work, and it’s not particularly permanent. (There are not guarantees that something won’t wander back in or that deeper denizens won’t extend their guard perimeter.) This provides a drive to “push on a little farther” because they know that they’ll have to fight hard just to get back to where they are now.

Third, they are keeping this section of the dungeon fresh. In many ways, it really is a completely new dungeon crawl every time they go in. But, on the other hand, their preexisting knowledge of the geography of the place is a reward in itself. (“Oh, I know how to get past these guys. There’s a secret passage a couple chambers to the west that we can use to bypass them.”) That this knowledge is valuable to them is proven by the fact that they were willing to pay cold, hard cash for it.

Tomorrow we’ll take a look at the next step in managing your megadungeon…

Go to Part 2