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Worlds of Design: Making Megadungeons Make Sense

When D&D originally came out Gary Gygax more or less taught GMs that they should make huge multilevel dungeons that the adventuring party would enter and loot, killing the monsters who were guarding it. But in my case we were eager to play, so as GM I made what gradually became a big, sprawling, somewhat random dungeon. And it didn’t always make sense.


My dungeon was only six levels, and the levels were not the vast kinds of things we see in true “Megadungeons” where the graph paper map for one level could be as much as a yard by a yard. Quite apart from the huge question of why does the place exist, we had monsters living adjacent to each other who should be hostile but seemingly didn’t know the others exist, monsters living in places without ventilation, sanitation, or access to food. Inexplicable magics like Gary’s fountain of kobolds (IIRC), a continuous upwelling of kobolds in the middle of a room: where did those kobolds go, let alone where did they come from? One-way doors, secret doors, and rotating rooms placed mostly at random. We didn’t care, it was fantasy, it was a game. And it gave us a sense of wonder or of mystery, a sense of the fantastic.

There was a reason we created dungeons this way. The fundamentally nonsensical dungeon was practical to reduce the work required of a GM. (Keep in mind, there were very few commercial adventure modules at that time, everyone had to make up their own stuff.) I don’t think anyone can argue with that. Gygax's solution to the difficulty of worldbuilding (as paraphrased from Jeffro Johnson, author of Appendix N: The Literary History of Dungeons & Dragons, on Twitter) was to:
  • Have lots of space.
  • Place lairs with vast quantities of loot
  • Use random encounters to simulate an active, dynamic environment with very little effort.
But there’s an entirely different way of making dungeons that makes much more sense, though it takes more time.

Gritty Realism?

When I play RPGs now, I like to feel as though it should make some sense, something like Glenn Cook’s the Black Company, a kind of gritty realism rather than wild (Dunsanian?) fantasy. To me the vast dungeon with unrelated contents and inhabitants, often no way they could even get in and out without running into others, no way to get air, no way to get food, is just plain nonsense. It breaks the immersion in the world that many gamers look for. Worse, there is no explanation for why this vast dungeon exists. I don’t buy for a second the “mad wizard created it” excuse.

So after my initial six level dungeon made primarily for my brother in the Gygaxian Megadungeon style, I kept my underground designs to individual lairs or to Skystone Castle and its environs.

Skystone Castle

Skystone Castle grew out of my thinking about how magic would modify military considerations (keeping in mind I have a PhD in military and diplomatic history, and when I first played D&D I was already two years into graduate school). In an environment where fireballs and lightning bolts are somewhat plentiful, where a charmed umber hulk or burrowing monster can dig underground and undermine any wall, a fortification in a magical world would look more like the World War II Maginot Line than like a medieval castle, with most of the fortifications and living spaces underground. Skystone Castle was an abandoned very large fortification built into an enormous rock that grew out of a featureless plain, and allegedly had fallen from the sky. Such rocks exist (though not from the sky), for example Traprain Law in the UK (though I think of it more as stone than as a hill).

The fortress was long abandoned. Creatures had moved in and made modifications. But I experimented with actually having creatures move in and settle down, as governed to a considerable extent by dice rolls. Sometimes those creatures could burrow or mine-out additional areas, and the map changed accordingly. Sometimes those creatures might live in the dungeon a long time and then someone else would move in and chase them off or slaughter them. Sometimes evidence of inhabitants (and battles) long past would remain behind.

This all made changes in the dungeon. It was like a game in itself, seeing what would happen, and of course I had ideas about what I wanted in the dungeon and that governed who turned up and how strong they were. The result was a “living dungeon” rather than a caricature.

I accepted the notion that the more powerful monsters would tend to want to live deeper, in order to retain the game-practical idea that the deeper you went, the more dangerous it became. Though in smaller such places the danger level was roughly the same regardless of where you were in the “dungeon.”

A Question of Immersion

I still use this method between adventures, so that sometimes when the party comes back to the dungeon it has changed in some ways, if only in the inhabitants, which I think makes for a much more interesting place to adventure in. “Clearing out” a dungeon and never having anyone fill in the space, as in the old Gygaxian dungeons, doesn’t make sense. Yes, it takes more time, but it’s a lot more interesting.

This is not a question of somehow improving sales, it’s a question of improving the immersion that is necessary for most any game. Wild fantasy is one thing; something more realistic, whether it’s the Glenn Cook’s-style of realism or the Tolkien-style of realism, is just as valid a way of playing RPGs in general and Dungeons & Dragons in particular.

My question to readers, then, is what kind of dungeons (if any) do you have in your campaign, and why?
Lewis Pulsipher


Eyes of Nine

Everything's Fine
So first of all, I am reminded of "How to Host a Dungeon" when it comes to generating the history of a dungeon area. Great lonely fun, and result is very similar to what you wrote about.

I am also now desiring a treatise/blog series/mini-book about how society in general and military strategy would change in a pseudo-medieval setting if there was relatively easy access to the magic posited in D&D. If it was done by someone with a PHD in military history or sociology or anthropology, well all the better...

Hmmm, wonder if there's anyone who might have those qualifications...?


My dungeons tend to smaller with only 5-15 rooms and have only a few encounter areas. Most are tombs or natural caves where smaller rooms make for one encounter and monsters join combat each round as they pour out of more rooms. I like to have a set dungeon that I them modify to age them. I recall somewhere where a fissure opened in one of the DM help articles some years ago and I have included that trick a few times. Some others may be an ooze lair having holes in the ceiling/floor to another level where you could bypass the planned stairs. If I needed a massive dungeon I would buy one of the Undermountain or Rappum Amuk (sp) and modify it.


Small God of the Dozens
I tend to smaller dungeons. Something that can make some sense as a unit. You can certainly overdo the history bit, but I do like to include some hints that the location has had other inhabitants and seen use over time. An abandoned observatory in the forest, dilapidated keeps and towers, that sort of thing. Mostly they're done in a session. If I want multiple sessions I'm more likely to spread it over multiple smaller locations than to design something huge.


Title? I don't need no stinkin' title.
I think the last mega dungeon I did was when I was a teenager. The hallways of each level spelled a word and, of course the lowest level was the most dangerous.

So the layers in order spelled out "Death", "Doom" and "Destruction". No logic, no reason. Just a bunch of monsters with a dragon on the lowest level and a plaque dedicated to the creator of the dungeon.

I wrote something along the lines of "Uno de podero vivir!" on a 3X5 card. Then I handed the card to the player when they asked what the plaque said. They read it out loud which of course brought the all powerful lich back to life. High school spanish class actually paid off.


I went for the giant megadungeon back in the day. It's still in use :) I did come up with basic reasons for its' existence and I spread it into numerous smaller parts. It's a huge underground fortification (the above ground part is mostly gone) dating from a series of ancient wars. Well stocked with magical affects / defenses, undead, miscellaneous dungeon flora / fauna, and various invaders and adventurers. It consists of dozens of linked dungeons with various themes. I still use the "deeper is deadlier" trope. Some areas are relatively small, others are gigantic. Various parts range from level 1-5 to levels 6-12. Essentially there are watchtowers, barracks, armories, mines, magical workshops, palaces, etc. There are various underground routes connecting it all up; tunnel / foot roads (with gated watch posts along them), "highways" populated by stone golem "trucks", underground canals and rivers, teleportals, magical gates leading to other locations... with the caverns of the Land Beneath the Land Above under that (this being an underground outdoor adventure). There are various vast architectural features / defenses as well. Given the history of the setting it makes reasonable sense. And, it's fun :D

There are, of course, numerous smaller locales scattered around as well that aren't part of a larger whole.

Which sounds a lot like Skystone Castle. In a fit of less than original thought I call mine the Hollow Hills for the ruined above ground remains that resemble a large set of hills.
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Never did design a megadungeon. I think my only attempt was a 2-3 level affairs heavily influenced by the caves of chaos with a community of dwarves defending their hard one territory from the various other humanoid communities.

However my own dungeons were always heavily influenced by 2-3 dungeon design/ecology articles Lewis wrote in White Dwarf in the early 80s. I no longer have the mags but the aricles are in one of my early dming folders somewhere.


I generally hew to small to medium sizes, since I fashion my own. I've run official ones, like Ruins of Undermountain (2e), but generally find them unsatisfying (mainly because I can never remember all the details and have to refer to the books often...which tends to derail the momentum my players build exploring). When I create them myself (and keep them small to medium), I tend to remember them in greater detail, which my players have responded very well to. I also try to keep the layout and organization to something sensible (for a constructed dungeon) rather than just randomly populated with nasty things (though for more natural dungeons, like caves and tunnel systems, it tends to be more random, but with occupants that make sense).

Leafing through a friend's copy of Descent into Avernus, I got an idea to do something with Fort Morninglord (going to be known as 'Hellhall' in my game). Basically 10 levels with the above ground level 'safe' but populated with clues and things that brought down the once great fort...with each descending level a sort of a broken off piece of the Nine Hells of the appropriate type (so Avernus, then Dis, then Minauros, etc down to Nessus). Just have the basic concept for now, but plan to flesh it out, add some narrative to my existing game and see how it goes.


Victoria Rules
Probably the biggest dungeon-like complex I've run all the way through is Dark Tower.

I tried running Temple of Elemental Evil once; they cleared the top level and about half the next one, went back to town to train and regroup, and then between one mishap and another never got back to it to finish.

As for my homebrews, I've come up with lots of dungeon-like adventures over the years but most aren't all that big - 20-40 encounter areas, maybe, over two or three levels. I've once or twice kinda waved at doing something much bigger but never really got very far with anything.

I did do one quite gonzo one that was bigger - something like 70-ish encounter areas - where I was very intentionally trying to capture that feel of monsters not belonging where they were (and not being able to fit through the doors) and things generally not making sense: an homage to Judges' Guild's Sword of Hope that I called Shield of Faith (a.k.a. Danger Hill). I'd release it on the unsuspecting world - it's in finished-ish printable form, absent some editing - except it swipes too many identifyable bits of IP from too many other sources and I'd probably never get all the required permissions.

There was even a sort-of rationale for how and why the various monsters came to be where they were and why-how they hadn't yet died of starvation or thirst. :)

My biggest mega dungeon burned if a firehouse. It was the ruins of an ancient city that was built upon an even more ancient city which was built upon... well you get the picture. Most encounters in the begining levels were with humanoids, traps, hazards and a few undead here and there. Then there was thematic and semi-thematic levels. One would be with a wizard and its minions, and other was a dragon trapped in there because greed kept him in the dungeon (players had had encounters with the dragon's minions carrying dirt and soil to the surface because the dragon was making them dig for the surface). Even then, I was 13 and I was trying to bring some logic. The deepest dungeons were filled with undead, constructs and outer planar creatures.

But my best mega dungeon, which burned too, was the Labyrinth. It was set in a city, and it was a contest. Each year, 4 groups were to enter the labyrinth, fight each other and the menaces that could be found in it, to bring back the Orb of the Vanquishers! The prize? A wish for all party members that survived. Those who died or failed to come back before the 7 days period, were raised from the dead and were forced to serve the Archmage Ozzymandius for five years. Sometimes it meant geas and quests for the Archmage, other times it meant being a foe for the contestant in the labyrinth. It was a dungeon with 12 levels and the few groups that tried it found it challenging and fun. God I wish this fire didn't happened.


Currently designing my 2nd megadungeon as an adult DM. I start with the fantastic weirdness and work backward rationalizing that weirdness. This inevitably adds more weirdness but all with a discoverable method to the madness.

My key innovation in this iteration is relating factions and goals within the megadungeon/underworld to factions and goals in the city above. The different groups that will be faced with this adventuring environment will have their choices of what kind of session they want - whether it is murder hoboing or intrigue.


My question to readers, then, is what kind of dungeons (if any) do you have in your campaign, and why?
It really depends on where the dungeon is and what’s going on with it. Usually, there should be something that makes sense about it and a reason why it’s there.

I like to do the dynamic stuff that’s written in this article. It really helps create an opportunity cost for resting when the dungeon is dynamic and changing, especially players start worrying that something is going to move into the dungeon and while they’re away.

I run an exploration-based game, so I’m a big fan of Jaquaying my dungeons. When there are multiple paths through a dungeon, and you can’t count on one way remaining safe, finding shortcuts and alternate routes start to become actually important.

My PCs have recently started exploring an actual megadungeon, which is my first one. One of the things about this campaign is there’s exploring a region that was devastated long ago in the War of the Giants. No one can really remember what happened, but they know it was bad. I know that (among other things), it caused significant damage to time and space in the region. This lead me to my first idea: they’d start exploring a cave then emerge onto a bridge between motes in the sky, and there would be a mansion they could see above them on top of one of the motes.

Designing the dungeon itself has taken some learning. At first, I just knocked out a map. I had several floors, including several sub-levels on the 2nd floor. The problem is trying to key it just got too difficult because nothing was contextualized. After sitting down and doing a stream-of-concious brain dump, I am now in a much better position. I figured out who lives there, who uses the dungeon, what everyone thinks of each other, how they are able to survive, the relationships, and so on.

I feel like having factions is an important distinction between a regular dungeon and a megadungeon. This opens up opportunities for the PCs to play the monsters against each other, and it also brings them up closer to parity with those living outside the dungeon. I’m really looking forward to when my PCs finally starting meeting the ones I’ve put together to see which ones they befriend and how they react to the antagonism between them.

Oh, and I have an entire floor inhabited only by mimics. I mean, why not? I think it’ll be amusing making my PCs develop a paranoia about whether their treasure will attack them. 😈

Von Ether

My favorite mega dungeons to design are abandoned cities. Plenty of room and houses become micro dungeons in the bigger dungeon. Also different quarters can have different themes and factions. If you are worried about people "leaving" the map, put them on islands or in canyons.


I ADORE mega-dungeons. I really do.

One of my proudest times DMing was AEG's The World's Largest Dungeon. Had a FANTASTIC time.

Y'know, thinking about it, @lewpuls notion of starting with a dungeon seed and then running a sort of quasi-sims program where successive waves of inhabitants rule, govern and expand the dungeon, would be an absolutely freaking fantastic dungeon generator program. Imagine if you could start with a small seed map, add in a few parameters, and then "grow" your dungeon until you reached a point where you were happy, and then the program would spit out a pdf with your dungeon all done for you. Or, even better, a Fantasy Grounds .mod. :salivate:

That would be fantastically cool. Someone must have done this already.

Megadungeons are very cool and so much fun if done well. Unfortunately, I think some people really get turned off of them after a poor experience or two. There's a lot to running a successful megadungeon. Here are some starting hints:

1. Set goals and make the goals achievable in a reasonable amount of time.
2. Randomly wandering a dungeon is fun for about ten minutes. Then it just becomes a grind.
3. Give information to the players. ALL THE TIME. Drop maps, have prisoners tell about areas ahead, drop clues (whether tracks or actual droppings :D) See #2
4. Add verticality. One problem in a lot of megadungeons is each level is a perfectly flat plane. That's BORING. Up slopes, down slopes, ledges, exits from a room that are fifteen feet off the floor, all add variety and interest.
5. Place encounters in corridors from time to time. If every encounter only occurs in a room, then corridors get boring and pointless. Why bother sneaking and being tactical to flesh out the map, eating up all this table time, when there are no actual encounters in the corridors. Just unfog the corridors and move on.
6. Add bits and bobs to rooms. The World's Largest Dungeon had an excellent list of about thirty different room effects, all labeled. So, maybe this room is a bit colder or warmer or that room is noisy or quiet or smells good or bad. Whatever. Again, variety is key here.

I'm sure others could add more.

John R Davis

Article is interesting but nothing new. In a time of air power and magic artillery castles become redundant, hence the dungeon makes a lot of sense.
Like my dungeons to only have about 12 rooms per level, but with Jaquays ups and down. I despise empty rooms. Everything should have a little something, even if it's a discarded thing or clue to the past. I put a lot of secondary story telling in my published dungeons ( the PCs will rarely be the first heroes to tread it's dim lit paths).

Ive run games in Undermountain since the first boxed set. I break it up into smaller sections and limit the options for my players otherwise the potential of giving them too many choices Im not prepared for is too great. Not to mention theres so much un-detailed areas or the areas that are detailed the entry is ridiculously long. I usually just make up my own stuff which is pretty much what you end up having to do anyway. Running it as written is just more prep than Im willing to do.


A Title Much Cooler Than Anything on the Old Site
Back in the 80s I didn't run many mega dungeons. I liked more sprawling stories, often with a lot of wilderness travel (something that is much less part of my current campaigns).

When I did make dungeons, I tried to make them make sense to some degree. A good resource for this style of dungeon design from that period is "Central Casting: Dungeons" by Task Force Games (from 1991).

But now, I'm more happy with "an evil wizard did it".

I've been running Rappan Athuk over the past year and I love to take any opportunity to share one of my favorite quotes from a gaming book's forward:

Once upon a time, there was an idea — an idea formulated by Gary Gygax and Dave Arneson who got together in 1974 and published in a little paperback book set (maybe you’re heard of it?), including a little tome called Underworld Adventures. The idea was simple: it is a lot of fun to go into a dungeon and kill evil monsters. Why is the dungeon there? No one knows. Why do the monsters usually fight rather than talk? We aren’t really sure. Why are there 16 trolls in a cave with a jug of alchemy? No one cares. What do all the monsters eat? We don’t know that either (although “adventurer” probably tops the list). And we don’t have to know these things. This isn’t an ecology experiment, it’s a dungeon — the quintessential setting for pure swords and sorcery adventuring.

I'm quite happy with this style of play. No more happy, I still like more modern styles of play as well, but I don't have to throw out my beloved dungeon crawls. I can enjoy both. Personally, I think that even the most realistic or at least logically consistent campaign should have at least one WTF fun-house dungeon thrown in without any explanation.