WHY MEGADUNGEONS? A Campaign Structure for Modern Lives

 

Original image from the Diablo pitch document, which now
feels like an OSR doc from yesteryear

Why Megadungeons?

Over on the Prismatic Wasteland Discord, a member asked essentially, "Why megadungeons?" This is a good perennial question that deserves perennially blogged answers. Heck, Ben L. of Through Ultan's Door does a whole podcast on the who, what, when, why, and how of megadungeons- Into The Megadungeon. Go listen, its a treat! The questions deserve continual attention because megadungeons are a foundational campaign structure for Dungeons & Dragons and, therefore, the campaign structure of most descendant fantasy adventure games. 

Dave Arneson's Blackmoor campaign, the genesis of D&D as we know it, quickly became centered around the group’s individual characters repeatedly delving into the dungeon below Castle Blackmoor. While it was not initially intended to be this way, accounts suggest that the dungeon delving proved so enthralling that the player refused to abandon it. Only after losing Castle Blackmoor itself, did the players tear their attention away.

A while later, once Gary Gygax was introduced to Arneson's novel campaign structure, he too began to formulate his own castle-based dungeon of infinite levels and the famous Greyhawk campaign begun. Its impact on D&D cannot be denied. But Greyhawk was not the second dungeon; one of Arneson's players created Castle Tonisborg with a soon-to-be-released early draft of D&D in 1973, which again featured many multiroom levels filled with treasures, traps, and several dragons.

This vast dungeon campaign structure also predominated outside of the D&D founder’s groups. If you read early editions of Lee Gold's Alarums & Excursions, early campaign structures often feature deep dungeons. And even one of the earliest published third-party modules for D&D by Judge’s Guild was the Caverns of Thracia (1979). A very excellent dungeon whose gold-standard design is covered here by Gus L. of All Dead Generations.

Megadungeons ARE D&D.

Megadungeons in Video Games & Popular Media

However, megadungeons are not relegated to the past nor to the gaming niche of pen and paper RPGs. Megadungeons have been a big component of early and current video games too! Early PC dungeon crawlers like Wizardry, which I cover here, featured multi-floor dungeons that had to be delved by the player's party and hand-mapped by the player themselves. Of course, Diablo represents another example of a very famous and beloved video game series that features a megadungeon structure (see the image at the top of the post).

Wizardry (left); Super Metroid (right)

Megadungeons as a game design structure gained significant attention with the release of Super Metroid (SNES, 1994) and Castlevania: Symphony of Night (PS, 1997), which eventually led to the genre-defining term "metroidvania". The recent metroidvania game Silksong, a sequel to the acclaimed Hollow Knight, has put megadungeons right back into the forefront of people's minds. I direct you to Josh at Rise Up Comus for a nice discussion about how metroidvanias convey their megadungeon structures in detail. But I think simply looking at the two maps below you can clearly see Hollow Knight owes a lot to the dungeons of Dungeons and Dragons.

Dungeon example from Holme's Basic D&D (left)
Map from Hollow Knight (right)

Finally, megadungeons are not just a setting for video games. There are a few examples of very popular media that also place their story in the context of a megadungeon. The first that jumps to mind is Dungeon Meshi, which bears a shocking resemblance to old-school Dungeons & Dragons, but less surprising once you realize one of its big influences is Wizardry. In the category of hot-at-Barnes-and-Nobels, the book series Dungeon Crawler Carl, amusingly abbreviated DCC, is also gaining steam as a popular book series featuring a megadungeon, and it looks like Seth McFarlane's company will produce it as a TV series. The plot is that an average Joe, Carl, is ensnared in an intergalactic TV show after all of Earth is turned into one giant multi-level dungeon. The series feels more like it takes after World of Warcraft than anything else, but it's still a vast dungeon and dungeon crawling at its center. New manga Tower Dungeon also features a band of heroes attempting to reach the top of a 100-level tower to rescue the princess from a necromancer.

Megadungeons ARE D&D, but not JUST D&D.

Misconceptions of Megadungeons

Hopefully, you are convinced by the above that megadungeons are not an archaic campaign structure but one that is alive and well in the public consciousness and, therefore, might be a great way to start your next or even your first Dungeons & Dragons campaign. And to help encourage that, let me take a stab at answering some of the misconceptions about megadungeons:

Dungeons are boring hack & slash: This can befall almost any RPG game. While dungeons are a basic unit of play in fantasy adventure games, they are not a simplistic unit of play. Dungeons are a creative environment for RPG because they allow a dungeon master and players to develop the call-and-response flow of table participation that is required to make most RPGs work.

Furthermore, good dungeons are choice-laden, but are more constrained than their wilderness or open-world counterparts. This often provides the need for improvisation, but limits the need of novelty to a set of recurring themes and subjects at any given point. This constraint prevents a new DM from having to narrate 3 different ongoing situations, likely when starting a campaign off in a town or wilderness and saying, “so what do you do?”.

I don’t have time to key 300+ rooms: If you are going to design one, how big does it have to be to be a “mega” dungeon? I tend to think there are two qualities of a megadungeon: (1) is a minimal size and (2) a functional component. First, in terms of size, Hole in the Oak, a popular starting dungeon, is about 60 keyed room. Caverns of Thracia, which is a highly lauded megadungeon, has only about 117 keyed rooms. While 2011’s Stonehell, another highly recommended megadungeon, is over 700 rooms. 

Second, “keyed rooms” might not be the best measure because 1 huge room could require as much table time as 5 smaller rooms. So, another definition which I think is probably more applicable to today’s entertainment-compeditive lives, is that a megadungeon is a dungeon that forms the loci of play for an ongoing campaign. This means the dungeon is the center of action, with other locations, e.g. “the town”, playing a supportive or peripheral basis mainly as a place to provide downtime actions between the dungeon crawling.

Also, you don’t have to key everything at once. Gygax recommended having about 3 floors ready to go before calling your group together for the first game. However, we aren’t playing 8-hour sessions, so even having 1 complete floor of 30-50 rooms keyed would be enough to get started.

Dungeon design is difficult because its hard to design good dungeons: You might say that dungeon design is already difficult, made more so by having to create over 100+ rooms interesting enough to support a campaign. Well, fortunately, the creator of His Magistry the Worm, Josh McCrowell and I have written a dungeon design document. This course walks the reader through the steps needed to create a solid, table-ready 30-room dungeon. One can easily replicate this process 3 or 4 times to yield a 90 to 120-room, multi-floor, megadungeon. A key points is one is aiming for playable dungeons, not dungeons so excellent they redefine the genre. Give yourself a break and aim for bored-in-class creativity! Here Nick discusses how to make a megadungeon in two weeks. Miranda of In Places Deep also has good advice.



100 rooms of the same theme will get repetitive: I can definitely answer “no”. Through my many, many years of playing just Dungeons & Dragons, I can say that I still get excited delving cursed crypts filled with the undead. Megadungeons are great at distilling ideas AND giving them depth. Each floor can be populated with only a few ideas, themes, or aesthetics. Which means you don’t have to have an entire list of complicated plots, plans, relationships, and NPCs before you begin to execute a whole campaign. Megadungeons are a canvas to iterate on those same things repeatedly, which allows you to fully draw out an element’s flavor, because you must variate on each element. The opposite side of the coin to dungeons is “wilderness hexcrawls” can be a load of fun and certainly has been popular in the “West Marches” format. However, I think hexcrawls can dilute ideas because a DM is required to spread them out over a much larger area, like a kingdom/region, and the basic unit is the 6-mile hex not a single room. Even with several items per hex, this can give the feel of a lot of empty space. The players also cover more ground and retrace less frequently. This further increases the need for novelty and decreases the impact of a single idea.

Moving through the same rooms will get boring: To address again the fear of repetition, megadungeons employ repetition simultaneously on two levels: in-game level and at a meta-level. For the former, the familiarity born from repetition allows the players to quickly navigate the megadungeon, exploit its secrets for their benefit, and maximize the impact of faction engagement. For the latter, repetition increases player knowledge of the fictional world. It helps cement the names of NPCs, location, and keeps them abreast of recurrent themes. Repetition also helps the DM ensure novelty has an impact. If a party has explored and passed by the fountain of Zeus 10 times, then they are going to be pretty surprised and intrigued when the fountain is cracked, water drained, and there is a staircase leading down into the dark.

Well, it is a silly idea that one person or group built some huge complex for no purpose other than to store their treasure: Another common complaint that I hear is that a megadungeon in too contrived even for a fantasy game with giant, fire-breathing lizards. That a wizard did it, is too insufficient or by the power of the mythic underworld is too handwavy. I only ask that one take a moment to look at how the mega-wealthy and powerful lived both in the past and present. For instance, the Palace at Versailles has 137 rooms listed which is more than the number of keyed rooms in Caverns of Thracia. The founder of Facebook is supposedly buying up eleven houses, which totals to something like $100 million on his block to create a complex in California. Even if that is not convincing enough, let me try this one last thing. In terms of fantasy adventure gaming, much like videogame counterparts, it is much more important to have a gamable space that aesthetically resembles a realistic space than it is to have a truly rationalized and functional area. After all, more real tombs are linear and contain few rooms at all.

Megadungeons are where the familiar allows expression of the fantastic.

Megadungeons as Campaign

Finally, I want to end by addressing the megadungeon as a campaign structure.

I think the modern play environment today is a far cry from Gygax’s weekly 8-hour gatherings. And instead, most people involved in D&D post-college can only spend about 2-4 hours per session, once a week. I know I am fortunate enough to play about twice a week, but anymore is really stretching it. It might seem contradictory, but this play constraint is very excellent for a megadungeon campaign.

Megadungeon have a simplified campaign structure/loop: Town to megadungeon and back again. The dungeon, of course, is where the action is and the town is where resupply is. But the town usually contains a civic faction, a religious faction, and 2-3 other groups that represent the world at large. Additionally, the proximity to a dungeon of legend provides a good reason for all sorts of weirdos to visit. And, of course, things in the dungeon could also crawl out of it. And, there is usually enough reason to have a few areas outside the town to also provide a small regional space: the other town that hates the dungeon town, the hermit’s hut, the strange standing stones, the lake, and the ruin temple/tower. All which can be their own adventure locals, other entrances to the dungeon, both, or just locations for extras like spell components or special training. When combined with repetition, this means in just a few 2-hour sessions, players become very familiar with a lot of their local world. This reduces the need for a DM to repeat names, locations, relationships, and lore because there is just not that much there to catalog, and the players see it a lot. A huge advantage!

On top of that, it also doesn’t take long for players to see the impact of their actions for good or bad. In a large hexcrawl, if you burn down the inn, players can just move on. In a very local megadungeon campaign, they are sleeping outside or in the dungeon. In a hexcrawl campaign, if the evil mimic leaves with the party, they might not see that effect for a while. However, in a megadungeon campaign, said mimic might become the favored inn, replacing (mysteriously overnight) the prior inn they burned down.

Megadungeons are where the familiar allows focus on play and player actions.

The End, but the Beginning

…of your megadungeon campaign!

I’ve hoped I’ve been able to to convince you that a megadungeon is a contained campaign space that concentrates fantastical ideas by stretching them to full effect, uses repetition to the player’s advantage, which enhances play investment, increases the impact of novelty and change in the adventure location, while being a format that combines well with busy adult lives. And instead of being a campaign of the yesteryears of Dungeons and Dragons, it is a campaign structure that is being brought back to gaming consciousness through manga like Dungeon Meshi or Tower Dungeon and through video games “metroidvania” genre like Hollow Knight/Silk Song and Blasphemous 1 & 2.

Appendix L(IGHT): Vanitas, Lightly Annotated Later

Allegory of Charles I of England and Henrietta of France in a Vanitas Still Life
Anonymous Flemish painter, 1670s.


It was interesting to reflect on images and aesthetics that permeated my mind when thinking about the type of fantasy adventures I am drawn to or try to replicate. 

Here are some media that might have been responsible. I wanted to annotate it, maybe later, or perhaps better without comment?

Aeon Flux

The Maxx

Go-Go the Dodo

Farscape

LEXX

Perdido Street Station

The Windup Girl

Saga

Ghost in the Shell

The Bloody Chamber

Black Tongue Thief

The Bloody Chamber

The Magicians

Elric

Farfad & Greymouser

X-men

Salvador Dali

H.G. Giger

Black Moth

Tarot Decks

Bulfinch's Mythology

Clash of the Titans

Lost in Space

Muppet Show

Jim Henson's Storyteller Series

East of the Sun, West of the Moon

Between Two Fires

Legend of Zelda (NES)

Dragon Warrior (NES)

Final Fantasy (NES)

Vermis I & II

Millenium

X Files

Peter Paul Rubens

Vanitas paintings

Darwin's Finches

Early OSR 'Zines

Moebius

Swamp Thing

Dungeon Meshi

Tower Dungeon

Dorohedoro

Sledgehammer Music Video

Don't Worry Be Happy Music Video

TORCHES (6): A RPG Microblog Collection 7


Over on bluesky, Zenopus Archives posts a new favorite Holmes/OD&D house rule: "...that thieves can fire into melee without penalty; i.e. no friendly fire". This is a great rule and keeps positioning thieves as a specialists in combat. While they still could use a spear in the second rank, thief PC could be out of rank acting as scouts/recon- this rule allows them to use that position and further encourages the *risk* of breaking rank.

Death, Taxes, & the City Guard: Blog of Forlorn Encystment summarized some very nice rules buried in the AD&D DMG about the city guard having indentured magic-users, taxes on goods, and highlights that by applying taxes- your PCs will try to find ways around them, which is fun. Also this is an excellent reason to have a thief be connected to a guild- black market downtime. Good to note too His Majesty the Worm incorporates a 50% tax rate for this very reason!

Megadungeon Zine (n.): Casey Garske of Stay Frosty fame has put out a new megadungeon 'zine Oubliette using Google docs, public domain art, and his own pencil art. Two issues so far with "0" being a small player's guide and "1" being the first level of the dungeon. I love this old-school G+ energy. We need some more of it in the space. The early old-school scene has a lot of these sorta 'zines and I try to collect as many as I can. It's a lot of similar energy found in many Appx. N Jam entries.

And speaking of megadungeons, Castle Kelpsprot is being put out by The Dododecahedron. Yet another to check out and apparently it already has hundreds of rooms keyed.

Mouth of Mormo: Speaking of dungeons, Goblin Punch released a new, free dungeon which comes in a highly annotated form filled with DM advice. In particular, I love: In my games, characters are required to have character goals. Why do you adventure? Why risk your life to search for gold in these horrible tombs? Character goals must be something that can be solved with money; otherwise, why is this character an adventurer in the first place?

Speed Dice for Fast Combat: A-new-to-me-blog, Light From the Far Horizon, has an interesting combat system where a weapon's damage die (the speed die) is rolled for the to-hit. If you are a lower roll than your target's roll, you strike them first before they strike you, but armor is ablative. However, two-handed weapons have to roll above the target's speed die. Sheilds get their own speed die, which you have to beat as well to strike. Its seems like a lively and interesting system. 

d666 Dungeon Dressing Table: Who doesn't want a table of "stuff you'd expect to find in a dungeon" to "gonzo/anachronistic mythic underworld bullshit"?



DOWNTIME DEMANDS OF SENTIENT WEAPONS: Or The Care & Feeding of Excalibur

Elric & Stormbringer
by Piotr Jablonski*

Sentient weapons and magic items should be like an annoying NPC

With great power comes a great lists of spurious demands. No matter if the object contains a true soul or is more similar to an arcane AI. Jennell Jaquays had great magic items like Tim the Fish Amulet with a great personality and several items in The Dark Tower, which had their own goals. And of course, Stormbringer is a character all its own in the Elric saga.

To me, a sentient weapon is not human. It understands its own purpose very well and desires to execute above all else, all the time. It finds it very hard to relate to its human welders. If for some reason it can relate, well most likely it was human at some point and that usually means a lot of baggage. I mean just look at vampires- they were once human too.

There can be positive benefits too. It might be that adorning the weapon or building a shrine could attract attention from other factions. Maybe knight errants come to kneel at an alter to the sword and offer a week of service. Maybe when traveling, the PC increases the disposition of neighboring towns towards the party as rumors of the sacred Mirror of Stars- perhaps even the queen seeks to know her baby's fortune.

Below are d20 such demands to be rolled during downtime periods. The request must be performed during the following downtime. If not, roll on the hireling negotiation table. Should they be ignored, a magic weapon will be just +1 and will refuse to perform any but innate functions. After all, the great Sword of the Sky is no mere rapier! Its not meant to just hang about your person like 50' of rope or that thuggish crowbar!

Demands of Sentient Weapons (& Perhaps Of Other Intelligent Objects)

  1. I should be oiled or polished with expensive agents

  2. Fancy display case or scabbard of rare materials

  3. I wish to be paraded

  4. I wish to be better known

  5. I should be utilized 3 times next delve

  6. I desire to walk around in your body, let me possess you

  7. A change in scenery is needed; we should travel to the next town

  8. You must carouse with me; excitement is needed

  9. You should commission a poem about me

  10. I should be housed for a week in a place of worship aligned to my purpose

  11. Your skill is weak- practice with me 1d3 weeks (PC cannot adventure)

  12. The king/lord must hear of my exploits, seek an audience and tell them

  13. Three foes should be struck down by me

  14. You should appreciate my other talents (only use innate or non-combat talents)

  15. You should know my history and place in the centuries, find it!

  16. You only need me and no other protection! (Wear no armor)

  17. Announce me with vigor! (All to-hit attempts are prefaced by a player battle cry)

  18. Your vestments should match my regalness and you should bear my icon.

  19. Your flesh shall rot, I am eternal- designate who shall bear me when you die

  20. You are an adequate bearer, nothing is needed…today.


*Really wish I had picked up these Elric reprints from Centipede Press when I had the chance

THE UR-GODS: Matter, Time, Energy, Thought, & Entropy

In the Rules Cyclopedia, there is a section on anti-magic that explains what is is in terms of RC Basic D&D game. And in that explanation, is brings up that all creatures on the prime material plane are made of four components: matter, time, energy, and thought, but that creatures in the astral plane might lack one of those components. Here is the passage below:


It is interesting here that one could devise a pantheon of gods around these 5 forces. But given that they are so primal and foundational, I view them as the D&D version of the Greek Titans. They are the gods of gods, but more specifically, they are forces that underpin the gods. And I see them as also falling along the Law-Neutral-Chaotic axis presented in basic: Matter & Time (Lawful), Energy & Thought (Neutral), and Entropy (Chaotic). 

So could these be the gods of a campaign? Are these concepts too abstract for players to role-play? And why do they all still allow turn undead?

And I think it might be interesting to consider monster design in terms of taking a vanilla creature and removing one of those 4 forces. Like, what do you get if you take "frog, giant" and remove matter, energy, time, or thought?

NIGHTWICK ABBEY: The Purple Eater of People, Session 124

 


Want to learn more about the world of Nightwick from Miranda? You can follow her blog here and the ongoing development of Nightwick Abbey at her Patreon here.

Previously in Nightwick...

Blossom (Rogue 6)
Mayfly (Magician 6)
Thekla (Magician 5)
Ulf (Magician 5)
Liminal Space (Changeling 5)
Poppy (Fighter 5)
Pataki (Graverobber 4)
Yevgeny the Coward (Cleric 4?)
Felix (Dwarf 1) 

At the Medusa's Head...
The group deliberates on any "unfinished business" on the first level. Meaning, what foul captains of the Pit have not lost their heads to our hands. We settled on one last target- the [REDACTED]

...Then Down to the Abbey...

  • The party had to flip way back to their older maps in order to chat a path through the Abbey's upper works (PC NOTE: mapping works y'all!)
  • The trip should have been easy, but a colony of fungal zombies halted progress but a fireball from the hands of one of the party's many magicians sauted those 'shrooms (PC NOTE: seriously, our party is spellcasters and thieves...and the Dark Country's most beloved being- Liminal)
  • The fungal zombies cause further deliberation since they generally reside on lower levels- is something pushing up? Worrying as these same monsters laid low Sotar, a Cleric of the 4th level (RIP to a real one)
  • We also visited the [REDACTED] to show it off to the new party member and ended up tusslin' with some goat men who had ample coin and a figurine of the Lady (uncorrupted; 500sp)
  • This led us to the lair of our intended target, which is cut off from the rest of the Abbey. We experimented with a few different ways of reaching the beast and found success in rotating magicians out in a tense moment of trying not to die every 3 rounds.
  • In the end we were able to walk away with some new spells, silver, and furniture!
...And back to the Medusa's Head
Together this action clear the first level of all the "hot-spots", but the presence of the fungal zombies might mean we've just cleared space for a new foe to make its home!


TABALDAK'S GEAS: The ICL 2025 Appx. N Jam Entry

 


Last Thursday, I submitted an entry to the 2025 Appx. N Jam! 

The Appx. N Jam was an itch.io contest requiring submissions to be a four-page RPG adventure based on a made-up book title that was randomly assigned. Those titles were of the vein of those old swords & sorcery novels found in the AD&D DMG's Appendix N- the influences for AD&D listed by Gygax.

For a great collection of Appendix N stories, I would like to recommend Appendix N: The Eldritch Roots of Dungeons and Dragons edited by Peter Bebergal from MIT Press.

I was hoping to get a title such as [The Location of the Noun + Noun], like "Crypt of the Red Wizard". This sort of title gives a clear idea about the dungeon and the random encounter table.

Instead, I got "Tabaldak's Geas", which, while it gives a potential antagonist, a "geas" is not a location nor something that could be easily used as a treasure. Furthermore, a geas in the D&D sense often forces the players to do X. For example, in OD&D, running across a wizard stronghold might result in a geas being applied to the party, forcing a task of some sort.

So I decided to combine ideas that had been kicking around for the Appx. N Jam:

  • The idea of the Deck of Many Things has been used as a campaign starter since its often considered a campaign breaker
  • A cult based around mistaking a beholder-kin (which has create food & water) as a bounty-delivering god
  • Try to submit a fairly good-sized dungeon (I hit 23 rooms)

Here is the synopsis I created for the dungeon:

“Who has misfortune thrown into this trap’s jaws?"

Escaping danger, the PCs are trapped in the villa of an inscrutable, unscrupulous, and absent sorcerer, the Lord has gone mad, the Captain is hopeless, the Vizer is obsessed, & the Friar turned heretic...

The only way out rests under the baleful gaze of The Eye!

This 23-room dungeon villa tasks the PCs with finding a way to escape the powerful geas that holds them prisoner. They will have to navigate the dead that the geas won't let rest, hungry familiars angry at their abandonment, candle-wax doves that hate light, and a dream-mad lord stalking the halls. All the while, they will puzzle over the tria prima, bemoan a mask made of cheese, tame a desk with a nasty disposition, and ponder the black lacquor box below the alien monstrosity at the center of the villa.

An adventure for four characters levels 1-2 (or twice as many level 0)

I'll try to do a more specific post-mortem after the Jam is over, but overall, I am very pleased that I was able to create, key, and design an old book cover for the Jam. And look forward to maybe doing it next year or participating in other design contests. Below is the map and random encounter table.


If you are interested in other designs that I've done, please check out the free Designing Dungeons course I co-wrote with Josh, the 2025 SILVER ENNIE (Best Game & Best Rules) award-winning author of His Majesty the Worm