#megadungeon

[oldschoolfrp]

Many horrors lurk in the deep dungeons of Undermountain, far below the Yawning Portal tavern, including illithids, beholders, and whatever that big stompy thing is in back (Karl Waller, Undermountain Adventures by Ed Greenwood from The Ruins of Undermountain box set, TSR, 1991)

[stonegearstudios]

On the Ruins of Giants

A small RPG about a big, decaying world

Art by @bedupolker / @bedupolker.bsky.social

Well, I went and got big art for a project I was only fiddling with so far, so I guess I need to make a proper post for it

Well, I went and got big art for a project I was only fiddling with so far, so I guess I need to make a proper post for it

Being small mice exploring the decaying ruins of the human world

Building up your colony so that it can survive

Traversing dangerously decayed and overgrown environments, as well as figuring out how to get your salvage back home

Dealing with all manner of mutants as well as seemingly unremarkable threats magnified by your stature

I have a lot of mechanic ideas that need testing (What dice to use, combat and positioning, character creation, exploration and more), and to do that I need to actually write them down outside of jot notes, so i guess I should get back to that

I have a few other posts about it (check the tags) but that's where I'll leave it for now. Little mutated lab mice in a big, hostile world. Coming whenever my ADHD lets me make progress on it. If you want to keep up, follow me here or on my bsky I basically never post unless it's about a project :V

One final thing, there's actually two versions of that pic, the original and one digitally tweaked, which do people like most?

Which version?

The Original (Brighter)

The Shaded One (Moody)

Voting ended onFeb 26, 2025

[maximumzombiecreator]

Since I've had a few people asking about megadungeon stuff recently, and I am an avowed megadungeon megafan, I thought it might be fun to walk through an actual example of megadungeon play that exemplifies what I like best about it.

This post is going to be the first in a series talking about a room from a megadungeon that I ran over 20 years ago (brushing past that fact quickly lest the horrors set in.) It was a major room, probably the most complex and important in the dungeon, and the players passed through it frequently throughout the campaign. In this post I'll introduce you to the room, and then in later posts I'll talk about what it does well and how to use that lesson more generally. Below the cut is a reproduction of the map as I remember it.

Without getting into The Lore too deeply, some dwarves accidentally dug into hell, as one does. Classic trope, nothing wrong with using them. They quite sensibly shut the mine down and sealed if off, but word got out. A human king heard about this, and took over the mine, expanding it into a temple complex to curry favour / barter with hell. It went badly, as such things do.

This concourse connects several wings of the dungeon, spanning several floors. An enormous devil face statue emerges from the northern wall, above the second floor balcony and below the fourth, and a column of light shines through a hole in the ceiling onto the center of the floor. Several floors of balconies overlook the chamber, though the stairs to the fourth floor balcony have long since collapsed.

This chamber was not too far from the main entrance, with the party first encountering it on their second delve into the dungeon, though it would take two more delves for them to gather the courage to enter it. At the time they first encountered it, it was swarming with imps and other little devils worshipping the big face.

I'll summarize the key:

A. Hallway from the Entry Chambers, the first and easiest section of the dungeon.

B. Doorway to the Pilgrim's City.

C. Doorway to the Unholiest of Unholies. Sealed and warded against simple spells.

D. Doorway to the Old Dwarven Quarters.

E. Doorway to the Nobles' Section. Barred from the far side.

F. Portcullis to the Pilgrim's City. The mechanism has rusted out and no longer functions.

G. Doorway to the Halls of the Clergy.

H. Doorway from the King's Inner Sanctum.

I. Doorway to the Archive.

J. Doorway to the King's Inner Sanctum, locked.

K. Doorway to The Indulgences.

Stairway from floor 1 to floor 2.

Light from the hole in the ceiling.

Broken stairs from floor 2 to floor 4.

Big ole devil face. Its eyes are a one-way illusion, allowing anyone within the face to view the room below.

Okay that's a lot, thanks for sticking it out. While I don't want to wander too far off topic into the rest of the dungeon, I'll just briefly note that the Pilgrim's City and Old Dwarven Quarters are easier sections of the dungeon, the Nobles Section and Halls of the Clergy are slightly more difficult, the King's Inner Sanctum, Archive, and Indulgences are very dangerous, and the Unholiest of Unholies is, as one might expect, where the worst things (and best loot) in the dungeon are. This was 2nd edition AD&D, so there was not a presumption of fights being balanced, and traipsing through more dangerous sections of the dungeon at lower levels wasn't uncommon. The players also understood the varying levels of danger fairly implicitly, since the custom at the time was that any time you went a level further away from whatever the ground floor was, things got more dangerous. The only exception to this is the Unholiest of Unholies and I think we can agree that when it's beyond a magically sealed door under a giant devil head the danger is telegraphed.

Next post I'll start talking about what made this room work so well in practice.

[tootallferne]

I should probably mention that I have an unholy amalgam of an OSR game over on at tootallferne.itch.io that I put out today. It's called the City of Shattered Clouds and it's got some really cool stuff in it. I even made a custom character sheet!

[vintagerpg]

Anomalous Subsurface Environment takes a novel approach to contending with the inherent irrationality of the dungeon by embracing it. There’s no secret at the center that makes it all suddenly make sense (in part because after two volumes — ASE1, 2011, and ASE2-3, 2012, both print-on-demand — the dungeon remains unfinished, but still, the introduction is pretty clear that there are no revelations to be had).

The dungeon came into existence spontaneously and persists thanks to a maintenance staff of self-created elemental spirits and defies any further explanation. The ASE was discovered in our own cyberpunk future by a megacorp that built large facilities around the ASE to research and extract profit. At some point, an unknown disaster forced the megacorp to seal the complex, trapping staff and resources inside. Fast forward 4,000 years into a retro-future resembling Thundarr the Barbarian, where the detritus of high technology mixes with magic and the ASE is, mysteriously, open for exploration once again. Thus, ASE is both as bizarre as its freeform funhouse ancestors but benefits from the narrative framework of modern megadungeons like Stonehell.

The central implication is that the system of the universe wanted dungeons to exists so badly that it just summoned one into existence, complete with all the silly game logic that had developed over the last 40 years, to see what would happen. The book present the ASE as the product of indomitable will that lacks driving intelligence. This is both brilliant and deeply, deeply weird. Watch out for the cornstalk warriors.

[shaneplays]

17 in Dungeon's "The 30 Greatest D&D Adventures of All Time", 1991's "The Ruins of Undermountain" by Ed Greenwood and cartographers Diesel, Steve Beck, and David Sutherland provides the first 3 levels (including subterranean city Skullport) out of Undermountain's 9 levels and 14 sub-levels lurking beneath Waterdeep. A large amount of the rooms and areas aren't detailed, allowing DMs to fill them in as they desired. The boxed set also included new Monstrous Compendium entries and cards with traps and treasures to place around your version of the setting. Will this megadungeon ruin you or make you… on Map Monday aka Dungeon Day!!

[brinefathomcaves]

Brinefathom Caves 2025 Year-End Update

Welp! I didn't get nearly as much done this year as I would've liked to, largely just because of mid-year procrastination. Then when I finally got my drive back in the waning months of the year, I had other creative responsibilities that limited my ability to catch up. I admit, I was also disheartened by the release of 5.5e, which I still haven't read in any detail.

I'm currently about halfway through updating the rooms for level 3. Level 2 is mostly done--I just need to write more about the various cults and add some more treasure. Oh! I decided a couple months ago that Brinefathom will be a GP-for-XP affair, so even with 5e's relatively low XP threshholds, I had to go back and add a lot of treasure. I also started writing the front matter for eventual publication and began populating the island-surface hexcrawl.

If you want to follow someone who's still doing cool daily stuff, I strongly recommend @fishrpg! His blues-themed setting Shadows in the Cotton already has a ton of interesting content, and he's working on polishing and expanding it into a publishable state next year.

In the mean time, thanks to everyone who's bounced ideas around with me this year, especially Fish and the members of the London-in-the-Air discord. Here's hoping I have more updates for you in 2026!

[rpgsandbox]

April is Mega Dungeon month on Backerkit.

Projects include:

Castle Zagyg for the Castles & Crusades RPG by Troll Lord Games, based on Gary Gygax's original dungeon.

Jewel in the Sky, a science-fantasy dungeon for the Cypher system by Monte Cook Games.

Hastening Doom for 5e D&D by Kobold Press.

Metadungeon for the DIE RPG by Rowan, Rook & Decard.

Castle Whiterock for 5e D&D and Dungeon Crawl Classics by Goodman Games.