So You Want to Build a Megadungeon

The worst thing you can do? Thinking too big.

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The Halls of Arden Vul. Rappan Athuk. Stonehell Dungeon. Pretty much anything by Greg Gillespie. All potent examples of the MEGADUNGEON - the granddaddy of all dungeons and eternal north star for any GM who’s fancied a dungeon turn for “strict timekeeping” purposes.

Admit it, you’ve wanted to make one of these before. Everybody does. Hell, maybe you’ve already taken a stab at it like all the poor souls before you (including, dear reader, the very author of this post). Maybe you’ve thought about how fun it’ll be to sit down and pluck away at some teensy tiny project, like a little daily affirmation.

“It’s easy, just gotta break it down into small parts! The hard part is showing up!”

And then you start working and you get a few days in and it starts to dawn on you:

“Well if I’m going to put this here, I really should start thinking about the real reason this dungeon exists…”

“Gillespie puts pantheons in his dungeons, should I figure that out first?…”

“Let’s just go on Reddit and see if there’s any advice — hold up, there’s a new version of OSRIC on Kickstarter??…”

And then, and then, and then…

Remember when you thought you’d make a dungeon for #dungeon23? LOL! LMAO EVEN!

You want to know the real secret to making megadungeons? Luke over at Murkdice has a solid idea, what with one of his newest posts on patching together smaller dungeons. It’s a solution I’ve come to myself, albeit in a slightly less glamorous way.

If Luke’s approaching the problem with a surgeon’s scalpel, I’m approaching it with a sawzall.

The great tool of creation is the knife. A better tool of creation is a reciprocating blade that has lots of little knives on it.

So, what is the solution?

Just build a bunch of 5-Room Dungeons and make them kiss.

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Making Megastructures, Mega Easy

I recently talked about a unique way to build dungeons using tetrominos that walks through how to make 5-Room Dungeons:

Building Dungeons (the Tetris Way)

I won’t rehash what I said there (go check it out at the link above and grab your free downloadable templates while you’re there), but I think I could convince you that building a dungeon with five rooms is easier than building a dungeon with over five hundred.

What else do we gain besides easing the burden? Turns out, quite a bit:

• 5 Room Dungeons provide a solid 1-4 hours of entertainment (in other words, a session’s worth of entertainment)

• You don’t need to think 400 rooms down the line, you focus on the here and now

• It’s much easier to iterate on the dungeon’s theme (more on that here)

“But,” you may be thinking. “What happens when the party decides to blow through Rooms 2 and 4 and starts butting up on the next series of 5 rooms that I didn’t prep?”

My sweet summer child…

… nobody said you need to pre-determine which rooms on the map correspond to the rooms in your notes.

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The Secret Sauce of the 5 Room Megadungeon

When you create your 5-room cluster for your next session, you should explicitly not predetermine which rooms are which. Describe the rooms in your notes, let the players explore, and place the rooms where they go.

If you have five rooms described and connected via cool encounters or story, congratulations: you just made dungeon design a tool you can flexibly use at the table. If the party is dragging, the next room is the combat room. Too much stuff happening to them? The next room is the reward room.

Mix and match as you see fit.

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Process in Practice: The Libram Mechanus

In my weekly DND game, my players have found themselves in an ancient library belonging to a long-gone super civilization. This place is teeming with lost secrets, powerful sentries, and all sorts of things suitable for a group of Level 17 characters.

NOTE: You may not want to read further if you consider yourself Fateless or an Heir. You’ve been warned. You cannot unsee how the sausage gets made!

I had initially gotten them here and then proceeded to panic as I wasn’t sure how to key an ancient library belonging to a super civilization. Presumably, this place would be huge and interconnected, which means I had to think ahead on a lot of individual elements that needed to seamlessly link together.

This place is also related to some major, campaign-defining quests the players have set out for themselves, so that makes the stakes of my prep even higher.

But I started to think the way I outlined above, using the 5-Room Dungeon method, and I realized I could chunk out the dungeon step by step — session by session.

I started with a theme, which was Ancient Advanced Technology. If you want to know how to choose a theme, I’ve got an article for that:

What Every Dungeon Needs

Then I built the first 5-Room Dungeon around that as follows:

1. Entrance: A strange, hologram-like being is an automated greeter to the Libram Mechanus. They cannot answer certain questions without proper clearances, which they explain can be given upon request at certain terminals or by Librarians. The room is filled with small crystal tablets that summon this greeter hologram at will, so the party takes one.

2. Puzzle / Roleplaying Challenge: Technically the third room they encountered, this room held a spherical filigree object within which resided a key. The object summoned replicas of the party members rendered in low-poly, each giving specific hand signals the party needed to replicate. After each signal, colored circles on the floor indicated where the corresponding PC needed to stand. Completing this puzzle, the party opened the filigree sphere and found half of a Disc Key - a pseudo-magic item that allows interaction with certain doors, terminals, etc. The rub? Once you activate a Disc Key, it permanently embeds into the keyhole until a Librarian loosens it with a command word.

3. Trick / Setback: Technically the second room they encountered, this room held an inset circular dais that was a few inches lower than the rest of the room. Surrounding it was a ring of floating crystals crackling with energy. The party hasn’t fully explored this room yet, as they were unnerved by the magic crystals, but inside the dais is the embedded other half of the Disc Key. If interfered with, the crystals launch spells that may paralyze the intruder and alert Libram sentries.

4. Climax / Big Battle / Conflict: In this room is a terminal with an empty circle that clearly fits a merged Disc Key. Surrounding the terminal are four “statues” which are actually inert sentries. These sentries will come alive in one of two scenarios: the terminal is interacted with in any way besides using the Disc Key, or any of the PCs have been marked by a sentry with an “Alert” status. Fighting four of these sentries simultaneously is a difficult proposition, as they are quick, merciless, and aim to contain the party rather than kill them. If they manage to access the terminal, additional details about the Libram Mechanus and its secrets are revealed, as well as some interactive elements to give the PCs an edge.

5. Reward / Revelation / Plot Twist: The party found this room at the end of the last session and made contact with a machine NPC they had met almost ten sessions ago. They never got to follow up with said NPC, so they did so here. They then learned how this NPC is related to the super civilization from the past, got some advice on accessing certain items the party was looking for here, and gained some advanced warnings about a particularly dangerous enemy here that may know intruders are prowling through the Libram Mechanus.

If you’re keeping track, the party’s progress went from 1 → 3 → 2 → 4 → 5, with the party not fully interacting with rooms 3 or 4.

They have some interesting choices to make:

• double back and try to get the other half of the key

• learn more about the terminal

• or press on further into the Libram

On the other hand, for me, I just need to build another 5-Room Dungeon. I can lean in on what’s happened so far in the dungeon, such as adding more Disc Key-activated objects, giving the party incentive to return to that dais in Room 3, and/or giving them additional pause on activating the terminal in Room 4.

And on and on it goes until — whoops, I made a megadungeon. The easy way!

Thanks for reading!

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