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You want to build a megadungeon. Not just a ‘big’ dungeon though, you want that whole vibe of sprawling connections throughout a huge space. You don’t want full procedural generation, you want intentional connections. It’s intimidating the fuck out of you because the truth is that’s a big task.

You don’t casually make something like Rappan Athuk or Arden Vul.

Over on the Murkdice discord, one of our members described prepping a megadungeon as a struggle. So I thought up a way to make it easier.

Start with parts

Don’t start with the megadungeon itself. Imagine our goal is a 300+ room, ten floor dungeon (which isn’t a big megadungeon but bigger than typical dungeons). Pick some themes: reptiles, rusting metal, hallucinations.

Design a dungeon. A normal sized dungeon. Let’s imagine you make something like this one, Death and Pestilence (for Mork Borg), which is 16 rooms.

I know what some of you are thinking: you can’t just design each floor as a disconnected dungeon. You underestimate me.

Make a load of individual dungeons with typical interconnectivity, enough to reach your target of 300+ rooms. They can be multi-levelled, anything you want. Stick with the themes you chose at the beginning.

Now for the magic.

Aggressive Reconstruction

Take each dungeon you’ve made. Roll a d4+1 and break it into that many pieces with some sense e.g. don’t seperate rooms that should be connected directly.

Now, take the number of levels you have and assign a die. In our case, ten levels means a d10. For each piece of the broken up dungeon, roll a d10 to work out which level it’s on. Alternatively, do this by feel if some bits should be higher or deeper and such.

Take the pieces for each level and assemble as you see fit. Now you have those long reaching connections spread across a huge space because these chunks of different threads are broken up across the megadungeon.

You might need to finesse things a bit:

• Unify the ecology of the dungeon

• Have factions make sense

• Unify the encounter tables

• Add in vertical passages

But the bones will be there in a way that is less intimidating than just sitting down to ‘make a megadungeon’.

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Visual Example

This isn’t megadungeon scale, but illustrates the point. I’ve cut up three Mork Borg dungeons into pieces.

Then I stitched them together into three levels, adding some vertical connections and such to get the bones there.

From there, combine encounter tables, unify ecology, and work out how the factions of these dungeons interact.

Living dungeons

Ever heard of 13th Age’s Eyes of the Stone Thief? It’s a living megadungeon that consumes surface structures, constantly adding to and rearranging itself. This technique is ideal for that kind of dungeon. You can swap the chunks over between delves or even when the PCs are in the dungeon.

For stitching together megadungeons, I write all my nonsense down in Muji notebooks (absolutely, 100% THE BEST notebooks) with a Lamy pen. Highly recommended.