Kilodungeon Definition

One of the things I like most about the OSR is how often old tropes are tossed by the wayside. Ask folks what a gnome is* and watch how many different answers you get. That said, I also like solid definitions. Having a clear category with specific criteria so I can say [a term] and whoever I'm talking to knows exactly what I mean. It makes exchanging ideas easier because everyone is already on the same page.

It's especially useful when describing game materials. Knowing that something is a megadungeon gives me specific information about scale, play style, how much of a commitment is required to use it (either as intended or hacked), and how much game time and enjoyment my players will get out of it.

Right now the terms I see used most often to describe dungeon sizes are:

One-page dungeon: Compact. Quick, light, and easy to use. Will probably get a session out of it, maybe two.

Microdungeon: A few rooms, maybe more than one floor. Quick to prep and run, but probably at least two sessions worth of stuff. Good for a site in a hex crawl.

Dungeon: The standard unit of adventuring space. Needs at least one read-through before running it, two if you're a conscientious DM. It's got multiple levels, plenty of rooms, maybe a distinct ecology of its own, and loot. Sweet, sweet loot. It's large enough to keep a party occupied for multiple sessions, but eventually they'll clean it out and move on.

Megadungeon: This place is your whole campaign. It's a world unto itself, an endless roil of brick, stone, and earthen chambers burrowing ever deeper. If you are lost inside, you'll never emerge. If by luck you find one of the scattered enclaves of safety and life, your descendants will grow never having seen the sun. A megadungeon is a huge commitment for both the DM and the players. Your game is here. You're exploring this endless maze and not going anywhere else. Granted, megadungeons tend to have a lot of variety in the form of factions, different underground ecosystems, and magically warped areas. It's still a lot.

The jump from manageable, discrete dungeon to sprawling, bottomless megadungeon is too extreme; especially when compared to how close in scale one-page and microdungeons are to the dungeon. It's more than a logarithmic step up in scope. We need something in between.

So we have the kilodungeon. A neat, logical step from the main dungeon unit to the mega-.

Let's define it. There's a lot of range between dungeon and megadungeon to cover, so we should give kilodungeons a distinct size/complexity band to fall into. Make it clear where they exist instead of leaving them in a gray haze of being either a massive dungeon or a tiny megadungeon.

The criteria required to be a kilodungeon is:

• 5 to 7 levels
• Multiple paths between levels
• At least 12 rooms/areas per level
• At most 60 rooms/areas per level
• Multiple exits
• A single cohesive theme

So the bare minimum needed to be considered a kilodungeon is 5 levels, 60 rooms, and 2 exits. The maximum possible while still in the range is 7 levels, 420 rooms, and as many exits as you can shake a stick at.

How did I come up with these numbers and requirements?

The level and room counts: I thought about the relative sizes and complexities of the dungeons I've run/been run through and aimed to have the amount of stuff in an average dungeon be roughly equal to one level of a kilo dungeon.

For example, Skerples' Tomb of the Serpent Kings is a solid-sized dungeon. It has 3 levels, 52 keyed rooms/locations, and 4 exits. Ignore the levels and flatten it down into 52 rooms, then make an area like that into 1 level out of 5 to 7. That's the step up in size I'm looking for when going from dungeon to kilodungeon.

The number of levels came from 1) looking at how many levels a dungeon usually has (1 to 3 is what I've seen most, sometimes 4) and wanting to go beyond that, and 2) just being realistic with my upper bound. Once you pass 7 levels or 420 rooms, it might as well be a megadungeon.

The multiple paths and exits: That's just good design. Can you imagine how boring a completely linear delve would be on this scale? Ye gods.

Also kilodungeons are large, but you can find your way out of them eventually. If you die or disappear in a kilodungeon, it's because you fell foul of a monster, trap, or your own poor planning; not because you had to settle down and make a life there after getting lost. It would be like deciding you live at the mall now because you forgot where you parked your car.

A single cohesive theme: The way I see it, a kilodungeon is a distinct, purpose-built structure. It has a specific role or job it was created to fulfill and it does that and only that. The role might be a necropolis, a stronghold, a mine, a magical research facility, whatever. The important thing is that the whole place is dedicated to its single purpose.

Megadungeons can have a wildly varying patchwork of interlocking cities, biomes, and architectural styles that make them feel like underground worlds. You won't find that in a kilodungeon. Kilodungeons have their own distinct flavor and stick to it.

Apart from size, that stylistic difference is what distinguishes a kilodungeon from a megadungeon in my eyes. When something is on the boundary between the two, ask yourself "How much is going on here? Is there one main theme?" If yes, it's a huge kilodungeon. If no, it's a small megadungeon.

*For the record gnomes are 12 foot tall, spindly, fungal beings with leathery skin that eat primarily tar. They are usually very well-spoken and famous for their complex, regionally varied tea culture. You can find them pretty much anywhere, but they're good at hiding, which is strange for something 12 feet tall that smells like hot tar and Earl Grey.