Dungeon Design: Dungeon Ecology

Surely designing a dungeon badly is a doddle – just sketch some rooms out and randomly stock them with monsters and treasure? That’s true up to a point, but taking extra time to consider the dungeon’s ecology is design time well spent.

By William McAusland (Outland Arts)
By William McAusland (Outland Arts)


I’ve previously talked about the big picture when it comes to dungeon design. Just as important, though, as questions about who built the dungeon and why are more mundane details. The devil is in the detail, after all. Ignoring the basic characteristics of a dungeon and its inhabitants can shatter the players’ suspension of disbelief.

The Ultimate in Bad Design

  • It’s Magic! This is the ultimate rationale for lazy design. “It’s magic” can sweep away almost any logical inconsistency. All it says to me as a publisher (and gamer), though, is that either the designer doesn’t care about creating a plausible dungeon or he doesn’t know he’s failed horribly. (Of course, some extra-planar dungeons or the lair of a powerful wizard could prove the exception to this rule, but such examples are few and far between).

The Basics

  • Food & Water: Of course, some dungeon denizens – elementals and undead to name but two – normally don’t need to eat or drink. Most others, however, require sustenance to survive. If the means to acquire food and drink do not exist in the dungeon they must be acquired elsewhere (preferably from somewhere close by).
  • Access: Pretty much every denizen of the dungeon needs to move about. Creatures need to gather food and water, at the most basic level. They may also trade or work with their neighbours, creep forth to raid the surface lands and so on. To do this they need to have access to a means of entering and exiting the dungeon. The classic example of this done badly is the monster living in a room that is only accessed through the lair of another. Sure, the two might be allied, but would you really live in a place in which you were totally beholden to your neighbour for everything?
  • Conflict & Alliances: It is very unlikely the denizens of a dungeon exist in a bubble of isolation, not interacting with each other. As in any community, alliances, rivalries and conflicts will be present among the dungeon denizens. Clever explorers can learn of these and exploit them to their advantage.
  • Why Are They There? Consider why the denizens are actually living in the dungeon. Have the chosen to be there? Are they trapped? Are they here because they are searching for something? Shocking, most monsters don’t just hang around in a room waiting to be slaughtered by rampaging adventurers.
  • Light: While most won’t, some dungeon denizens need light. If they need it, they must have a means of providing light practically continually.

Unoccupied Rooms

Empty rooms are a vital part of dungeon design that have fallen out of fashion in recent years through the tyranny of falling page counts and increased space given to the crunchy bits of modules.

Unoccupied rooms can contain furniture, hidden secrets, interesting dungeon features and even treasure! Skilled players can learn a lot about a dungeon by poking around empty rooms.

Dungeons need empty rooms because:

  • Provide a Change of Pace: They provide a break from the constant grind of combat that often occurs in dungeon delving and allow players to catch their breath.
  • Enable Skill Checks: Such locations practically beg to be investigated. Perception checks, Knowledge checks and so on can all be used to learn more about the location. Canny players can use this information to their advantage. If, for example, the party explore an unoccupied barracks and note there are 20 bunk beds in the room, they get a good idea of the size of the garrison.  That could be very useful information to have.
  • A Place To Rest: If the party are in need of rest, an empty room is the perfect place to hunker down for the night. An easily defensible, empty room or one that is remote from the main complex is even better!
  • Verisimilitude: Not every room in a dungeon should be stuffed full of villains waiting to be slain. Some rooms are used for storage, meeting, sleeping or ceremonial purposes. They won’t be all occupied all the time. If every room is occupied by foes it is very hard for the PCs to move through the dungeon without every denizen charging to the aid of their companions. Such a situation usually ends up in a very large, bloody and long-winded fight the PCs have no real chance of winning (and is probably crushingly boring).
  • Dressing: Empty rooms can be interesting places to poke about. They can contain interesting odds and ends that although not intrinsically valuable build on the flavour and style of the dungeon.

Help Fellow Gamers

Do you have any other dungeon design tips related to this topic? If you do, please leave them in the comments below and help your fellow GMs design better dungeons today!

This article is part of Dungeon Design Fortnight. Dungeon Design Fortnight celebrates Raging Swan Press’s upcoming release of GM’s Miscellany Dungeon Dressing – a huge 336-page tome dedicated to all aspects of dungeon design and dressing. This article, along with loads of other useful information, appears in the book. I’m insanely proud of GM’s Miscellany Dungeon Dressing and I hope if you are thinking about designing dungeons you check it out.

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Creighton is the publisher at Raging Swan Press and the designer of the award winning adventure Madness at Gardmore Abbey. He has designed many critically acclaimed modules such as Retribution and Shadowed Keep on the Borderlands and worked with Wizards of the Coast, Paizo, Expeditious Retreat Press, Rite Publishing and Kobold Press.

10 thoughts on “Dungeon Design: Dungeon Ecology”

  1. Hi!
    First of all, thanks a lot for your great website full of good, thoughtful and inspiring articles.
    I am surely going to buy the Dungeon Dressing book!
    I have one question in that regard, because you list it as being available at Juli 31st. But its already available printed at amazon.co.uk – and it’s in my shopping basket 🙂
    I ask because i just want to be sure that the book im seeing at amazon is the correct one (it looks to be!) and not an older release or something else.

    1. Thanks so much for the kind words! I’m rather chuffed!

      If the book is called GM’s Miscellany: Dungeon Dressing and it’s this one then that’s the one. Naughty Amazon must have listed it early! (And don’t forget if you buy a physical copy, I give you free PDFs! You can check out the deal here.

      Thanks again for both the kind words and the purchase. I hope you enjoy GM’s Miscellany: Dungeon Dressing

  2. Hello

    Love your stuff and noticed this post of ideas, for the fun of it I decided it might be good to build on what you have here. The quest of a realistic dungeon is one that fascinates me to no end. In reality the deep parts of the earth are like deserts actually and not full of life.
    When dealing with monsters, beasts and humanoids its best to think of their bellies first. Most will be some form of meat eater and nocturnal hunter. So the most important thing for any mega dungeon that needs to eat is grass. See grass takes the energy of the sun and converts it to food for herbivores’, the most likely food source of a dungeon, be it a cow, elk or other creature. The locations of the entrance should be where a ready food source can be found, this allows hunting grounds which really is the source of wondering monsters. These hungry monsters will come out at night and track down and kill their food, the scavengers from the dungeon will follow after to get there food as well.
    During the day, being the safest time to enter any dungeon these monsters and beasts will most likely be sleeping to conserve energy, huddled away in some location in the dungeon digesting there last big meal, intelligent creatures will set some form of a watch and would also be mostly sleeping as well. Depending on how deep the dungeon is, seepage from aquifers will offer plenty of water with flooding occurring during heavy rain (another time to stay out of the dungeon).
    There will be plenty of sign of the beast’s presence from waste material to tracks to the smell of musk, the floors dirty with tracked mud and places where a band of adventures was caught and eaten. This would be the same near any place where the monsters enter and leave the complex to hunt.
    Deep dungeons tend to be a problem, water might be present but not food, from a logic standpoint the dungeon would not get more dangerous the deeper you go, but safer as the worst monsters would be close to the dungeon exits, so hidden entrances to the deep levels would be a must.

  3. Another reason for some empty rooms is to enable stealth characters and parties. Let us say that a ninja has 2 doors to choose from. Behind the first, there is an empty room, but light and voices coming from down a corridor at the opposite side of it. The second door is filled with the sounds of eating and conversation.

    In the old days, a lot more of our time was spent sneaking about.

    Warm regards, Rick.

  4. One thing I always remember is that – even if they are filthy and don’t wash – your dungeon denizens generally need to use a restroom. Whether they have a mere hole in the ground, do it where they stand or have nicely fitted out bathroom facilities, they all need to go. Well, perhaps not if they are undead. So make sure that facilties are provided…

    … unless of course, you are visiting Hell. Eternal damnation without relief, remember?

  5. I’m not sure why this showed up on my facebook feed today, but here it is.
    I’m a big fan of empty rooms for all the reasons you mentioned, but I also find them useful if you’re trying to build suspense. If you’ve started dropping hints about the hideous, powerful BBEG, then having empty rooms the PCs pass through where they can hear growls, screams of victims, or even just end up in a labrynthine mess of rooms, can add to the the tension before the final encounter.
    Depending on the final encounter, having occasional interruptions by BBEG’s minions can add to the tension, but can also break it. You don’t want to drag it out for too long, as you don’t want the players to get bored. Difficult Perception/Listen checks can help with this, as the more failures, the more confusing the sound becomes.

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