Low-prep dungeons — a larval proposal

From a grain of sand to the darkest crypt beneath the earth…

The basic idea

Have concentric levels of prep, from the very quick to the very detailed. Each supports the next, more detailed level — if you prep at x, then later find time to do x+1, little of your effort at x is wasted.

For each level, I have a target for average prep time to carry it out.

General notes

  • A “dungeon” is not necessarily underground. It could be a tower, a house, a dense forest area.
  • “a dungeon” is a bounded thing, although it may be very large. It may of course link to other named dungeons.

A gloomy descent into the earth of detail

Level 1 — improv to theme (three minutes prep)


Can be done on the fly as the PCs enter.

  • Name
  • A sentence summarising its nature
  • Challenge Rating
    • I use one of my own devising, basically a crude adaptation of the Pathfinder and 5e ones to the LotFP rules
  • Themes — three or so phrases about what’s in the dungeon

For example, here’s one I made on the fly in last night’s game (lightly edited):

  • Pitside Warehouses
    • Some crumbling warehouses in pitside. The memories of better days mixed in with desperate or feral interlopers
    • CR 1
    • Themes —
      1. Abandoned goods
      2. Criminal proceeds
      3. Falling apart


  • Freeform improvisation based on the above
  • Guess at time passing for light, random encounters

Level 2 — improv inside method (15 minutes prep)


  • Use On-the-Fly Dungeon Generation Using The Perilous Wilds
  • Decide on a rule for where critical items/locations are
    • Different dungeons can use different rules for this. A decision you make at start of prep?
      • e.g. once all the Theme boxes are ticked
        • This is the Perilous Wilds default
      • e.g. “the 8th room I place”
      • e.g. “only after at least one monster and one trap”
      • e.g. “there” i.e. at that location on the mapping page, even though it’s not yet clear how the map will lead to that
      • e.g. as a random chance or table
    • And the dungeon keeps growing until it is placed
      • That’s not a bad stopping rule – if the PCs keep exploring, they’ll either (a) find it or (b) hit dead ends because you’ve placed it somewhere already and the dungeon is thus no longer growing
  • Optional – create one or two keyed rooms and a policy for siting them


  • If a return visit, use Dark Heart of the Dreamer p21 to restock quickly (using Dungeon World dungeon moves)
    • (“Dark Heart …” is a free download)
  • Random map generation as you go
    • Make topological maps — rooms are boxes, corridors are just lines
    • Can be random tables, can be minds-eye1
    • Key rooms (at least their threat elements) on the fly based on the Dark Heart or Perilous Wilds method
      • Dungeon CR sets base of creatures and other threats modified then as per Dark Heart
      • Treasure etc is then derived from the creatures

Level 3 — map, perhaps abstractly (one hour prep)

Small dungeons2 — map topological rooms

  • Make a full topological map
    • If some map already (from play at level 1 or 2), build out from that
  • Key all significant room features
    • Use Dark Heart or Perilous Wilds model as a rough budget for dangers while keying, but don’t expect it to support all the detail you’ll generate here
    • If you want to subdivide effort further, iterate through the rooms, adding one idea (taken raw from your mind) each time. Then do a pass that integrates them to make sense.
  • Define either a random encounter table for true random encounters i.e. for things that move (or perhaps minor static features e.g. a dropped item, a small hidden treasure), or an adversary roster.

Large dungeons3 — zone exploration

Use The Angry DM’s “Zone Exploration” Model. From that, we will get random tables for lots of stuff inc known features, special rooms etc. The randomness isn’t so much “where are they” as “at what point/in what order do the PCs find them” – or “do the PCs find them at all before they get weak and retreat”

Level 4 — detailed (up to four hours prep)

  • All sizes of dungeon — map topological rooms
    • As with small dungeons at level 3

Level 5 — finely detailed (more hours prep)

  • As level 4, but with topographic/architectural map

And so on down (all hours prep)

Until we all are mad.

Things that are missing and that will haunt me like a ghost might haunt me

  • Any direct consideration of history — who or what made this place, and why?
    • This may be improv-supporting enough to warrant going in Level 1
  • Factions active in the dungeon, and what they might do during downtime.
  • Planned inter-room relationships. A crude example is “if there is light or loud noise in any of the adjoining rooms, then the spider there will hide in the rafters” but I’m sure there is much more potential than that.
  • Systematic intelligent responses
    • Random encounters can approximate patrols and the like, but intelligent creatures can coordinate to repulse a known invader. Less intelligent creatures may at least manage and instinctual “immune response” coordination.

1. As in “Look inside your head. See what is there. Tell the players about it.”
2. What is “small”? This is a good question.
3. What is “large”? This is also a good question.

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