I think it's time for a quick recap. This is my first time doing "serious" dungeon design. I've made small 3 to 10 room dungeons in the past, but they rarely had that living well-crafted sense that famous D&D dungeons have (or ideally have). Getting over my intimidation, I tried to assemble a list of guiding principles to avoid common pitfalls like providing
meaningful choices, creating consistent logic, offering branching pathways and avoiding chokepoints (except where done intentionally and mindfully as a "gating" tool), presenting dungeon-appropriate traps as patterns that PCs can decode and interact with rather than "gotchas", having secrets and surprises for PCs to discover, and (since this is high-level) for actually challenging PCs with high-level capabilities both in terms of tactics/strategy and in terms of scope/dilemmas.
No pressure.
So my next step was to articulate the dungeon's theme, purpose, creators, current occupiers, and level. Done.
[SBLOCK=The Basics]
Theme: Krak al-Mazhar is the perilous mystic desert lair of the Brotherhood of True Flame built into a caldera.
Purpose: The players may choose to venture to Krak al-Mazhar for a number of reasons both personal and larger-scale (e.g. stopping the mage pogrom, getting ruler out from underneath the Brotherhood's leverage), and they have multiple ways they can go about approaching the dungeon both literally (multiple entrances) and metaphorically (sneaking, going undercover, assaulting the dungeon, guerrilla strike, etc.).
Creators: Mystics of The Fire Most Pure, devoted to maintaining the ever-burning braziers of the ruined city-state of Al-Anwahar, originally created Krak al-Mazhar as a sanctuary when they fled bloody civil war. They were guided by an asuras to that inhospitable spot.
Current Occupiers: The Brotherhood of True Flame and its servitors occupies the dungeon now, having emerged from the corrupted remnants of the mystics. The are led by The Bonfire.
Level: Designed for four to five 15th-16th PCs. Characters are anticipated to have 8th-level spells and clerics to have Destroy Undead (CR 3). The stakes of the adventure start off deceptively small and ramp up, with the Brotherhood quickly making the conflict personal and having the potential to expand into a long-term struggle imperiling an entire nation.[/SBLOCK]
Then I was encouraged to think of common sense aspects of design relating to food/water supply, breathing, sleep, and entrances/exits. Done.
[SBLOCK=Common Sense Design]
1. How do they breathe?
Most are resistant to fire damage which helps with breathing excessively hot air in places. Otherwise, there's ventilation thanks to a few shafts/lava tubes leading to the caldera's surface. Overlooks and "screen" doors (mashrabiya / jalis) let in airflow as well.
2. Where do they sleep?
They sleep in areas away from the hazardous fumaroles, in quarters (for mages and priests) or barracks (for mamluks and holy slayers).
3. What do they eat?
Precious little game lives in the Great Anvil, the most inhospitable desert in the land, however the Brotherhood do harvest scorpions and beetles, and hunt fire lizards, giant mason wasps, and dangerous salt worms (desert-adapted remorhaz). Because of this limited diet, they rely on trade with mysterious fierce janni tribes who don't mind charging exorbitant prices to the sinister cultists, or else shipments by their allied merchants usually via teleportation circle and sending stones (made of volcanic rock from the caldera). When food is scarce, they force captive janni to create food and water (a spell forbidden to their priests of Kossuth as it involves water).
4. What do they drink?
There is an aquifer deep below the caldera, but it has become tainted with chlorides & sulfides. The alchemists and priests of the Brotherhood have devised a means of extracting the acids/poisons to yield pure water (as well as useful ingredients for more nefarious purposes). Additionally, the Brotherhood stockpiles water in the event that something happens to their water source, though these stockpiles wouldn't last longer than 1 week if rationed, less if not.
Water from the dead.
5. Where do they enter/exit?
There are six ways into Krak al-Mazhar, the first five used by the Brotherhood, and the last unused.
- Narrow fissures lead through the steep sloping "hills" around the caldera, that invariably lead to guarded bridges; three of these lead into the upper levels.
- The main Gate of Mysteries opens into the heart of the caldera. This is used by slaves working the sulfur mines, entry and exit for new initiates to the Brotherhood, for military drills, and for the very rare departing/incoming caravan.
- A teleportation chamber is separated (and guarded + trapped with conditional glyph of warding) apart from the rest of the citadel, on the caldera's ridge outside the forbiddance spell.
- A two-way portal to the Plane of Fire is used for welcoming efreet ambassadors/messengers and sending out initiates / exploration parties.
- The Bonfire owns a golden mirror which he can use to open a temporary gate which he can also return through.
- Lava tubes used by salt worms (remorhaz) and sand worms (purple worms) trace their way under the fortress; they are kept at bay by the narrowness of the passages and by magical brass gongs that create a sound the worms dislike.
[/SBLOCK]
Then I assembled my list of potential Inhabitants for the dungeon. I revised this just recently, and think it's looking like a pretty fun assortment of bad guys. Might add a few more baseline monsters from MM if they make sense for certain areas, but generally when presenting monsters the PCs may already be familiar with by 15th-16th level (e.g. I avoided cultists

), I am trying to put a different spin on them. Like LN archivist mummies kept alive by The Bonfire for the glimmers of wisdom/lore he manages to glean from their cryptic raspy prattling.
[SBLOCK=List of Inhabitants]
New Monsters
The Bonfire CR ?
Tasked Genie, Guardian CR 12
Tasked Genie, Slayer CR 11
Elemental Monolith, Fire CR 11
Immolith CR 9
Angel, Asuras CR 8
Agha of the Imperishable CR 6
Cinderhaunt CR 6
Dune Stalker CR 6
Priest of Kossuth CR 6
Shig’harakhi CR 6
Skeleton, Blazing CR 6
Disciple of the Salamander CR 5
Flamedeath Fedayeen CR 4
Genie, Janni CR 4
Flame Horror CR 2
Mamluk of the Imperishable CR 2
Monster Manual variants
Cornugon (horned devil) CR 12
Pyrohydra (hydra) CR 11
Black Flame Zealot (asssassin) CR 9
Desert Terror (bulette) CR 8
Elder Flameskull (flameskull) CR 5
Hidden Fire Elemental (elemental) CR 5
Fire Scorpion (giant scorpion) CR 4
Kada, Dark Reflection (shadow demon) CR ?
Crypt Servant (wight) CR 3
Killer Mimic (mimic) CR ?
Monster Manual
Iron Golem CR 16
Purple Worm CR 15
Remorhaz CR 11
Mummy CR 3
[/SBLOCK]
And I have a work-in-progress list of potential Areas that keeps growing bit by bit. 28 distinct areas so far, with a few repeated frequent areas. Basic layout is around the Great Garden which operates like a courtyard linking various areas (a courtyard that happens to be trapped with a permanent
maze-like effect for the uninitiated). I've also started working on logical area adjacencies, like placing the Sacred Ruins, Tombs, Glassteel Cavern, and Dungeon on a lower level together.
[SBLOCK=Areas]
Numbered Areas (28)
The Caldera
Alchemy Lab
Barracks, Flamedeath
Barracks, Imperishable Mamluks
Bridge of the Asuras
Council Chamber
Crematorium
Dungeon
Gate of Mysteries
Glassteel Cavern
Great Garden
Infernal Hall
Insect Farm
Initiation Chamber
Kitchens
Library
Portal of Fire
Quarters, Shig’harakh
Quarters, Slave
Sacred Ruins
Shrine to Kossuth
Summoning Chamber
Teleportation Tower
Tombs
Tower of the Bonfire (with sub-areas like Bedchamber, Phoenix Egg Chamber, Wizard's Study, etc.)
Training Grounds
Treasure Vault
Water Oubliette
Frequent Encounter Areas
A. Armory
B. Bridge
C. Conjuring Trap
F. Fumarole
G. Glyph of warding
H. Holy Slayer Guard Post
L. Arcane Locked Barrier
M. Mamluk Guard Post
O. Office: list of supplies, reports from patrols, register of visitors, etc.
S. Storage: smithies, barracks, stables, food stores, trash disposal
T. Guard Tower
P. Sulfur Pool
W. Well/Spring
WI. Illusory Wall
WF. Wall of Fire[/SBLOCK]
And now I'm trying to figure out my next step. I'm very tempted to start mapping, but I am remembering [MENTION=4937]Celebrim[/MENTION]'s advice about how we think about gaming being perhaps more important than the rules/specifics themselves, and I think that applies in a way to dungeon design too. Maybe I can start at the beginning (from the players' perspective) now...
How do we learn about this dungeon? And how do we get there?
I have a couple NPCs/scenarios that can pass on information about the dungeon to the PCs, though I'm guessing that will be woven into the ongoing campaign organically as the PCs zero in on the Brotherhood's center of operations. This could be their own motivation to investigate the
pogrom of mages being perpetrated by the Brotherhood, it could be a
campaign of terror keeping a ruler under the Brotherhood's thumb, or something else I haven't thought of yet.
How do we get there? That has a couple answers, depending on what information the PCs uncover, but I'm going to go with the barebones simplest: An overland journey through the Great Anvil, a practically rainless hostile desert wracked by sandstorms and haunted by monsters, ruins of forgotten civilizations, and dark magic. Could I write for a travel journal or what?

I'm estimating a roughly 240 mile journey (10 days on camelback at a normal pace)...might use random encounters...might just have 4-6 prepared encounters to run as I see fit. OK, details!
[SECTION]
Encounters in the Great Anvil
Environment. Water is incredibly scarce and rain comes only once or twice a year. The foraging DC for the Great Anvil is 25 (see DMG p. 111). Temperatures during the day soar over 130° F (54° C), while at night they plummet to below freezing. Sandstorms wrack the Great Anvil almost weekly. Ruins litter the desert, including open-air strongholds once inhabitated by desert giants, tombs dating back to the time of Al-Anwahar (the ancient civilization from which Krak al-Mazhar was constructed), and secret vaults of Brotherhood mages.
Inhabitants. Beasts inhabiting the Great Anvil include giant fire beetles, giant vultures, swarms of insects, vultures, and perhaps a jackal or sand cat at the fringes. Travelers besides the janni* tribes and Brotherhood’s caravans are unheard of. Monsters include desert terrors (variant bulettes; see p.#), fire scorpions (variant giant scorpions; see p.#), giant mason wasps (good-aligned sentient giant wasps), hatori (giant crocodiles that burrow in the dunes), lesser ghuls (variant ghouls and ghasts; see p. #) and great ghuls*, sand worms (purple worms), salt worms (remorhaz), and man-scorpions called tlincalli (see
Volo's Guide to Monsters).[/SECTION]
OK, if I wanted to create a random encounter table I have enough to go on there.
Instead, I'm going to focus on about 5 encounters during their journey. These encounters are meant to build suspense, provide clues and NPCs to interact with, and reinforce the themes of the adventure. They're meant to get the players into the dungeon's mindset and foreshadow things to come.
The five encounters I'm brainstorming are:
- A Bottled Curse. The Bonfire has unleashed several powerful curses upon the Great Anvil, where the dark magic hungers for victims. In this case, the curse appears as a bottle amidst the remains of dead adventurers where some minor magic items (well, relative to most high-level games) can be recovered. The curse is a bit complicated but impacts their water supply, fouling decanters of endless water and making create food and water only produce 3 lbs food and 2 lbs water (enough for 1 humanoid). Need to think of ways so that remove curse doesn't solve everything easily...maybe a lingering curse upon all creatures drinking from the bottle and all water sources that were in its presence...so you'd need a whole LOT of remove curse spells to clear the curse?
- Call of the Asuras. The asuras Isheae appears from the PCs' campfire/light source, and beseeches their help recovering her divine flame which she invested in the first of the men to assume The Bonfire's mantle and has passed down through their line. However, the dungeon is warded by forbiddance preventing celestials from entering. Might like to add a twist here, but uncertain what...?
- Jann of the Haunted Lands. Nomadic wild desert genies insist on having the PCs as guests at a tent feast filled with dangerous foods. How gracious and cunning the PCs are will determine how much useful lore about the Brotherhood the janni relate to them, versus how many exaggerated myths they spread.
- Salt Worm Dunes. Keen eyes can alert the PCs to the danger of a remorhaz and its young burrowed waiting for prey. However tricking the remorhaz will allow PCs to recover a remorhaz egg (useful for trading to Brotherhood mages), and killing them will allow harvesting of thrym gland (also useful for trading with Brotherhood).
- Walkers in the Sand. A nasty sandstorm strikes, threatening to separate the party and cause them to get lost (in this high-level context "get lost" translates to spend 6 more hours in desert allowing DM to throw another encounter at party or utilize another of The Bonfire's curses). During the storm, lesser ghuls attempt to lure the PCs apart and ambush them one at a time.