Developing the Sandbox: Strongholds

This post is part of my series on developing the sandbox. You can read other posts in the series here. The series will, when necessary, go into detail on the development of my sandbox for Dungeon Module B1: In Search of the Unknown, but will also discuss sandbox development more generally. You can read play reports from my B1 campaign here.

In this post, I'll discuss the development of those strongholds in your sandbox which are ruled by NPCs. These are your classic fighters' bastions, wizards' towers, clerics' temple fortresses, and thieves' dens and hideouts, but it doesn't stop there. 

Paladins will rule strongholds somewhere between that of a fighter and a cleric. Rangers may rule fortified compounds in a more wilderness locale. Illusionists will disguise their strongholds to appear mightier than they truly are, or as simple earthen mounds or other natural features. Druids will rule secure woodland groves. Monks build monasteries. Assassins rule imposing wilderness fortresses.

Monster lairs can also be strongholds, and many famous "monster lair" modules play very similarly to strongholds. Bandits, berserkers, brigands, and dervishes may come to inhabit them. Giants and many underwater creatures will build strongholds as well. 

Two things that this post will not cover are (1) strongholds built by the player characters and (2) deserted strongholds, which are likely naught but ruins on the surface and which fall more readily into the dungeon category.

Most scholarship (i.e. blogs) on the subject of strongholds in D&D pertains to those built by player characters and the rules for doing so. I'm instead interested in how to design and key an existing NPC stronghold for the players to interact with. 

Strongholds are kind of like dungeons in the sense that the player characters can move from room to room and interact with objects inside. They will contain "empty" rooms, "monsters", traps, and treasure. They are also kind of like monster lairs in that they are home to a type of "monster" - broadly speaking, most often men and/or demi-humans, but more specifically, powerful NPCs that are very much like the player characters themselves, plus their henchmen, men-at-arms, special followers, pets, and the like.

Strongholds are tricky because they are very much real places, and complex ones at that. You'll want to have some knowledge about different types of real-world strongholds and how they functioned. You have to think about how real-world strongholds were constructed and defended, and anticipate ways in which your players might want to infiltrate or lay siege to them. You have to think about who all lives there and how much room is needed to house them.

Dungeons are similarly complex, but they're not exactly real places. It might be hard to imagine them without something historical to reference, but there are often robust procedures for designing them, and lots of advice on blogs. Because they're not really real, you can also let your imagination run wild. 

Monster lairs are "real" in the sense that bears and wolves and the like are a sort of "monster" that lives in our own world, and you can somewhat easily imagine what such a place would be like if instead an owlbear lived there, or what an otherwise normal cottage would be like if a leprechaun were instead its resident. They're also not usually especially complex, so there isn't a huge cognitive load when designing them.

There are also more fantastic elements to consider. What spells are laid upon the stronghold? Are there any monstrous inhabitants kept as pets - perhaps a subdued dragon or some enslaved monsters? Perhaps it's a stronghold like in OD&D, with heroes riding griffons and rocs, or defended by chimeras, trolls, manticores, and the like:

Just as you might steal some dungeons for your sandbox to lighten your workload, you can steal strongholds too. You can pretty easily steal the Keep on the Borderlands, Castle Ravenloft, the Hall of the Fire Giant King, or whatever. But you can't always steal exactly what you need, and you might want to create something original. It's not much fun to just use the Keep on the Borderlands over and over again. Is there a good adventure out there which features a fortified druid's grove? I don't know. I'll probably have to make one.

Because they are complex locations, inaccessible by design, ruled by powerful NPCs, and inhabited by large numbers of potentially hostile defenders, I generally assume that NPC strongholds will be one of the last places which the player characters explore in depth. Thus, they usually wind up at the very end of my list of sandbox locations to develop in more detail.

As with every location in my sandbox, before I go into more detail, I start with a minimalist sketch. For strongholds, this includes the stronghold type, who rules it, and how the ruler and their followers might react upon first meeting the player characters, as well as how they relate to those locations which surround them.

For the type of stronghold, I use this handy table from the AD&D DMG:

(Spoiler: The section on CONSTRUCTION AND SIEGE ENGINES really doesn't provide any details about castle types aside from how long it takes to build them. There's lot of information about excavation and mining - including notes on the efficiency of slave labor - a sort of glossary of castle features and how much each costs, and some rules for sieges. This section is kind of interesting, and the glossary is worth looking at, but it won't help you too much in actually designing such a location for your game.)

A castle can be totally deserted, deserted and inhabited by a monster, inhabited by humans (that is, bandits, brigands, berserkers, or dervishes), or inhabited by character-type NPCs:

Both types of deserted castles fall into the dungeon bucket, so we'll focus on just the other two types. There's another table for determining the type of humans in the castle:

In the case of character-types, it isn't as simple, because in AD&D, the stronghold ruler's class will also have some effect on what type of castle can be built. For example, a thief can only rule a small stronghold in or near a town or city, a monk can only rule a moat house or friary, and a druid's stronghold must be in the wilderness. This means that depending on which class is rolled as the ruler, we might be limited in which type of castle is possible.

I wrote up a handy summary of which type of character can rule a stronghold at what level and what type of stronghold they can rule, which is worth checking out. If you're not using AD&D, it isn't super important, but I think it's at least illuminating, and you can always use AD&D's tables for worldbuilding, even if you're using a different system.

Because the ruler's class affects what type of stronghold can be built and where, I determine that first using this table:

The level column is not quite accurate, which I elaborate on in the aforementioned post on the subject. 

In AD&D, only certain races can attain a high enough level in their class to build a stronghold. For example, only human clerics can reach a high enough level to build a stronghold, so if I roll cleric, I know my ruler is human. 

Similarly, if my stronghold is in the wilderness, I know it can't be ruled by a thief. If I roll monk, I know it must be a moat house or friary, and so on. It's a lot to wrap your head around, which is why I thought it worthwhile to summarize in that earlier post.

Knowing who my ruler is, I can then determine their alignment. This is also dependent upon class, such that paladins will always be Lawful Good, rangers always Good, druids always Neutral, and so on. This then modifies their reaction rolls pertaining to the player characters and their neighbors in the sandbox. 

Using my B1 sandbox as an example, I know that the brigands ruling Fayette's Hold are unfriendly towards Timbershore. They're not hostile, so they aren't attacking the town or riding around the countryside killing people, but they've occupied Ebongrove, the thorp at the foot of the castle and just outside of town, and are demanding tribute from Lambrecht, the wizard who rules his own stronghold in town. I also know that the brigands were originally recruited by Lambrecht to subvert the castle's rightful ruler, and that they're now holding the ruler for ransom. The people of Ebongrove are hoping someone will free Fayette from her cell. Lambrecht is attempting to court the ogres of Okorg's Den to aid him in retaking the castle.

That's pretty much all I need for a first draft for my sandbox. To get this location ready for play, I have to go deeper, starting with who all lives there.

In the case of bandits, berserkers, brigands, and dervishes, I simply use the numbers in the Monster Manual. For character-type NPCs, it will be more complicated:

1d4+1 henchmen, light and heavy cavalry led by fighters, and any additional special followers appropriate for the class. (If I'm interpreting this correctly, a cleric's stronghold is instead garrisoned by their special followers, while the other classes get both their special followers and the garrison listed above? Unclear.) 

The classes of henchmen are determined on a separate table than that used to determine who rules the stronghold:

This table yields slightly fewer clerics, fighters, magic-users, illusionists, assassins, and monks, and more druids, paladins, rangers, and thieves. I will ensure that henchmen are compatible with their masters, so a Lawful Good ruler will not have Chaotic Evil henchmen and a paladin will not have a henchman assassin. The level of these henchmen is determined by the level of the ruler:

If my hypothetical stronghold ruler is a Neutral Good 9th level human cleric, each of their henchmen will be 6th level, and none will be Evil. I find it fun to turn these henchmen into their own little "factions" of a sort, making opposed reaction rules with the ruler to determine whether they're favored, neglected, or on the outs, if they're fanatically loyal, unhappy, or actively seeking to betray their master. Remember that henchmen are, at the beginning, the pitiable wretches of the AD&D world, so it isn't hard to believe they might turn their cloaks if they think they might receive better treatment elsewhere.

A good example of this can be found in my Hexmas sandbox, the Jinglebell Barrens. The Tower of Noel is ruled by a fighter with several henchmen, each with their own personalities and agendas.

A stronghold's garrison will have a mix of from 38 to 64 men-at-arms (average 51). I don't love that this is unaffected by the size of the stronghold, so I like to roll as normal for a medium stronghold, roll twice for a small stronghold and keep the lower roll, and roll twice for a large stronghold and keep the higher roll. So a tower will have 2d4(keep lowest)+8 heavy cavalry, a large shell keep will have d4+8 as normal, and a fortress complex will have 2d4(keep highest)+8.

On to special followers. Clerics get a mix of cavalry and infantry:

Fighters get a medium level leader type and a company of either heavy infantry, crossbowmen, cavalry, or a mix of light cavalry and infantry:

Rangers are awesome and get 2d12 followers of mixed types:

This will mostly be normal stuff like character-type humans and demi-humans, but the lower you roll on 2d12, the more likely you are to get really cool stuff like giant animals, monsters, fey creatures, dragons, giants, treants, and lycanthropes:

This is the only thing in AD&D that really hints at OD&D's table of weird stronghold defenders, and that's too bad. There's no reason that your fighter's stronghold can't be garrisoned by griffon riders or your cleric's temple haunted by undead, but it would be a lot cooler if it was made explicit in some of these tables. Still it is really sick that if you play a ranger you have a chance of a dragon or giant just showing up to your stronghold to hang out.

Anyway, thieves get 4d6 thieves of 1st to 7th level and assassins (upon usurping the reigning Guildmaster/mistress) get 7d4 assassins of 1st to 8th level, 75% of which desert during the overthrow and are replaced by new 1st level recruits. There are more tables for those but they're not really worth sharing following those cool ranger tables.

After all that, you have to do the actual designing of the place, including layout and keying. Since strongholds are real historical places, you can do some research into each kind to figure out what exactly you're creating. You probably know what a tower is, but you might want to look up what exactly is a moat house or a shell keep or a concentric castle. 

Since medieval strongholds are not one of my special interests, I did some research. YouTube has a lot of videos describing different types of medieval strongholds, some with 3D renderings/walkthroughs detailing what might be found inside. I also watched some videos about how various defenses worked and how attackers usually laid siege to such places. I found it all enlightening and super interesting, and it's gotten my gears turning thinking about how I'd handle these scenarios in a D&D game.

The stronghold's character should be informed by the ruler of the stronghold. A thief's stronghold will be filled with nefarious traps. A magic-user's or cleric's will be warded by magic and protected by certain conjured beings. An illusionist's stronghold will be a very frustrating place indeed.

It's good to look over the list of spells available to the ruler and their henchmen to determine what sorts of magical effects might pervade the place, with a special eye towards those with a permanent duration. The stronghold may be guarded by animated dead. It may be lit entirely by continual light spells. Certain areas may be trapped with a glyph of warding. The stronghold may be surrounded by an overgrown thicket affected by plant growth. Locked doors may be affected by Leomund's trap. Other doors may be secured with wizard lock or affected by fire trap. A wall of iron may enclose the stronghold in place of wood or stone walls. Earthworks may be formed by move earth. An antipathy spell may repel attackers from a certain area. Clone vats may be found in one chamber. The windows of the ruler's chambers may be reinforced by glassteel. Permanency can make permanent the effects of enlarge, fear, gust of wind, invisibility, magic mouth, prismatic sphere, stinking cloud, wall of fire, wall of force, and web. 

There are many possibilities which will make the stronghold even more challenging than it otherwise would be, and this can quickly get out of hand. At the same time, this is the place where the NPC lives, so why shouldn't the wizard secure every door in the place with a wizard lock? Some spells will have costly material components or will be too high level to cast flippantly, so these should be treated with special consideration.

For the layout, you might consider using historical castle floorplans. As some of my contemporaries pointed out when I raised this subject, real-life castles are not super gameable. They are impregnable deathtraps which offer very little choice to player characters who might want to infiltrate or assault them, which is by design. They don't make for good dungeons. 

I think that's basically fine, because the types of strongholds in question aren't dungeons and aren't supposed to be. They're what the player characters' own armies of followers and men-at-arms are for - wargaming and sieges. This post isn't about adjudicating mass combat or siege scenarios, so although the topics go hand in hand, we'll leave them for now.

With a good plan the party might be able to stealthily scale the stronghold's walls and neutralize its defenders, or at higher levels they could teleport into the ruler's inner sanctum and confront them directly, but otherwise they'll need an army of their own.

...Unless there was some other way in. I seem to remember a famous D&D module which takes place in a dungeon built under an old NPC stronghold and a passing assumption in the AD&D DMG that player characters (and, presumably, NPCs) will always build dungeons beneath their strongholds. Such a dungeon could not only expand the functional square footage of such a stronghold, but also serve as a secret escape route for the stronghold's ruler in the event of a siege. And where there's a way out...

The dungeon beneath an NPC's stronghold is as important as the stronghold itself. Every NPC stronghold should have one. Like the stronghold above, these should be informed by the character of the NPC who rules it. You might go the B1 route and make this the mad labyrinth of a true dungeon sicko, or perhaps it is a more sensible extension of the stronghold itself - a series of cellars, cisterns, prison chambers, death traps, and treasure vaults. 

Is the dungeon garrisoned with men-at-arms like the stronghold above, or have they captured a menagerie of monsters and locked them down below to deter any would-be besiegers? This might be where the cleric keeps their undead servitors, or where the magic-user has bound their conjured elemental and fiends into service. This might be where most of the thief's traps are laid. 

Through the dungeon, the player characters might gain access to whatever area of the stronghold the ruler calls home. There will be guards to be dealt with inside, but it's still a lot better than storming the stronghold's walls and being peppered with arrows, bludgeoned with falling rocks, and scalded with boiling oil in the mad scramble over the walls. 

The assumption that characters will always build dungeons beneath their strongholds not only provides a more convenient way in for a small band of adventurers, but also a handy justification for defaulting to D&D's default mode of play, where the game is at its strongest. Whether intentional or not, it's a genius bit of design which simplifies a location which poses unique and difficult challenges for the player characters and DM alike.

In a way, strongholds are settlement, dungeon, and monster lair all in one. Preparing one for your sandbox requires you to combine approaches from all three of the former location types along with an understanding of the real-world places in our own history. It is no easy feat, and the resources provided by the game itself are somewhat lacking in this area. If you manage to design a good one, however, you'll be rewarded with a location that can support a variety of modes of play, from social intrigue to mass combat to your usual dungeon fare.

Developing the Sandbox: Monster Lairs

This post is part of my series on developing the sandbox. You can read other posts in the series here. The series will, when necessary, go into detail on the development of my sandbox for Dungeon Module B1: In Search of the Unknown, but will also discuss sandbox development more generally. You can read play reports from my B1 campaign here.

"Wilderness" monster lairs (really "outdoor" monster lairs, since they can appear in inhabited as well as wilderness areas) have much in common with other location types in the sandbox. They're kind of like dungeons, and kind of like strongholds. Monsters can have lairs in dungeons. A stronghold is essentially the lair of its ruler or occupants. The Caves of Chaos is the quintessential monster lair in classic D&D, but it looks very much like a dungeon and plays very similarly to a stronghold, the difference being mainly one of aesthetics and the "personhood" of its inhabitants (i.e., whether or not it is socially acceptable to kill them). The Hall of the Fire Giant King is a monster lair but is also literally a stronghold.

Lairs look different depending on who lives there. A monster lair might just be a room in a dungeon. Outdoors, it could be a cave full of owlbears, which is very obviously a lair, or it could be a leprechaun's burrow, which is visually almost indistinguishable from a hobbit hole. Your character might be a hobbit. To them, that's just a home! Orcs sometimes live in villages, and an enclave of elves is probably like a village too, albeit with a different aesthetic and inhabitants. Giants and vampires and such live in castles. All sorts of monsters can inhabit deserted strongholds.

Despite their similarity to other locations, monster lairs serve their own gameplay purpose and satisfy a unique niche in the sandbox. They vary in complexity. The cave which is home to a small pack of dumb beasts is simpler than the ruin where a dragon slumbers, surrounded by a few dozen sycophantic humanoid worshipers, which in turn is simpler than the underground city inhabited by hundreds of highly intelligent, organized Drow. 

In my own musings on the subject, I argue that monster lairs of lesser or greater complexity serve as "stepping stones" from one level or tier of gameplay to the next. Using my B1 sandbox as an example, the owlbear den offers something for the players to do after they finish exploring Quasqueton, but before they're prepared to infiltrate or lay siege to Fayette's Hold. The ogre den similarly offers a transition from that stronghold - with just a meagre garrison and a relatively less powerful fighter ruling it - to the strongholds of Lambrecht and Blachefleur, the Evil wizard and cleric who hold dominion over the town of Timbershore. If there were also a lair of, say, 300 orcs out there in the wilderness, that would likewise offer some "endgame" content for the players, perhaps after they've liberated the town from its sinister rulers.

Keeping in mind the relative complexity and challenge level of your monster lairs, you can make an educated guess as to which will be easiest to detail and which your players are likely to explore first, which will in turn inform the sequence you should follow when developing these locations. Going by complexity alone, I might first detail the giant eagle nest, Jinglepuff's Burrow, and the owlbear den first, for example.

You can also anticipate your players' likely actions based on the locations' proximity to inhabited lands. Going by this metric, I might first choose to detail any monster lairs found in Timbershore, then take on Zerelda's Camp (yes, a camp of adventurer NPCs is a "monster lair") and the ogre den because they are close to inhabited lands and relatively easy to get to. The giant eagle nest, Jinglepuff's Burrow, and the owlbear den are comparatively remote, so they could wait for later.

In reality, none of these locations should take long to detail, and any of them might become relevant sooner or later depending on the players' interests, so they all end up being developed during the same "phase" of my process. I just kind of jump around from one to the other depending on whichever one interests me next. 

The owlbear den seemed really straightforward, so I knocked that out right away. I had never keyed a leprechaun burrow before, so I did that next because it seemed fun. There was also a monster lair in Timbershore which really caught me by surprise (and which I won't spoil here), and was so delightful that I simply had to do it next. Have fun with it! Keep the momentum going however you see fit.

As usual, I will start with a minimalist sketch of the location. For monster lairs, this includes what type of monsters live there, who their leader is (if they have one), and how the monsters as a group react to adventurers (or the outside world more generally). 

Are the bandits led by a fighter? A wizard? A cleric? Are they actively riding around the countryside, killing, looting, and burning, or are they simply threatening and demanding tribute? They might be Robinhood types, stealing from the rich to give to the needy. Are the orcs causing problems, or just keeping to themselves? Are the elves reclusive, or interested in trading with the human population? Just because the "monsters" are not hostile "enemies" doesn't mean the place where they live isn't worth detailing!

Next, I'll hammer out specifics, like the number of monsters present and what treasures they possess. If you're using something like AD&D, the Monster Manual will simply tell you these things, which is awesome (keep in mind that the actual number of monsters appearing compared to the total possible number will affect the amount of treasure they have). X number of goblins appear in dungeons, Y wandering the wilderness, and Z in their wilderness lair. If they're in their lair, they have so and so leaders and a such and such percent chance to have this or these monsters as guards. It's great stuff.

You might be using some other resource depending on your system of choice, in which case you might have to fill in the specifics with your imagination. The thorough procedural structure of AD&D is one of the many reasons I find myself coming back to it when wanting to run a game.

Honestly, if you're running something like modern D&D, the AD&D numbers work just fine. Even if you're running 5e, try having a bandit camp with 200 bandits in it. That will throw your players for a nasty loop when they hear about the bandits plaguing travelers on the road and assume it's a quest hook for 1st level characters with a carefully balanced combat encounter designed for them to easily defeat, only to find that they need a small army to root the bandits out. The number of monsters suggested by AD&D is less about adhering to some esoteric underlying math and more about creating a lifelike world.

Once you know how many monsters there are and how much treasure they have, you will need to figure out how that's all distributed throughout the lair and convert it into a table-ready key. For small-scale lairs, I think it's quite easy. I use a variation of the same "chunking" method outlined in my post on developing dungeons. Let's revisit this table from the AD&D DMG:

In a dungeon, I treat a roll of 15-17 ("Monster and treasure") as a lair. In a 20-room chunk, there will be three of them. In this case, I really only need one. Since there are normally three, what if I just divide the whole table by three?

Since there are normally 12 "empty" rooms per three "monster and treasure" rooms, my smallest lair needs only four "empty" rooms. There is about a 67% chance of there being another room with just monsters, and about a 33% that there is a "special" room, a trick or trap room, and a treasure room, respectively. That means your smallest monster lair is most likely going to have about seven rooms (four "empty", one with the primary inhabitant and its treasure hoard, probably one with another monster, and probably at least one special, trick/trap, or treasure room).

This works pretty well for a single leprechaun's burrow or an owlbear den with just a mated pair and their cubs. If the lair contains 300 orcs, you'll obviously want to adjust it up so that there's room to breathe. You also don't need to take it too literally - just because there's only two "monster" rooms doesn't mean those are the only two rooms with monsters in them. There is probably an ogre monitoring the room with the hidden pit trap and another standing guard by the treasure den. This is where they live. Spread them out!

You will also want to loosely interpret the results, since this isn't a dungeon. The number of "monster" rooms isn't actually telling you how many monsters are there, since the Monster Manual (or whatever is available in your system) is probably providing that information. Those are just the rooms where the monsters congregate (i.e. where they eat or sleep). 

A "trick/trap" room isn't going to feature the same sorts of tricks and traps you'd find in a Mythic Underworld-style dungeon, but rather whatever sorts of devices the monsters in question might employ in their home, depending on the type of home they keep. These might be proper traps or simple obstacles, fortifications, wards, hazards, etc. Kobolds will set traps in their lair, but owlbears won't. A "trap" in an owlbear lair is going to look like something different. Similarly, the "special" room in the owlbear's lair might be a forgotten druid's shrine in the back of the den, accessible via a narrow tunnel, which offers some boon entirely unrelated to the owlbears themselves.

All this method is doing is providing the number of rooms and the proportion of gameplay features to include. For example, let's say I roll some dice and determine that, in addition to the requisite four empty rooms and the room where Jinglepuff is found with his treasure, his lair also contains an additional "monster only" room. 

Since Jinglepuff is the only leprechaun who lives here, and the Monster Manual doesn't suggest that leprechauns keep other monsters in their lair, I refer to my indexing of AD&D 2e monsters by level. According to that, leprechauns are a 5th level monster, so I go looking for something comparable that might reasonably be found there as well. Blink dogs are also 5th level monsters, and are associated with fey creatures, so I might decide that Jinglepuff keeps a mated pair and their litter of pups as pets (great for capturing and selling into slavery).

If I were to have the same rooms in my ogre den, however, I might say that the "monster only" room is just where the majority of the ogre rabble congregate to eat and sleep, while the "monster and treasure" room is where the chieftain and his favored consorts and bodyguards dwell. This is because the ogre lair contains more than a dozen ogres, while the leprechaun lair has just one leprechaun. In the former example, I'm spreading out a greater number of monsters across multiple rooms. In the latter example, I'm bolstering a single monster's numbers with additional pets and guardians which make sense for that monster to keep.

For a lair of 300 orcs, I could do a full 20-room chunk, with huge garrisons of orcs living in each of the "monster only" rooms, and the chief and sub-chiefs (or whatever) making their own individual "lairs" in the "monster and treasure" rooms. That's still 60 orcs in each room (or, more accurately, 60 orcs spread out across the rooms each group is responsible for protecting), so I might make it a lair with 40 or 60 keyed areas - as I said, these larger lairs can become very complex! 

This also prompts me to consider turning each of the sub-chiefs into their own factions within the larger orc band, since each has its own mini "lair" within the greater lair. This allows for more social gameplay and for turning one faction against the other to start an internecine war between them, not all that dissimilar from the Caves of Chaos. Might I suggest using opposing reaction rolls to determine how the different monster groups feel about one another?

Remember that just as strongholds and settlements assert their dominion via patrols, monsters will control their territory as well. Put some wandering monsters from the lair on your outdoor encounter tables. When monsters are found in a given area of the lair, note if who or what is there differs by time of day. If one cave is where the owlbears sleep, they're probably not there at all times. Perhaps one goes out to hunt for part of the day, while another stays behind to watch the cubs. Orcs hate sunlight, so you probably don't want to raid their lair during the day when everyone is home. If you go at night, some will be out hunting, which will make the raid that much easier.

Many of the same principles you might keep in mind when designing a dungeon apply to designing a monster lair. Jacquays it. Create a wandering monster table. Make sure the "empty" rooms still have interactable elements. If possible, include something to talk to, something to kill, something to be killed by, and a secret to find. 

You'll want the place to feel like what it's supposed to be - a place where monsters live. This is not the Mythic Underworld, impossibly old and inscrutable, with weird rules of its own, where the ancient and alien nature of the place can explain away a lot of the weirdness in layout or features. If your dungeon is filled with undead or fiends or elementals, you probably don't need to worry much about dungeon ecology, but a monster lair is usually home to a type of monster which is much more grounded in the physical world and its requirements - humanoids and beasts that need to eat, drink, sleep, procreate, raise young, go out and hunt, entertain themselves, make themselves comfortable, and the like.

Just as dungeon history informed the specific way in which I stocked my hypothetical dungeons in my previous post, the nature of the monsters that dwell in the lair (and the nature of the lair they dwell in) will inform the way in which I stock their lair. Elves will use magic and warp natural features to suit their needs, dwarves will use shifting stone and have lots of room for crafting, and halflings will keep cozy lairs with full larders. Orcs will decorate the place with the skulls of their enemies, kobolds will employ lots of traps, and cackling will echo through the gnolls' warrens.

Another key element is to ensure the lair suits the monster's strengths. This is probably less so the case in a dungeon, where the monster is more likely there by happenstance, and some other creature originally designed the space for their own ends. The monster chose its outdoor lair for a reason, or modified it to suit its needs. Giant spiders will carpet the floor with webbing to detect prey entering. Fire giants will carve channels for molten lava to form moats. Black dragons will flood some portion of their lair and keep their treasure on the far side of a submerged tunnel. A beholder carves tunnels using its disintegration ray, and it can levitate, so it isn't creating its lair to be easily navigable by pitiful grounded bipeds.

Not all lairs are dungeon-esque. An informal camp home to adventurers, bandits, berserkers, or the like it not going to play like a dungeon crawl at all, nor is a giant eagle nest situated in the branches of a tree atop a tall bluff. These are much simpler, and you can probably imagine easily enough what the place looks like once you have the specifics figured out.

Monster lairs are excellent sandbox fodder, which is great, because you'll probably have a good amount of them, depending on the method you use to stock the sandbox. I determine the number of monster lairs based on the terrain. They are less common in grasslands and desert, but more common in swamps and mountains. If my sandbox is in a more "rugged" "untamed" region, there will be more monster lairs.

They vary in complexity, but are not overly complex until you get to the huge humanoid warrens and villages. At the lower end of complexity, they're dungeonesque, offering turn-based exploration and heated skirmishes in narrow confines. These are not overly difficult to bring to fruition. At the higher end, they're akin to strongholds, forcing the player characters to accumulate power and bring real strength to bear to lay siege to them. These will require significantly more effort to design.

Because there are so many different types of monsters, and each monster will have its own unique version of a lair, they also offer a variety of thematic flavor which will keep your campaign interesting. Bear caves, elf villages, ruined giant strongholds, ankheg burrows, giant beehives, ghoulish graveyards, vampire castles - these are all lairs, and they're all wildly different because of who lives there.

Monster lairs are great because they affect the world around them. Most dungeons are kind of just there. The players will want to explore them because that's what the game is about, and because that's where the treasure is. Monster lairs also have treasure, but the game is also about dealing with monsters, and the lair is where you deal with them. 

That doesn't necessarily mean killing them. You might visit the goblin lair because the goblins have a powerful shaman who can cast a spell you need. You might wish to recruit them to attack the "civilized" frontier fortress where the really good treasure is kept. Maybe the local ruler wants to incorporate the goblins into their territory, the goblins are on the fence, and you're being sent to negotiate terms. Maybe the goblins are ruled over by the neighboring ogres, and they ask you to deal with them.

Be open minded about your monster lairs, what the monsters want, how they affect the world, and how the powers that be feel about them. That will color the way in which you expect the players to interact with these locations. Unlike dungeons, which monsters inhabit almost incidentally, lairs are where monsters choose to live. Why have they chosen to live there? How have they made the place their own? How has their choice to live there affected their neighbors? What, if anything, is to be done about it?

Developing the Sandbox: Villages, Hamlets, and Thorps

This post is part of my series on developing the sandbox. You can read other posts in the series here. The series will, when necessary, go into detail on the development of my sandbox for Dungeon Module B1: In Search of the Unknown, but will also discuss sandbox development more generally. You can read play reports from my B1 campaign here.

The subject of this post is the development of villages, hamlets, and thorps - that is, small settlements. For larger settlements like towns and cities, see my earlier post on the subject. The process of developing a small settlement will look similar to that for developing a large settlement, so it's worth it to revisit that post before proceeding.

Villages, hamlets, and thorps are the bread and butter of low level D&D. This is, I think, because they are relatively small environments filled with simple people with simple problems and a relative lack of agency in solving those problems themselves. It is much easier to come up with a low level adventuring hook like "Kobolds are stealing chickens" or "Bandits plague the roads" when there aren't high level character-type NPCs around to solve those sorts of problems themselves (although as I've argued in past posts, there are plenty of reasons why these powerful NPCs would not deal with these problems themselves).

Players characters tend to have more agency in these environments, regardless of their level, which makes them a great place to start adventuring, relative to towns and cities. Their actions have more impact in small settlements - they can offer immeasurable aid to its inhabitants, push them around, and make the places theirs, for better or worse.

That isn't to say you don't also need towns and cities. The latter offer a more complex, fantastic, and dangerous urban gameplay experience, alongside greater utility. It doesn't make much sense for the player characters to be able offload their vast sums of treasure in a poor village, hamlet, or thorp. There probably aren't many henchmen in such a place, nor are there likely to be high level NPCs to offer training, or sizeable factions to contend with. That's what towns and cities are for.

I don't find true-to-life medieval demographics to be much use in D&D, but they can occasionally serve as a helpful reality test. Take donjon's Fantasy Demographics generator, for example. Here is an example of what sorts of tradesmen might be found in the average AD&D thorp (population 50):

I don't really care how many chicken butchers and rugmakers there are in my D&D game, but things like blacksmiths, furriers, inns, jewelers, locksmiths, magic shops, spice merchants, and taverns can all be extremely relevant.

Here is an example representation of the average AD&D hamlet (population 250):

Here is an example representation of the average village (population (population 750):

And finally, for comparison, here is an example of the average town (population 4,000):

It's not until you get up to town-sized settlements that you start to have most of the trades reliably represented. Again, most of this is useless for your D&D game, but it is a handy reference point when conceptualizing these locations. If the player characters are truly in need of some specific good or service, they can't count on a village, hamlet, or thorp to have it. They must seek out the town or city.

What then are villages, hamlets, and thorps for? As stated previously, they are a great place for the player characters' adventure to start. They offer low level hooks and agency. They are a training ground for the more complex urban gameplay environments to come.

As with towns and cities, the first step in developing these locations will be to create a minimalist sketch including the settlement's population, any character-type NPCs who live there, who rules there, and the general population or ruling power's initial attitude towards the player characters. You can do this exactly the same way as you would for towns and cities. The population will be smaller, which means fewer character-type NPCs, which means less work for you.

The only settlement of this type in my B1 sandbox is Ebongrove, a thorp of about 30 people. There are 26 humans, 2 dwarves, 1 elf, and 1 half-elf. There are no character-type NPCs. I'll make a point to detail the four demihumans that live here, since they will stand out. If there were character-type NPCs, I'd detail those as well, and since there would be so few, I could really go into detail if I wanted to.

Since the thorp lies in the shadow of a castle to the north (Fayette's Hold), I decide that it is under that stronghold's protection. However, the stronghold has been taken over by brigands, who have imprisoned its ruler. The brigands are agents of Lambrecht (the Evil wizard who rules Timbershore) but are now in conflict with him. They lord over the thorp and terrorize the surrounding countryside. I place a detachment of 20 brigands with a 3rd level fighter leader in the thorp as an occupying force.

Another thing which distinguishes these locations from towns and cities is their size. Obviously, they are smaller. Unlike towns and cities, where the player characters must crawl from district to district and from one location to another within each district, possibly incurring random encounters, these settlements are all basically one "district", and the player characters can travel from one location to another more or less as they please. Nonetheless, I like to have a few locations and their relations to one another laid out, like so:

This is a small settlement in AD&D, so of course there are trifling treasures buried in cellars and gardens and hidden in taxidermized animals, saddlebags, and under floorboards. I also note where NPCs can be found at different times of day. There isn't really any rhyme or reason for the number of locations or nodes, aside from the fact that I wanted a seven-node "flower".

Since the thorp has a population of 30, I decide there are three militia people among them, which the party can recruit to help fight against the brigands:

The "-2 to recruitment attempts" is just an interpretation of a standard reaction roll. In this case, I rolled either a 4 or a 5 for this NPC, which is an "unfriendly" reaction. As you can see, I justified this modifier by leveraging the NPC's relationship to another NPC in the settlement.

Here, then, is the list of the remaining NPCs:

Because these settlements are smaller and more tightly knit than towns and cities, we get to zoom in on these otherwise unremarkable NPCs and focus on their relationships with one another, the small favors the player characters can do for them, and the favors the NPCs can offer in return. Player characters can earn the NPCs' aid by simply going up to them and asking them (which is where the modifier/reaction roll comes in), by doing them a favor, or by earning another NPC's trust (similar to how militia people are more likely to lend their aid if their family members have already been helped). This creates a web of relationships which is much denser than what I would prep for a town or city.

This is ultimately what distinguishes small settlements from larger ones. Because there are so many people in large settlements, we have to focus on the most important ones, and the rest become fuzzier as a result. Small settlements offer a different sort of "slice of life" gameplay wherein even woodcutters, charcoal burners, and shepherds become important. The player characters can show up and simply fight the brigands and run them out of town (or thorp, in this case), but they also have a bunch of places where they can get help, if they need it.

Again, there's no real rhyme or reason to the number of NPCs I've chosen to detail here. Including the militia (and not including the brigands' leader), I've detailed 14 here, which is almost half the thorp's population. That's probably a bit much, but I just tried to think of who all might be here and what sorts of aid they might be able to offer. Five or six NPCs might have been a perfectly fine amount.

Also worth noting are single dwellings, which are home to just 1d12 occupants, but appear in 3% of all hexes according to the AD&D stocking method. These may seem rather dull and unimportant, but they're a lot of fun. With just 6 or 7 occupants on average, you can really flesh these out as homesteads with either multiple families or as single family dwellings with lots of children, elderly parents, adult siblings, hired hands, and the like. 

These places are extremely vulnerable to depredations by monsters, so you can have the same sort of "Kobolds stealing chickens" hooks, or even something like "Our kid wandered off and there are wolves out there." There's also always at least a 1% chance that any of these people can be character-type NPCs. One of these days I'm going to roll up a single dwelling with just a 20th level wizard living there inexplicably and it's going to be awesome.

Since my B1 sandbox has just the one thorp, you can check out my B2 sandbox for an example of a village and some single dwellings or my B3 sandbox for a bunch of villages and a hamlet, albeit much less fleshed out than the example provided here. You can see how I'm able to give each of the character-type NPCs just a little bit more detail as a result of there being fewer of them overall.

Hopefully I've demonstrated how villages, hamlets, and thorps differ from towns and cities. It may be tempting to include just a grand city to cover all your bases, just a village because it's easier, or just a town because it sits in the sweet spot in between, but different types of settlements offer different things, both in utility to the player characters but also in terms of gameplay experience. Not every sandbox will have both. Not every sandbox needs both. But the variety will make your sandbox - and the gameplay which takes place there - richer for everyone.

Developing the Sandbox: Dungeons

This post is part of my series on developing the sandbox. You can read other posts in the series here. The series will, when necessary, go into detail on the development of my sandbox for Dungeon Module B1: In Search of the Unknown, but will also discuss sandbox development more generally. You can read play reports from my B1 campaign here.

I'll be honest - these days, I don't actually much enjoy making dungeons. You have to figure out what the dungeon used to be, who built it, what happened to it, who's been using it since, who's using it now, how they get along with their neighbors, where they live, (sometimes) what they eat and drink, what they're doing there, what stuff they have, what stuff is in the dungeon that they don't have, why they haven't gotten it yet, why are there traps, what the traps do and how they work, what a "special" room is, why whoever built the place would put it there, what the layout is, what the rooms used to be and what mundane stuff would be in there to play with, what are the doors like, which ones are secret, which ones are locked, how do the inhabitants get around, how many levels are there and how many rooms are there per level, where are the stairs, what's the percentage chance of encountering such-and-such while wandering around the place - the list goes on and on.

To compound all of this, there is so much advice to be found on the subject, whether it's in rulebooks throughout the many editions of D&D, other TTRPG systems, or online on blogs. It is really overwhelming to take it all in, decide what you like and what you don't, synthesize it all into a coherent methodology, and apply it when designing dungeons for your home game.

It's a lot of level design. There was a time when I really enjoyed that part of the game a lot, but lately, making dungeons has made me very frustrated more often than not. And then you have to write that all up in a key that's comprehensive while also being simple enough to run at the table. 

You have to put in similar work when designing a a stronghold or monster lair, but there's plenty of information about real world strongholds to draw upon, and monster lairs are often smaller, simpler, and easier to imagine. There are dungeons in literature, but few that actually emulate the D&D dungeon-ass dungeon. You're better off just reading old TSR modules to figure out what a dungeon should more or less be like.

I'm more of a big picture guy. I like making big maps with varied terrain, then finding out what all is there, whether it be cities, strongholds, dungeons, or monster lairs. Who lives there? Who rules it? What kind of monsters plague this or that region? How do they all relate? For me, that's where the juice is.

That's why I've basically just started stealing my dungeons. I originally decided to create my B1 sandbox because (1) I thought the dungeon-focused adventure was crying out to be placed within a larger context and (2) I really liked the idea of one of the more tedious parts of the sandbox development process (designing the dungeon) being done for me.

B1, however, does not feature a finished dungeon. The DM is instructed to roll to determine if each of Quasqueton's rooms contains monsters, treasure, or neither. This is relatively easy, however, since the module provides lists of monsters and treasure which the DM can place in each room when a positive result is determined. All that's left is to use the module's thorough room descriptions to figure out where the treasure is stashed, to determine how the monsters relate to one another, and create new wandering monster tables based on the monsters found in my version of Quasqueton.

I used some loosely interpreted opposed reaction rolls to determine monster relationships, eyeballing the map to find out who lives near who (combining groups into factions when appropriate) and who controls what territory. 

What I ended up with was some goblins who control the dungeon's entrance, some orcs deeper within who threaten the goblins and have lured away some of their numbers, and a few smaller groups of intelligent creatures and roaming non-intelligent monsters which are indifferent to the conflict. This has worked out quite well so far, with the players deciding to try to stay on good terms with the gatekeeping goblins, the goblins asking the characters for exchanges of favors, and the orcs launching attacks against the goblins when the party is away from the dungeon.

The DM is also instructed to roll to determine when doors are stuck, which requires more eyeballing to determine who can get into what areas, whose territory they'll need to pass through, and how that affects the dungeon's politics and who is aware of whom. For example, if the bandits must pass through goblin territory to get to the area of the dungeon in which they've been stocked, then the goblins must know about the bandits and have some opinion about them, and there must be some reason why they haven't killed each other.

For the wandering monster tables, I add up all of the monsters in the dungeon to get a total number of monsters. Then, for each monster type, I divide that monster type's total by the larger total to get a percentage. That is the percentage chance of encountering that type of monster wandering the dungeon.

Let's say I have a 20 room dungeon, and there are monster in five rooms: 11 brigands, 6 hobgoblins, 4 gnolls, 2 rot grubs, and 3 troglodytes. I don't think of the rot grubs as "wandering", so excluding those, I have 24 total monsters - 25% hobgoblins, 46% brigands, 17% gnolls, and 12% troglodytes. My wandering monster table would look like this:

d100    Monster
01-46   1d6 Brigands (from Area 8, looking to threaten, plunder, and rob)
47-71   1d3 Hobgoblins (from Area 17, killing any they outmatch)
72-88   1d3 Gnolls (from Area 11, willing to trade information for treasure)
89-100 1d2 Troglodytes (from Area 20, looking for sacrifices for the God of Stink)

(I'm assuming this is a 1st level dungeon, and the number appearing is based on the assumption that there will be 4 to 6 characters of that level, using my cataloguing of AD&D 2e monsters by level to determine roughly how many of each monster would be appropriate. You'll want to make it work for your own assumptions about party size and whatever system you're using.)

However, adapting B1 for my campaign wasn't as simple as stocking the dungeon, making a wandering monster table, and then using the module as written. Like, this isn't really usable:

There's an art to turning this into something that functions at the table. You can't read it as is. You could maybe skim it and put it into your own words on the fly, but you're wasting everyone's time. You could memorize it somehow, but good luck with that. My process has been to rewrite it in my own style, in a way where the interactable elements and the hierarchy of information is plain to see. In my style, this room looks like this:

Descriptive, but not verbose. Concise, but comprehensive. Important stuff is bolded. Bolded items are described in further detail. Additional information is available upon further inspection. I can eyeball the initial description and rephrase it in my own words, then go into further detail when the players spend time examining any one thing. This works for me. Yours might look different.

This is all very specific to my B1 sandbox, or any sandbox in which your dungeons are repurposed from existing published material. That isn't always the case. Though I don't love doing it these days, when I choose to do so (and I'm not wholly opposed to it - my sandboxes for both B2 and B3 include dungeons beyond those detailed in the published modules, after all), how do I design my own dungeons from scratch?

As with other location types, I'll start with a minimalist sketch. In the case of dungeons, this includes the type of structure it once was, who built it, how it fell into ruin, and (broadly) who or what dwells there now. 

In the AD&D 1e DMG, the ruin types are limited to deserted strongholds (with "mazelike dungeons thereunder" and the occasional monster using the surface ruins as a lair), villages (here I'd include the other classes of small settlement like hamlets and thorps as well), cities (or towns), tombs, and shrines. Tombs and shrines are classic dungeon fare. Deserted strongholds are good fodder as well, especially when considering B1 and how it depicts the maddening, hostile subterranean environments which bored, retired adventurers are likely to carve out beneath their seats of power.

Villages and cities are a bit trickier. They're not quite "dungeons" in the traditional sense. I tend to build ruined cities and towns as I would normally build a city or town, then wreck them. The characters can still crawl through the settlement's ruins district by district just as they would crawl through such a place were it not ruined. Perhaps it is now overrun by the doppelgängers, fiends, lycanthropes, and undead which have always prowled its streets. Navigating the settlement itself might be more akin to a point crawl. It's the locations which were once important to the settlement that are the proper dungeons. 

Using my B1 sandbox as an example, if Timbershore were to fall into ruin in the far away future, perhaps the remains of the Evil wizard Lambrecht's castle is one such dungeon, and the ruins of the Evil cleric Blanchefleur's keep another. Add in some crumbling manors or a merchant consortium's sealed treasure vault for variety. A ruined village, hamlet, or thorp could be much the same, albeit smaller and easier to get around. Instead of ruined castles and manors, a dungeon there might be an old mill or granary - a diversionary location with just a handful of rooms.

As for who built the structure originally, it depends. Strongholds are easy for me, since AD&D is quite explicit as to who can build strongholds and when, and the DMG has nifty (if not, at times, wholly consistent with its own rules) tables for determining who a stronghold's ruler is (or in this case, was). 

Shrines are built by clerics, so it's easy to determine who the cleric in question was - just determine their race and alignment and either pick some appropriate classic D&D god and genericize it for your setting or choose some god unique to your setting which you wish to highlight. If there were to be a ruined shrine in my B1 sandbox, for example, I would make it a shrine to the Horned Mother (Blanchefleur's deity), or I would come up with some other deity in opposition to her, its worshipers long since eradicated. I tend to favor either Evil shrines or Good shrines which have been desecrated by Evil powers. Remember that Evil undead are empowered in such places!

The ruins of cities/towns, tombs, and villages/hamlets/thorps are a bit trickier. I quite like the 2014 D&D 5e DMG's tables, which you can roll on to determine who built the dungeon, what type of dungeon it is, and why it was abandoned - so much so that this framework strongly informed my own ideas about creating the initial sketch of such a location. Still, who and what the tables include can be a bit of headscratcher. A dungeon might have been built by dwarves and elves, but not by gnomes or halflings. It might have been built by hobgoblins, but not by orcs. Beholders, giants, mind flayers, and yuan-ti, but not any other monsters.

Instead, it's probably best to look at what's already been established about your setting, and pick or randomly determine some appropriate creator based on that. My B1 sandbox is located in a heavily forested region, so perhaps a civilization of elves once lived there in the ancient past. Rogahn and Zelligar used orc slaves to build Quasqueton, and went to war with barbarians in the region - perhaps the orcs or barbarians had a civilization of their own and built structures which fell into ruin as the two powerful adventurers asserted their dominion over the place. There is an ogre lair in the area - perhaps their ancestors built things as well. Perhaps Timbershore once had outlying villages which were reclaimed by the forest, or perhaps it was once subservient to a larger city which met a similar fate.

The same approach works for dungeon history. Barbarians, ogres, and orcs may have brought ruin to human or elven civilizations and structures, and may have likewise been ruined by the campaigns of Rogahn and Zelligar. Perhaps there was a conflict between worshipers of the Horned Mother and whatever deity's worshipers had a foothold in the region before them. In addition to conflict from war and conquest, you could work in plagues, curses, and magical catastrophes.

All of the preceding information - the type of ruin, who built it, and what happened to it - can inform what lives in the ruin in the present day. A fighter's stronghold which was ruined when a subdued dragon rebelled might still be home to that dragon. A wizard's stronghold might house summoned guardians or magically-altered experiment creatures. Evil and desecrated shrines and tombs will likely have undead or fiends. An enclave of barbarians, elves, ogres, or orcs might still call the ruined city home. A village abandoned due to plague will be home to disease carriers. A curse upon a city may have turned its aristocracy into wererats or vampires.

I try to pick a few different monsters types - intelligent, organized monster groups with lairs and factions inside the dungeon, unintelligent scavengers and predators which roam its rooms and halls, and singular, powerful monsters with or without minions. In AD&D terms, if I'm making a 1st level dungeon, I'll want it to have a mix of 1st, 2nd, and 3rd level monsters, according to the DUNGEON RANDOM MONSTER LEVEL DETERMINATION MATRIX:

Likewise, a 16th level dungeon might include a mix of monsters from levels 1 through 10.

I might go so far as to use reaction rolls at this stage to determine who is friendly, hostile, or neutral towards the party, and which monsters are allied or at odds with one another. The Dungeon Checklist is a great resource - make sure there is fodder for the characters to kill, thinking creatures to parley with, and dangerous creatures to be avoided or carefully neutralized.

This all will give you a pretty good sketch, but dungeons aren't the kind of environment you can easily riff on using minimal information. You need to know specifics. How well-lit is it? How high are the ceilings? How many rooms are there? How many levels? How are the rooms laid out? Are they connected by passages or doors? Are the doors locked or stuck? Are they wood, stone, or metal? What's in each room? How many monsters are there? Where are the tricks and traps? How do they work? What damage do they do? What saving throw is needed? Where is the treasure hidden? How much of it is there?

As I've said, there are so many ways to determine these things that it's nearly impossible to suggest best practices. It will differ for everyone based on their taste, system of choice, and campaign setting.

One of the best tangible tips I can offer is to design dungeons in chunks. This somewhat solves the question of how many rooms and how much of each thing (empty rooms, monsters, tricks/traps, and treasure) to include. I use 20-room chunks along with the AD&D 1e dungeon stocking table:

Thus, if I have a 20-room dungeon, there are 12 empty rooms, two with monsters only, three with monsters with treasure (these are my monster "lairs" in the dungeon), one "special" room, one trick or trap room, and one treasure room (like a vault behind an especially secure or secret door). This to me is a small dungeon (boo, hiss, five-room dungeons stink). If I want a bigger one, I add 20 more rooms. If I need more, I add another 20, and so on. 

Since each 20-room chunk contains a "special" room which might also contain a stairway, I tend to include one stairway per two 20-room chunks. A level can have multiple stairways up or down, of course, so this isn't necessarily a limitation upon how large a single level can be.

If I want to create a big 100-room dungeon, I know I need 60 empty rooms, 10 rooms with just monsters, 15 monsters with lairs and treasure, 5 trapped rooms, 5 treasure rooms, and so on. 

You might use a different dungeon stocking table to inform the size of your dungeon "chunks". For example, from OSE:

Your "chunk" might be 36 rooms: 12 empty (2 with hidden treasure), 12 with monsters (6 with treasure), 6 special, and 6 trapped (2 with treasure). Once again, adjust to taste.

Empty rooms are not truly empty, but contain environmental storytelling, hints at what awaits in other rooms, time-wasting set dressing, or interactive elements which might come into play in the future, such as if a wandering monster shows up there, or if the room is restocked with a monster on a future delve. 

I like using Courtney Campbell's resource on empty rooms to determine what a room's original purpose was, and from there determine what sort of set dressing to include. I do this with rooms that are otherwise occupied as well. The 1d6+6 orcs are not just standing around in some barren chamber, but are instead in an old kitchen scavenging for food, in the wizard's bedchamber scraping the gold leaf from his headboard, or in the lounge gawking at the marble statue of a nude woman.

The specific monsters I use could be determined by rolling on AD&D's dungeon encounter tables, or I might pick a few based on the dungeon's history. Tricks, traps, and treasure would be similarly informed. An elven ruin might have more magical traps, while a dwarven one might have more traps involving shifting masonry. Gnomes use clockwork devices, kobolds use poison and pots of stinging insects, and defiled shrines are warded by curses and negative energy. Elves treasure ornately carved wooden objects, spellbooks, moonstones, and magical bows and swords, while dwarves treasure stone carvings, gemstones (but not pearls, because dwarves HATE pearls), and magical axes and hammers.

The number of monsters appearing, gameplay statistics of traps, and value of treasures will all be informed by your system of choice, of course.

As for layout, you can create your own dungeon and still steal a little bit. You could take an existing map from one module or another and simply restock it to your liking. This is useful if, for example, you know you want to run the hideout for a cult of Elemental Evil, a fire giant stronghold, or a Tomb of Horrors-type thing, and know where to find one. I ran Tomb of Annihilation's Fane of the Night Serpent, Princes of the Apocalypse's Sacred Stone Monastery, and Storm King Thunder's Forge of the Fire Giants this way, using the maps and room descriptions but changing the monsters, treasure, and mechanics of traps and the like to suit my needs, and it worked quite well.

Alternatively, you can steal a more generic map from somewhere online. I've used a lot of Dyson Logos maps in my games. I often find this unsatisfying though, as the types of dungeons I can make are limited by the maps that are available. I have to either compromise my vision to suit a map that wasn't created with that vision in mind, or find a map I like first, then come up with the vision after. Neither is ideal.

So, I often create something from scratch. I don't usually bother with detailed maps these days. I've tried using AD&D's Appendix A to randomly generate dungeons. It's really confusing and it creates a map that kind of stinks. I feel the same way about random dungeon generators found online. I've basically given up on it.

So, if a relativistic flowchart-stye map is good enough for the players, it's good enough for me! I start with a bubble in the center of the page (with stairs leading up to the surface), then roll 1d4 to determine the number of exits. For each room branching off of that, I roll d4 again to determine the total number of exits (that is, if I roll a 1, there is only one way into the room, and no other ways out). I do this until I've exhausted my 20-room chunk or end up with only dead ends (to which I might add secret doors to additional rooms to fill out any remaining rooms from my 20-room chunk). I can add additional notes as needed, like "This room is really big and takes two turns to map," or "This hallway is really long and requires a wandering monster check when passing through it."

I tend to put important rooms like monster lairs (those with treasure), "special" rooms, and treasure rooms in those areas farthest from the entrance, so that the characters will have to endure the longest route through the dungeon to reach those rooms. Rooms with only monsters or only traps will be those at important intersections or choke points, ensuring that the characters either go through them or find a long way around them.

After that, it's a matter of writing the key, which I've demonstrated in my rewriting of the room from B1, above. I like to find a middle ground between writing something descriptive but also usable at the table. Highlight interactable elements. Try to anticipate what the players will want to investigate and provide additional detail as needed. Try to think of all the information you might need. Think of what questions the players might ask, and come up with answers. Include game mechanics whenever possible to avoid looking stuff up during the session. Write it and reread it and refine it.

As you run the dungeon, it will change. Make note of which monsters have been killed, which have had changes in attitude towards the PCs, which traps have been disarmed, which treasures found, which doors unlocked, and the like. Once the players make contact with the monsters, feel free to move them around. They should be doing something, not just hanging out in one room all the time.

When the characters leave the dungeon, I like to change things. Monsters which don't like each other may come into conflict, killing or capturing one another. Those that do like each other may form alliances. Their territory may expand as the characters open doors, disarm traps, and kill other monsters. They may recover treasure themselves, find secret doors of which they were previously unaware, and update their own dungeon maps with scouting missions.

This is also when I restock the dungeon. I go through each room the characters have already explored, checking again for monsters, traps, and treasure. Perhaps a new monster has wandered into the dungeon, or wandered up or down from some other level. Perhaps a trap has been reset, or a new trap placed where there was none before. Perhaps the monsters have moved their treasure to a previously unoccupied room for safe keeping. 

This can be a boon or a bane to the players. Perhaps the friendly goblins have thwarted a counterattack from the orcs, and now the orcs are lesser in number. Perhaps the orcs triumphed and carried off the goblins, and now the characters have lost a valuable ally. The rival adventurers may have perished in their own quest, or maybe they succeeded and carried off some valuable treasure, or simply made progress and disarmed some trap. Discard any results that don't make sense, or stretch your imagination until they do. No two delves should be exactly alike.

As I've explained, this is much too large a topic to possible cover in its entirety in a single post. Hopefully, I've provided a somewhat comprehensive explanation of my approach to getting started and to doing the long, somewhat tedious work of preparing a location like this for gameplay. Everyone's process will be different. This is a only a peek into mine.