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.