Populating the mega-dungeon part one: Mix, match and batch

Early era dungeon ecology

Populating a dungeon is always a challenge. You need to keep things varied and unpredictable, yet provide a believable environment so players can suspend disbelief. 

Balancing all the elements perfectly isn’t easy. 

As they say, the no plan survives contact with the enemy (or in this case, the players). 

Sometimes it takes a couple play throughs to find all the weak points in the dungeon’s design. Players being imaginative and innovative, it may require more. 

Many, many more. 

Mix it up

Generally speaking, I like to populate a small cluster of interconnected rooms with a sapient species like kobolds, orcs, or goblins, have an empty room arround the edges, and then populate a non-sentient monster. The sapient monsters are the dungeon population hubs; they organize regions and monopolize turf. They typically won’t tolerate anything right next to them, so there will be a buffer between them and the rest of the denizens. You can put traps or other items of interest in such rooms (such as heads on pikes, warning messages, refuse dumps, scat, stationary monsters, etcetera). 

A sapient species will have a safe and secure water source within their territory. No one wants to risk death at the hands of innumerable dungeon horrors every time they want a drink of water. Water is essential for cooking as well. If they don’t, make it an adventure point: have multiple factions fighting for control over a water source. Gold is all well and good, but you can’t drink it. 

Food and water and safety are existential issues. 

The rest of the dungeon will be a chaotic space. Large and powerful predators will have both a lair and a hunting range. Anything near their lair will be a smaller monster, one capable of evading it, whether by hiding in holes in the walls (like giant rats or ants), in the rafters above, or by some other means. Perhaps it is inedible, like skeletons, golem, living statues or elementals. 

The options are as endless as your imagination!

And if you need help making mix-matched monsters, books are just a click and a few bucks away!

Tear down those doors, Mr. Gorbachev! 

A lot of monsters have no hands. There’s just no way they can open heavy dungeon doors. So if you want wandering monsters, the critters need to be able to move freely through the common areas. The bigger the monster, the bigger the hunting range they need to reach their daily calorie count. They can’t be impeded by locked doors. 

As such, you want the majority of the dungeon halls to be interconnected and unobstructed. 

I try to take this into account, but sometimes I wind up putting a door where I shouldn’t. So long as the logic generally holds, players won’t notice a few gaffes.

I do like a good dungeon wall

Tribal monopolies 

Let’s say a tribe of orcs has settled down in a dungeon quarter. Players can expect to fight room after room of, well… orcs. Everything else will have been cleared out by the orcs, who will work to secure their turf. They’ll then install barricades, traps, and sentry posts around the periphery. Hence, you meet only that kind of monster in their lair. 

This, however, breaks the rule of keeping things varied. 

You can mix things up by varying the orcs, and throw in some shamans. Shamans suggests evil gods, so you can add a demon haunted altar. Maybe they worship a snake god, and there are snakes slithering around all over. Or they have a spider hatchery, and train the eight legged horrors as guards. Or they might have attack dogs. Kobolds might raise centipedes; the shaman could initiate new warriors by letting centipedes bite them, bestowing immunity to their poison. When they go hunting, they do so with a horde of centipedes. 

Stationary monsters with limited reach, like violet fungus, brown mould, and tentacled horrors in deep dark wells work well. The orcs will know to give these areas a wide berth, but intruders won’t. 

Prisoners that are actually dopplegangers, cunning gnome thieves, or rich potential patrons can add spice. 

Tie them in to the character back story when you're able.

"Oh crap, it's my Aunt Ethel!"

Double them up

To make encounters more interesting, combine two very different monsters into a complimentary threat. Put a brawler type with a spell caster, missile troops with brawlers. Have the goblins travel with giant spiders, kobolds with their pet basilisk, orcs in service to a necromancer, blind grimlocks with a medusa, bandits with dire wolves, ghouls with bat swarms, and so on. Think about monster relationships: where might they be complimentary? Goblins have hands and can open doors, spiders can’t, for example. Skeletons can be paired with gelatinous cubes and green slime. 

A semi-symbiotic relationship

Dungeon Diplomacy

Sapient factions will naturally compete with each other, and to compete more effectively and dominate their enemies, they will form alliances. Counter alliances will form to resist and disrupt potential hegemons. 

When the characters arrive, the most interesting situation to find is a precarious balance of power, with two or more factions deadlocked. 

The players then become the tie breaker, and they can play the factions against each other for their own benefit. By allying with one group or another, clever players can clear out the dungeon without having to do all the heavy lifting. 

You don’t want to make this easy for the players, but you do want to reward clever game play. Whenever there’s more than one faction in the dungeon, work out their political relationship, and one or two incidents that have occurred between them to cause bad blood. Maybe the kobolds sacrificed the goblin queen to their dragon-god, or the goblin tribe is composed of former slaves of the bugbears, or ruthless dwarves. Invasive troglodytes might be eating up the dungeon food supply that the goblins were carefully managing. A basilisk might be turning all the feral pigs, the food supply, to stone. 

"You have no respect for the dungeon ecosystem!"

Delicious in Dungeon

If you haven’t seen the show, give it a watch, it’s a hoot. The creator of the original manga was very careful in working out an ecosystem and food chain within his dungeon spaces. I’ve always struggled with how so many monsters can be in close proximity without food sources, unless they are eating each other. 

I added feral albino displacer pigs to the Druidun dungeon, along with thick moulds (with various side effect bonuses) eaten by hideous, poisonous centipedes, and hairless dungeon blink bunnies. All three breed fast, and act as food sources. 

Fungus is always great, and I put it all over. Easily recognizable types have a variety of effects: some emit knockout spores, and then grow on the slumbering bodies. Others give immunity to poison, or greater magic resistance, or even a few puffs of heartburn fire breath. 

Underground lakes can teem with translucent fish. Magic spheres allow trees and plants to grow. 

Centipedes eat the fungus, giant rats eat the centipedes, goblins eat the rats, grick eat the goblins, carrion crawlers eat what’s left. Boom! Food chain. Let the players come across a few incidents of it in progress and you’ve established a plausible ecosystem in their minds. 

Delightfully yum