When the heroes finish clearing away the rubble they find the entrance to a long forgotten dungeon. As they enter, the stale musty smell clearly indicates that nothing has come in or out of this labyrinth for a very long time.
“Divine characters up front, everyone else get your radiant powers and glow stones ready. It won’t be long before we encounter our fist undead opponents.”
More often then not, when an adventure involves exploitation into a sealed environment, like a dungeon or tomb, the PCs expect to fight undead. And you know what; in almost every example of this scenario they’re right.
With the multitude of different undead available to choose from this still leaves DMs with a lot of creative wiggle room, ensuring that every dungeon isn’t filled with the same monsters as the one the PCs explored last week or the week before that. However, using undead again and again does introduce a whole other series of problems to your game.
The more you use undead the more you’re telegraphing your plays. The players will start gravitating towards divine classes because they know that having access to more radiant powers will give them an edge. Those not interested in playing divine character will suddenly equip themselves with weapons that can deal radiant damage. Unless you’ve intentionally designed a campaign where the heroes are undead hunters then stop throwing undead against them every time they venture into dungeons.
The key to keeping any D&D adventure fresh is to have the PCs face both new and different challenges. One of the most common criticisms about D&D Encounters: March of the Phantom Brigade was that there was too much undead. Week after week it was Phantom soldiers. Sure one week it was Phantom Armigers the next week it was Phantom Squires and the next week it was Phantom Justicars, but these monsters were all essentially built from the same template. Their powers were similar and their traits (like insubstantial) were all the same. Boring!
In the case of a completely enclosed system (like a dungeon), undead are often the only kind of monsters that really make sense. After all it’s a closed environment without any means of getting in or out. Wouldn’t any other kind of monstrous threat have starved long before the PCs should up in search of treasure? Not necessarily. This is where the DM needs to flex his creative muscles and be imaginative.
Understand the Locale
Your monster choices need to make sense based on the location. If the setting for the adventure has been sealed tightly until the PCs arrive and unseal it, then you can’t just pick random monsters to populate it. Remember that whatever monsters you do decide to use need to have a way to have stayed alive. This is the number one reason DMs will turn to undead. They don’t breathe or eat so no one ever questions finding them in a dungeon that’s been sealed tightly for a century or more. But that doesn’t mean that undead is the only choice available.
This category includes Golems, Gargoyles and Warforged. In many cases constructs are created to perform a specific task. These tasks are often dangerous, repetitive or boring. Guarding a tomb certainly falls into the dangerous and boring categories. Constructs with no intelligence will only perform the tasks they were instructed to perform. A more intelligent construct will likely have a greater purpose than just guarding a dungeon. It’s important to decide why the construct is guarding the dungeon. Is he bound by some oath or sense of loyalty? Maybe he’s trapped here, unable to find his own way out? Could he be a prisoner, too difficult to destroy, and buried forever, becoming someone else’s problem should they ever open the dungeon?
Specifically I’m thinking about Demons and Devils. Most do need sustenance, but can go very long periods without food. These creatures aren’t usually native to dungeons, so it’s important that you come up with a reason that they are there in the first place. Did a mad Wizard summon this particular Demon, binding him to a particular room or floor of the dungeon? What does the Demon need to do in order to break free? Knowing and understanding the monster’s motivation will help you come up with good tactics when using it in combat.
Elementals are an excellent choice for populating a completely sealed environment. They don’t eat, breathe or age. They are usually creatures of pure instinct. With the exception of fire elementals, earth, air and water elementals can easily be tied to just about any area of the dungeon without arousing the PCs’ suspicion. Elementals also have the added bonus of not caring about treasure. Where a Demon or a Warforged might use a magic sword against the party, elementals certainly would not.
Not Quite a Closed Environment
Even with the suggestions presented above, there are other plausible ways come up with monsters to populate dungeons that are completely closed off. You can always cheat a little bit and open the closed systems just a little bit. Not enough that the PCs would have to worry about monsters coming and going or other explorers having beat them to the treasures contained with, but enough to present a few unexpected foes along the way to finding said treasure.
By introducing a small crack or hole somewhere in the closed dungeon, creatures that can get through these tight spaces can suddenly become a part of your potential monster roster. We’re not talking about a hole big enough to get a suit of magical plate armor through, just large enough to allow air or water in. This doesn’t give you hundreds of new monsters to choose from, but it will give you something different and more importantly it will give you options that the PCs won’t expect.
As soon as you’ve got cracks, you’ve got the potential for a shapeless creature. Oozes are a staple of closed dungeons. It’s unlikely that the dungeon’s original inhabitants had a bunch of Gelatinous Cubes or Ochre Jellies roaming around, but if there are cracks in the dungeon then this is a good explanation for how they’ve shown up since then. Almost as overused as undead, oozes should be used sparingly.
A long, narrow hole that looks into a room might grant line of sight for a teleporting creature. Maybe a band of Eladrin mercenaries are using this tomb as a hide out? They can teleport into the only room they can see, making it an excellent base of operations. However, they can’t open the door and get into any other parts of the sealed system. Imagine their surprise when the PCs come crashing through the door. The Eladrin can try to flee by peering through the tiny hole and teleporting away (something they’d have to do one at a time) but they’d leave behind all of their ill gotten gains. Now this is an interesting fight that no one expected.
Magical portals may seem like a cheat, but if you work very specific conditions and rules into their mechanics then they can be used to bring in whatever kind of monster you want. The best way to use these in a completely sealed environment is to tie it into a trap. Perhaps a chamber has a summoning trap that will activate when someone enters without speaking the password? This is plausible and could very well still be active after decades or centuries. If the PCs are the first ones through then suddenly they’ve got to face off against a Beholder or some other monster that wouldn’t have otherwise been able to survive in the dungeon all that time.
The easiest cheat I’ve used to populate a closed dungeon with monsters is to introduce an underwater steam or other water source. Accessing the dungeon via the water is not something that adventurers or treasure hunters could ever do without extensive preparation, foreknowledge and magical assistance. The underwater stream does make it possible for creatures that can breathe both water and air to be in at least part of the dungeon. Much like the Eladrin example above, the creatures could be limited just to those rooms or areas that are accessible by the water. As in the above examples, the PCs are likely to be shocked to find Kuo-Toa or Bullywugs inhabiting four rooms on the lower level of what they believed to be a dungeon that’s been sealed for a century.
Embrace the Unconventional
The next time you’re creating a dungeon, tomb or other completely enclosed environment for your PCs to explore, don’t immediately choose undead to populate rooms and threaten the PCs. There are plenty of other, viable and sensible alternatives as we’ve presented here (and this is by no means an exhaustive list). That’s not to say that you should completely abandon undead altogether. A good battle against a skeleton mob is a lot of fun and lets divine characters show how awesome they are when fighting undead. Just be aware of the alternatives and be sure to use them. You’ll likely have a lot more fun creating and running the adventure and your players will be happy that they’re not facing undead for the hundredth time.
What alternatives to undead have you used when populating a closed off dungeon?