Caves have been one of the ‘go to’ dungeons since the earliest days of Dungeons & Dragons, and some of the most famous dungeons in the game are caves. If you play through the D&D starter set, Lost Mine of Phandelver, the first and last adventure are both caves. They’re iconic. So why don’t they feel quite right to me?
When I think of real-life caves, I think of cold, dark, damp, narrow spaces: the sort of places where you might marvel at what you find underground, but you’re also very relieved to see the light of day when you come out the other side. If we lived in a fantasy world, I definitely wouldn’t go down a cave unless I had to.
I tweeted this week that caves in D&D don’t feel creepy or perilous enough, and it seemed to be a thought that chimed with a few people. So, in this post, I’m going to offer a few ways we can make caves more atmospheric and more dangerous using existing rules.
(A couple of quick notes. Firstly, I am not talking about the Underdark in this post; that is a whole other thing, in my opinion. Secondly, I am in no way a cave expert, so if you are, feel free to correct me in the comments.)
1. Use darkvision properly
This is my number one tip. Lots of people don’t run darkvision as written, and in doing so they risk making it more powerful than it is meant to be. Darkness is still shadowy in darkvision; if you don’t have a light source, you have disadvantage on Wisdom (Perception) checks, and this is the equivalent of a −5 on Passive Perception.
This is not a small thing. It means that without a light source, creatures can sneak up on the party without being especially stealthy.
Grimlocks are perhaps my favourite example of this rule in play. Without a light source, a grimlock has an effective Stealth score of 18: +3 from Dex and proficiency and a further +5 from its stone camouflage feature. A character without a light source relying on darkvision alone would need a passive Perception of 23 in order to avoid being surprised – or, to put it another way, a Wisdom (Perception) check of +13. (If the idea of grimlocks sneaking up on the party sounds like an excellent adventure to you, pick up my adventure at the DMs Guild! Pay What You Want for this week!)
2. Use pointcrawls, not maps
I’m a big fan of pointcrawls, especially at higher levels when there are so many ways for adventurers to completely bypass a dungeon complex. And actually, when you look at real-life cave maps, what do they look like? Pointcrawls!
Pointcrawls work well as a structure for caves because they put the focus on the tunnels rather than the chambers. There might not even be any chambers, or if there are, perhaps they are very small. In most dungeons, corridors are mainly a way of getting from A to B; you don’t necessarily expect traps or encounters. In a cave, the tunnels are the dungeon, and the connecting chambers are occasional respites.
Pointcrawls are more of a schematic than a map, in much the same way that the London Underground map is not a real measure of the length and shape of the Tube. This might be a bit less evocative, but it also gives the DM more narrative freedom to focus on the journey through the tunnels.
3. Add height
Another problem with lots of D&D cave maps is they are essentially 2D. From above, they don’t look much different from constructed dungeons like the halls of Undermountain or the towers of Castle Ravenloft. In real-life caves, you don’t expect a smooth, flat corridor between chambers; there may be slopes, drops, uneven ground, or rocks to clamber over.
In game terms, add some Athletics checks, Dex saves. Use difficult terrain. Include the risk of fall damage. Give the players a sense that moving through the caves is an obstacle in itself.
4. Squeeze!
It is a running joke in my group that the most dangerous adversary in 5th edition D&D is a 5ft-wide corridor. Rules as written, you can move through a hostile creature’s space only if the creature is at least two sizes larger or smaller than you, and even then it’s difficult terrain. If a space is smaller than the creature, squeezing rules come into play (see p 192 of the Player’s Handbook).
Combat in D&D often assumes a reasonably large space where ranged characters can shoot longbows, spellcasters can throw fire bolts, and fighters hold the front line. It’s fun, balanced, easy even. Now imagine a network of claustrophobically tight tunnels where ranged combat is impossible and even hand-to-hand fighting is a challenge. I bet even high-level characters would find this difficult.
One other thing about narrow tunnels: it balances out the benefits of having darkvision. If your caves are vast open spaces, the ability to see 60 ft in the dark is clearly very powerful. But if most of the cave is a narrow, winding tunnel, even a drow is only going to be able to see a few feet in front of them.
5. No resting
This one is perhaps the most controversial as it’s not technically ‘rules as written’. However, I strongly believe that DMs should have some say as to whether it’s appropriate for the adventuring party to take a long rest, not least because it helps control the pacing of the game. (I’m in good company here: Sly Flourish argues that the easiest way to manage rests is to let the story dictate when and where rests take place.)
If you are running caves as a series of tight, narrow, treacherous spaces, resting shouldn’t be easy. In fact, it might even be impossible. Talk this through with the players so they know what to expect, and if you think it’s just going to make the adventure a slog, go with your gut, but removing (or limiting) the chance for rests is certainly going to change the rhythm of the adventure.
How do you make caves fun? Let me know in the comments below.
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