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Nerdarchy > Dungeons & Dragons  > D&D Ideas — Underdark

D&D Ideas — Underdark

Welcome once again to the weekly Nerdarchy Newsletter. This week’s topic is the Underdark. By this time normally we would have done our live chat and started the discussion there on YouTube, but unfortunately YouTube live was down at the time and we weren’t able to stream. We were back the following Tuesday June 17 at 8 p.m. eastern time to talk about heroism.

In case you missed it here are this week’s videos

Delving Dave’s Dungeon

The Underdark is one of the most dangerous environments in a D&D campaign. Long-forgotten evils lurk beneath the surface of the world. Things that can’t survive the light of day go there to fester and grow.
One of the more fun D&D campaigns I’ve run on the Nerdarchy YouTube Channel was our Outkast game. It was an urban D&D game that took place in an Underdark city. Unfortunately the game fizzled out.
The thing to remember about the Underdark is the environment can be just as varied as the surface world. You can have lakes, oceans, rivers, islands, fungal forests, crystal plains, and so much more. Here is a piece I wrote back in 2014 with just a snippet about the Underdark.

Tricky Dungeons and Dragons Terrain — Goo-Blythe’s Guide to Surviving the Underdark

“Youses sure about this tall one? Underdark very dangerous place,” whines Goo-Blythe.
“I’m sorry, Goo-Blythe. Time is of the essence if we are going to reach the Lady Lureanna in time to save her,” said Sir Gregory.
“Yes, yes, I understand, but must you bring those lights with us?” quietly whines the goblin Goo-Blythe some more.
Dungeons & Dragons Terrain — The Underdark presents many natural challenges
First and foremost light is most likely to be the first obstacle to overcome. Light represents a dual problem in the Underdark. One, you need to have enough light to last the duration of your journey through the underground realms. Second, most things living in subterranean environments don’t need light to see. Therefore, above worlders traipsing around with torches, lanterns, or light magic stand out. Depending on which game you are playing  — Pathfinder RPG, one of the Dungeons & Dragons editions, or some other RPG system, having light might be no problem at all.
So you are only left with the problem of being a beacon to hostile subterranean creatures.
“Halt tall one!” growls Goo-blythe as he flings his arm out in front of Sir Gregory, stopping him in his tracks. Pointing at the ground at the tall human’s feet with his dagger the goblin whispers “close.”
“What?” Sir Gregory asks. With a sudden movement the little goblin slams the hilt of his dagger down in front of the knight’s feet. Instantly the stony ground begins to crumble and fall away into the darkness.
An area just under Sir Gregory’s toes extending out in a 12 ft. arc is just gone. In a whisper the goblin utters “Gultch.”
Stomping up from the rear in a huff, Morian Bloodhammer the dwarven warrior grumbles “What’s the hold up, sneak?” Looking down, “Oh, shatter stone! Nasty stuff.” Looking around further and grunting to himself. “A whole field of the blighted stuff. A bad omen for sure. Told you bringing the sneak would bad luck.”
“Well if not for Goo-Blythe I’d be swimming through the darkness below. So I say he’s good luck,” proclaims the knight.
Dungeons and Dragons Terrain — It’s not just the monsters that will kill you
There are many natural hazards in the Underdark. These can range from the shatter stone described above, rock slides, poisonous gasses, combustible gasses, fast flowing rivers, vast lakes, scalding hot springs and steam vents, lava lakes or rivers, and many other real world, not to mention fantasy world hazards.
“What is that up ahead?” asks Sir Gregory as he points at an eerie green glow shining down the tunnel.
“Loomoss,” answers the little goblin.
“Do we have anything to fear from it?”
“Only if you be scared o’ plants and lichens,” booms the dwarf.
“Not from the loomoss,” snickers the goblin. “But waits. There are things that like to eats the stuff and whenever things come to eats nastier things will come to eats them.”
As the group comes to the opening of a cavern the little goblin points up at the ceiling.
”Look see the dark spot there. Cave fisher. If we try to just cross it’ll go after anyone in the rear and drag it up there for it’s dinner.”
Dungeons and Dragons Terrain — Even the safe places can be lethal underground
Places that aren’t themselves dangerous present hazards and risks, because predators know prey will be drawn to these spots. Anywhere that can provide water or food is likely going to be hunting grounds for one nasty critter or another.
“Hmmm…” mutters the goblin, taking a closer look.
“What is it sneak?” spits the dwarf.
“The loomoss — looks hows it grows. Someones does it on purpose. And there!” Goo-Blythe points to a skull from a goat under the spot on the ceiling he pointed out earlier. “Someones feeds its.” Sir Gregory
“Is this going to be a problem?” Sir Gregory asks. The goblin and dwarf respond in unison.
“Depends on who’s feeding the cave fisher and growing the loomoss garden.”
Dungeons and Dragons Terrain — Roleplaying can even happen in the under realms
Many intelligent creatures inhabit the Underdark and not all of them want to kill you. So there are plenty of opportunities to have nonviolent encounters and possibly make new and interesting friends.
D&D ideas Underdark Descent into the Depths of the Earth

Descent into the Depths of the Earth set off a series of adventures leading to the introduction of the Underdark to D&D. [Art by Jim Roslof]

From Ted’s Head

Traveling the Underdark, or the Beneath over here at Nerdarchy, is dangerous. So as the trusty wise one tells us take this with you. I have made a few magical items that will make traveling the Underdark just a little bit safer. Mingel the deep gnome knows the surface dwellers die more often than not when going into the deep reaches of the Underdark. His first item is to help travelers from getting lost in the winding caverns and tunnels deep underground.

Mingel’s Map of Movement Memory

Wondrous item, rare
This large scroll of sturdy parchment is quite intelligent. It has the ability to track all the places you go underground. Everything you encounter as you walk and observe it is able to record in detail, with annotations should you speak them to the map, as you travel. There is a blinking dot that is always easy to spot to identify where you are on the map. Having such a map, you can easily backtrack your trail when you make a wrong turn or even take you back to the nearest safe location.
This is unlike other maps because once obtained it only has the room you are in and it begins recording from there. Hopefully you find or acquire your copy in a city so you can travel back to that location. It then records the detail as you move along your trail.
The stories go there are a few maps that do not reset upon going to a new owner though those would be very rare indeed. These maps have notations from various users and the scrolls would be very large, ever expanding to all the new locations recorded.
The maps do have one very large drawback. These maps are made with Underdark magic and material. If they are exposed to direct sunlight for even just a few minutes they burn up and are destroyed. But worry not. Travel back to the wonderful deep gnome city and acquire another.
Mingel made some other fun items to help travels as well. Getting lost is only one worry. The next issue that many travelers face is eating the wrong thing. So without further ado…

Mingel’s Food Filibuster

Wondrous item, uncommon

At first glance you think the shopkeep is trying to get one over on you as it looks just like a simple rock, but it is very special. If held in your hand while you attempt to eat, this rock will alert you if the item is safe to eat or drink. If the object is safe to consume it will deliver a soft, warm sensation. If the food or drink would be poisonous or cause a disease or be harmful in any way it will deliver an unpleasant shock. It is not enough to cause any damage but certainly enough to alert you the course of action is unwise. What you do thereafter is entirely up to you, as Mingel would say.
Lastly there is the very real fear of way too many things underground that either want to kill you for food, for sport or just because they feel like. What is a poor gnome to do? Outwit them of course. Or at least that is what Mingel would try to do. But with what?

Mingel’s Rotund Rocks of Repelling

Wondrous item, uncommon, consumable

These rocks resemble eggs just a bit bigger than chicken eggs and have scratches all over them. When hurled at the ground it creates the illusion of some random creature that makes a lot of noise and goes off running down a corridor. The illusion travels for 1d4+1 minutes and even reacts and interacts with other creatures it sees. It has a passive Perception of 12, and creatures must succeed on a DC 15 Wisdom (Perception) check to see through the illusion.
The idea of these objects is you can either chase creatures away or have them chase the illusion and sound instead of you.
So there you have it. Mingel was a great wizard and who knows maybe you will see more things that Mingel made later on.

From the Nerditor’s Desk

There’s a good reason folks like Matt Colville consider the Underdark as another dimension in their games. Nerdarchy calls ours the Beneath. In Eberron it’s called Khyber. The Underdark is not any old cave system. Tunnels and caverns within a mountainside where bears or even dragons lair aren’t the Underdark.
As frightening as those lairs might be, it’s the world even deeper where the Underdark truly begins. D&D players have been fascinated by this bizarre subterranean world for decades. Many beloved adventures have pulled heroes deep into the ground, from the classic D Series where the Underdark was introduced, right up to Out of the Abyss. If you’re looking for D&D adventures set in the Underdark, check out Adventure Lookup. There’s currently 70 adventures there with Underdark as the listed environment. There’s also some material in Sword Coast Adventurers’s Guide about the Underdark.
For my money, one of the best resources to help a Dungeon Master run a D&D game in the Underdark is Out of the Abyss. On its face this is a great adventure. It begins with an easy premise and continues with a harrowing journey of survival in the endless maze of passageways and caverns miles below the surface world.
A big chunk of this adventure, designed to take characters from 1-15 level, focuses on my favorite pillar of D&D play — exploration. Running Out of the Abyss, or any adventure in the Underdark, is a perfect opportunity to describe this bizarre world and the dangers of simply moving through it to give characters incredible opportunities to explore and survive the environment.
“The Underdark is a subterranean wonderland, a vast and twisted labyrinth where fear reigns. It is the home of horrific monsters that have never seen the light of day. It is here that the dark elf Gromph Baenre, Archmage of Menzoberranzan, casts a foul spell meant to ignite a magical energy that suffuses the Underdark and tears open portals to the demonic Abyss. What steps through surprises even him, and from that moment on, the insanity that pervades the Underdark escalates and threatens to shake the Forgotten Realms to its foundations. Stop the madness before it consumes you!”
Imagine a character from an inland empire, never having seen the sea, embarking on an ocean voyage or a trip beneath the waves in an adventure like Ghosts of Saltmarsh. Or even a character born and raised in a desert, dropped into a primeval forest. Or someone from a temperate climate struggling against the elements in an arctic setting.
The Underdark is the same way — an environment that might be natural (for the most part) but so different from anything known that existing there at all is a triumph. It’s pitch black, with scant resources and perilous surroundings to navigate, populated by some of the most feared creatures in all of D&D. Mind flayers and drow live in vast cities deep beneath the ground, and terrifying threats like purple worms will make a snack out of any creatures skulking about their subterranean home.
Out of the Abyss details a lot about how to handle Underdark excursions, and with all encounter potentials along the way makes for an excellent resource for any DM interested in the Underdark. I’ve never actually played or ran this adventure, but I have plundered it many times and used several of the encounters in other games. The Oozing Temple is a particular favorite.
If you’re not into the idea of starting a campaign in the Underdark and spending the rest of the campaign following the adventurers’ quest to escape to the surface, we’ve got you covered there too. Roper Wrangler is a pay-what-you-want encounter we created based on our Monster BFF video series. We paired up a fomorian and a roper in an unusual relationship benefitting the both of them, as well as the many patrons of the Grey Gauntlet. This Underdark establishment is home of the Piercer Pacer — a deadly competition meant to entertain patrons while feeding the offspring of the fomorian’s pet roper.
It doesn’t take a trip to a strange, dangerous world Beneath to focus on exploration in your D&D games…but it’s a fantastic way to do so! There’s a reason the Underdark is an option for a ranger’s Natural Explorer and druid’s Circle of the Land. These choices can say a lot about a character, and lend themselves to memorable experiences in the dark, deadly world of the Underdark.
Until next time, stay nerdy!
— Nerdarchy Team


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