#underchasm

First of all, I am SO sorry this is so late like I read this early in the morning before work and then told myself i’d answer when I got home. But boom, weeks later and here we are. I am The Worst and I apologize but IM HERE NOW. Since I waited so long, i’m gonna go all out for you anon. So prepare for a long answer!

The Underdark is a complicated setting that I was first introduced to through the first few episodes of Critical Role season 1! On the wikipedia, it says:

“It is described as a vast subterranean network of interconnected caverns and tunnels, stretching beneath entire continents and forming an underworld for surface settings.”

Some consider it to be apart of the prime material plane (the normal world), and others consider it a realm in and of itself. You can see it primarily in the Forgotten Realms and World of Greyhawk campaign settings. Hell, its even in the video game, Neverwinter Nights! So we know it’s popular. But what is it?

Well that’s honestly up to much interpretation. The Underdark can be what you want it to be. But there are some shining features of the Underdark that make it what it is:

Its underground

It’s dark, it’s dank, and it’s cold

Usually inhabitted by grotesque monsters and uncommon races such as drow, illithids, aboleth, duergar, kuo-toa, ect.

Much of those who inhabit the Underdark are (in past official campaign settings at least) of neutral to evil alignments. This is optional though imo.

There’s usually an entrance or portal into the Underdark somewhere on the surface or in the prime material plane. That part is up to you to create.

In my homebrew campaign, the entrance to the Underdark is through a massive, inactive, hollowed out volcano in which the drow of my continent reside within. In the Forgotten Realms setting, there are ports to the Underdark via the Underchasm which is a huge canyon created by a spellplague. Seen here:

But you can make your port of entrance anything you want it to be! That’s the fun part.

Moving on, I like to reference the level-system used in the Forgotten Realms (because while most like to shit on it, i think it’s a very well developed campaign setting OKAY don’t hate me) to describe the Underdark’s specific chasms and their purpose and what they hold.

Upperdark

The first three miles below the surface. It was here where the surface dwellers and those in the Underdark most often met. 

Middledark

Located three to ten miles below the surface, this layer was where most of the Underdark cities were located. 

Lowerdark

Ten miles or more below the surface, the Lowerdark was where even those who knew the Underdark were loath to go.

So it’s obvious that the Underdark is more than just a dark, dank hole in the ground of someone’s campaign setting. As described above, there are settlements too! Thus, the presence of an economy as well. Typically, an Underdark economy will consist of armor, timber and weapons, as well as the darker trades such as slavery, magics, and exotic goods.

But usually, there isn’t just one massive, all hailing economy in the whole of the Underdark. The Underdark is a huge place, typically encompassing entire continents or entire planets. It is often a lawless place in most settings, so economies and rules of the land can vary from city to city, state to state, continent to continent. It is entirely up to you how you want to split up your Underdark setting or how you’d like to civilize it.

Personally, i’d love to see a unique take on the Underdark where they’re not the dark, horrific place that everyone views them to be. But instead, they’re a civilized society with some rather dark leaning practices. But that’s just me.

Just keep in mind that because the Underdark setting is usually so massive, you shouldn’t feel the need to develop the entire thing. It’s like creating an entirely new world in most cases, and I highly doubt your players who live in the prime or the surface will find the time to explore all of it. That is unless your campaign setting IS the Underdark. Then, by all means– GO NUTS!

All in all, the Underdark has a few iconic and unique characteristics that should probably be met so it’s recognized as the Underdark. But for the most part, it is still entirely up to you how you brew it up! That’s the great thing about Dungeons & Dragons, is you can rip all the pieces of something you like from different settings and paste it all together to create something new and unique, never before seen! So good luck in your Underdark makings! And if you have any other questions, do let me know! I’ll try my best to be on time this time lmao.

In the Fold, where the Teeth of the North abruptly switch directions, is located the River of the Dark. This river is so named because it emerges from a series of deep underground caverns that are infamously mazelike and complex. This has made it a perfect hiding place across history.

Its first notable inhabitants were a group of hermit Khul. They were primarily responsible for mapping and clearing the River Caverns. Eventually, they died off or were driven out, and the caverns were later retaken by a number of Faen refugees fleeing persecution. Over time, the caverns were expanded, with groups slowly digging out new tunnels or expanding existing rooms, until the underground installation could hold a thousand people and supplies easily.

The base never saw widespread knowledge. With brief periods of use combined with gaps of multiple centuries between usages (a result of safety concerns about it not being hidden), the base remained either unknown or believed empty.

The most significant of all the occupations the base saw was that of the Alterran Flame. They were able to create entirely new wings and a second entrance at the end of the Valley of the Fold. It was also discovered that the deeper sections of the River Caverns, far down and deep into the mountains, intersected the Underchasm, which made the location even more valuable.

The Flame also made the base much more secure, given the great opposition it faced. The entrances were properly gated and hidden, and the mountains of the Fold were tunnelled through and mounted with turrets. A teleportation system, built by Lunara, became the new access method. Traps were built, most notably a set of new tunnels and a reservoir at the River of the Dark's beginning. The intent was for the River, the Underchasm security tunnels, or the base itself to be floodable if necessary. Guard positions were also stationed along the two "front" entrances. Lastly, if it was discovered that the base was occupied again, there was a plan to give the impression that it was simply an Izemin heritage site (based on the previous use).

These teams performed many functions- setting up strings of mechanical lights, repairing damaged sections of pathways or bridges, responding to earthquakes in particularly volatile regions like northern Ushern and the Polar Loop, and creating exit tunnels when there were no natural ones nearby (and adding whatever security measures were necessary, like airlocks on undersea exits). When a section of the Underchasm was deemed impassable- like the physically obstructed Eternal City branch, the magically obstructed sub-branch in Arkana's Machine, or the monster- filled area passing through the deep Mouth of Urias- the Underchasm teams worked to provide alternate routes around or above the problem.

These teams worked hard because they recognized the potential of the Underchasm as a transportation system- it allowed the crossing of towering mountains and deep oceans on foot. As it happened, this potential was rarely used by large groups, owing to the risk of the Void, simple lack of knowledge that the Underchasm existed or that it was so immense, and the speed of other transportation methods. The Underchasm instead saw more use by small travelling parties willing to take shortcuts through harsh mountains, messengers with secret deliveries, or adventure seekers looking for long, risky hikes across great distances.