The Campaign Builder's Guild

It seems to be a law of nature that every fantasy world must have vast, subterranean cavern complexes which are all somehow connected with each other and house terrible monsters and strange civilizations.

I've started on my own version for Urbis - which I have called "Terra Profunda" (I didn't want to recycle "Underdark" and "Underworld" was already used for a different concept within the setting), and I could use some more inspiration.

So, what is the Underdark like in your setting?

[This relates to my Necropact setting, of course.]

I actually hadn't give much thought about an underdark in my setting at all. There would be plenty of caves and whatnot but I don't see any connection between them. Of course, with this setting I want to avoid the normal stuff.

Quote from: Ninja D!Of course, with this setting I want to avoid the normal stuff.

So do I - which is why I actually came up with an explanation for all those tunnels. See [link=http://urbis.wikidot.com/fire-worm]this entry[/url] for details.

My present campaign world doesn't have an Underdark, though there are a few very large limestone cave systems that are inhabited.  It's more of an earth-like situation, and there aren't massive city-sized caverns or huge underground seas like there are in the classic FR underdark, and the cave complexes aren't all linked together.  The creatures that do live there are not "civilized," and don't have cities or agriculture or other such things.

One of my previous campaign settings (that I've actually run games in before), however, was disk-shaped, with either side of the disk inhabited and the interior of the disk one enormous cave system called the "Inner Realm," which easily had more space in it than both surfaces combined.  The only way to travel from one side to the other was to go through it, essentially "digging to China" and coming out on the other side.  That was a lot more classically Underdark-ish, with entire underground kingdoms and such.

I find that the setting above ground often dictates the setting below ground.  Having huge FR-style underground realms just seem to work better in certain environments than others, depending on whether the designer is going for a more pronounced, high fantasy or a lower, more nuanced fantasy setting.  I've designed both and played both and it's just a matter of what works best with the rest of the material.

My campaign setting is almost entirely underground. The surface is to dangerous for most lifeforms. Originally it didn't have too many underground caverns, but as the surface became increasingly dangerous more and more creatures moved underground and expanded the caves. Over the course of hundreds of years the tunnels and caves were connected. Of course they aren't all connected but there are many large complexes and megacaves.

Eschaton takes place on Earth, so it's got the same caves and stuff. No underdark.

While some of my earlier Avayevnon stuff made reference to what was essentially an Underdark, it never got focussed on, and may not be relevant in the current incarnation.  There's a good chance it will be removed.

Underground? Yes.  Tunnels?  Of course.  In fact, I have figured at least in passing that there would be numerous underground trade routes established by Issachar, but probably not a totally interconnected Underdark system.

I haven't yet decided how much the subterranean should feature in the Savage Age. I'm almost 100% sure that there won't be anything like a global cavern network, though. I'm tempted to go for a more mythical Underworld feel, with a blurred line between actual caves beneath the common soil on the one hand and a kind of metaphysical "plane" on the other.

Basically, as my planet is larger than real earth, it has a vast underdark that streches down almost 30 miles total, through it varies in deta, only half of which cna substane human life.  Near the surface we have tings like real life caves and what not, but the offical underdark starts about a mile down.  Near the top you have humanoid cities, and ancient civilations (drow, deep dwarves, deep gnomes ect), but as you get further down the populations decrease, until eventually it becomes inhabeted by only ancient evils long forgotten.  When you thing you've reach as far down as you can go,  you might find that you've in fact reached a new plan located at the bottom, an entire new realm run by the gods of the underground.  There.....well you don't want to go there.  
from
EE

Karros doesn't have an underdark, though it does of course have cave systems. These though don't connect to form a massive singular underdark.

Like many of the posters above, my primary setting doesn't have an underdark per se.  It does have large subterranean cave/tunnel networks.  Most of these are the vast, scum-slathered undercities of the seven Twilight Cities - sewers, old streets, ruins, caverns, catacombs, etc, all blending into one another.  I'm trying to give each undercity a very distinctive flavor tied to the city above it, so the undercity of Lophius is a barnacle-encrusted cave complex merging with flooded ruins, whereas the undercity of Baranauskas is a Gothic stony labyrinth, a jumble of baroque tombs and brickwork sewers.  The other major subterranean edifices of the world are going to be the underground cities of the defunct Cestoid Imperium in places like the Chelicerae Mountains - huge, vaguely non-Euclidean or Lovecraftian structures built by intelligent centipede/tapeworm people.  I want a very R'lyeh feel to these, a very warped, surreal texture - if Skein's organic towers resemble a Gigeresque biomechanoid landscape, I want the abandoned cities of the cestoids to look like Ernst's  Silence or Europe After the Rain.

I now have a question that stems from the responses in this thread; If your setting has no "underdark", why not?

Quote from: Ninja D!I now have a question that stems from the responses in this thread; If your setting has no "underdark", why not?

Er, why would we?

It seems like an exotic element that fits well in certain settings, more like flying islands or underwater cities, not something inherently necessary to all fantasy.

For myself, because I'm mostly working with historical fantasy, I try to avoid diverging too much from the real world. I could forsee other worlds--and have had them in the past--where such a conceit is appropriate. But I see those more as the exception.

Memory Fading has no underdark.  There are two large underground cities, about one hundred miles apart, that one can travel between if needed - other than that, just regular ol' caves, caverns, and chasms.

My setting mostly has natural caves, But the Maze Mountains are a huge mountain range that had been turned into a fortress even before humans first set foot on the planet. Now it is riddled with several thousand miles of corridors, casemattes, bunkers, arcane technological devices and gun emplacements, all partially destroyed, abandoned and decyaing. Most of the stuff the humans built is above sea level and inside the mountains, but below sea level, natural and huge artificial caves and thousands of years old fortifications stretch almost five miles down into the crust. Some of these caves are overgrown with fungi and inhabitated by huge spider-like creatures, others have abandoned cities or fortresses made from something that looks like smooth, black resin inside.
in the deepest levels, the original inhabitants still live. For a certain value of "living".