Weird Fantasy Megadungeon

I recently added a megadungeon to my campaign but it isn't in the campaign world itself.  It is in the plane of limbo.  It is an abandoned city of a species that had created a number of portals throughout the multiverse to various planets and places of power.  Actually, abandoned isn't the right word.  The beings that built it were wiped out in a genocide perpetrated by their slaves. They travelled the planes taking slaves and gold and magic items and then retreated back through their portals when the going got rough.  They were more or less Melnibonians.  The slaves eventually revolted and wiped out their masters entire race.  They collected all the loot and magic items and piled it in the central square of the city.  Since it had been collected  constantly for centuries there was a lot of it and it would take years to carry it all out.  The slaves packed up as much loot as they could carry and left using the various portals into the prime material plane their masters had used to get resources and wealth. Because the masters were no longer maintaining the city, it started to become dangerous to travel within its halls.  Limbo being a sort of primordial soup of chaos is constantly changing unless some being controls a space and uses some means to maintain its solidity (Zelazny's Chaos from the Amber books) Because of the concentration and magnitude of the magic that had held the city together in the swirling chaos of limbo, the city is degrading but at a very slow rate.  Certain parts of the city change randomly as you move through them.  Go down a passage and the passage changes as soon as you step out of it.  Other parts have creatures from the prime material plane that have accidentally come across one of the portals the ancients made and were sucked into Limbo.  A few planar travelers  have become aware of the place and occasionally come into it to dip into that big pile of loot.  The effect of the chaos in limbo causes the occasional wanderer to be horribly mutated or for strange chaos creatures to simply be spawned out of the primordial power of Limbo.  (This is a good place to use the random esoteric creature generator).   There are a number of functional portals that lead to many worlds in the prime material plane so some very powerful mortals use it as a way to get to and from the outer planes or on business between worlds of the prime material plane.   Because of the chaos element I can use it make up any kind of crazy shit I want and it is internally consistent.

The characters were informed of the place because they needed to get someplace on an errand for someone else.  They needed to use a portal in the city and had to travel to it using a map they were given that was some what incomplete.  They are a bit cowed by the joint though because they aren't sure they want to be messing around in Limbo.

I'm with you on using At the Mountains of Madness as the inspiration; it looks like it'll be something called 'The Black City' or 'The Lost City of the Hyperboreans'.  I loved 'Beyond the Mountains of Madness', the Chaosium follow up to the Lovecraft story.  I'm picturing a sprawling ruined city (similar in concept to the old adventure module 'Dwellers of the Forbidden City' - that introduced the Yuan-Ti) except placed in the frozen north, with huge dungeons beneath the city.

It'll be a sprawling ruin of basalt buildings and strange, cyclopean architecture.  The ancient Hyperboreans were a prehistoric race of decadent men, the first users of magic. The ruins will have elements of weird science and alien magic. Perhaps the city was built in a time before the world shifted on its axis, rotating the land into the arctic circle.  The dungeons would get warmer the deeper you go, lingering effects of Hyperborean technology.  The dungeons themselves will be the ancient laboratories and halls where the Hyperborean scientist-wizards perfected their arts; there will be no lack of strangeness down there.

Anyway, I need the monsters to be stranger and more alien than a traditional D&D game.  No standard humanoids, for instance.  But at the same time, megadungeons are usually a mix of things:  populations of resident monsters/inhabitants; set piece encounters and fantastic destinations; wandering monsters; bosses and memorable encounters.

I'm thinking repeated encounters with the 'regular inhabitants' will make them seem a bit more mundane (even if they are cannibal humans or atavistic descendants of the Hyperborean's ancient slave races), but those set piece encounters could be truly memorable and horrible.  I think it can work!

The Shaver Mystery provides a slightly different model.  Imagine an abandoned city of an ancient race, filled with marvels the ancients consider inconsequential toys.  Among these toys are biomechanical servants, split into two factions: Teros whose Asimov circuits are still working, and Deros who have become savage and insane.  Deros occasionally raid the surface for new victims to torture and eat, not always sequentially.  They use telepathic rays to seek out victims to drive insane, for fun.  Sometimes they have dealing with other horrible things from outer space.

Let's also assume Deros have booby-trapped the city, hoping to trap the remaining Teros.  Oh, and it's difficult to tell Teros and Deros apart: some Teros have patched themselves again and again, waiting for the masters to return, and some Deros retain attractive humanoid forms despite the corruption of their minds.  (Because pretty = good and ugly = evil is boring.)

Last edited by fmitchell (2010-12-11 04:30:08)