The Glass Dungeon is a huge plug of clear volcanic glass sitting in the corpse of an eroded mountain like a gem set in an old corroded ring.
If you can imagine a lump of igneous rock from the heart of an ancient volcano, then the volcano gradually eroding over time, leaving the much-tougher stone standing almost proud with only a small slope of soil and scree around it.
This would be a lot like the stone which Edinburgh castle rests on.
Then imagine that, instead of hard igneous rock, the stone is volcanic glass. This would be like a mountain or hill of glass sitting on the surface of the earth, its sides and top washed clear, with buttresses of soil and stone running up its sides to about half way, or two thirds of the way up.
The glass isn't completely, perfectly clear, but you can see the colour of the sky through it and light catches and rebounds it inside like a prism. The sunrise turns it gold at dawn, the last red light of sunset stains the whole thing crimson while the sky is nearly dark. The full moon gives it a silver glow. Lightning makes it flash.
Let’s say this is near the north pole, or this is a world with a highly active magnetic field so the glass mountain would reflect the aurora borealis. The light of the aurora moves around inside it.
In the night, even when its overcast, you can see dull red glows moving about inside, reflecting and refracting from the glass walls. This is because the glass is riddled with tunnels and rooms.
The only way into these tunnels is from the top. You have to climb the glass mountain. There are steps carved spiralling round the sides. Once you are up there you can gain entry and walk down the glass steps into the glass tunnels.
It's difficult to be exact about what rooms and corridors are where when they are distant as the glass warps things and a corridor is just an empty transparent space in a transparent block, but you can see all of the immediate corridors and rooms.
You can look down through all the levels of the dungeon and see every solid thing. When there is daylight, aurora light, strong moonlight or lightning then you can see all the way down. When it’s dark, any living thing that needs light to see lights lamps and you can see all these little pools of light moving around in the rooms and corridors.
There is a spring of water running up through cracks in the glass, coming out the top as a fountain and then running back down through channels. This provides sustenance and takes away waste, but it also means that some things that look like walls are actually stable, continual falls of water, you might think you are looking at someone through a wall of glass until they suddenly jump through it.
The sound of the rushing water runs through the whole complex, making it difficult to hear people calling out or moving around.
You can see a huge room full of treasure, you can see all the furniture, all the doors, and you can see all the living things. There's a bunch of Knights in shining armour who are hard to spot because their metal reflects the light so much. A bunch of Orcs carrying flaming torches which stain the ceilings with soot. A bunch of quite-attractive nuns and some tall figures who are almost invisible because they are draped in shimmering crystal veils.
And right at the bottom you can see the Crystal Dragon who's dungeon this is, curled in a glass cavern by a clear, flat pool of mercury which acts as a huge mirror. The mercury re-reflects everything again from below, increasing the lighting effect.
And all of these groups can see each other and can see you. You can see them seeing you and see them seeing each other.
The curious and interesting thing about the idea of a Glass Dungeon is that it destroys or inverts exploration and replaces it with observation and interpretation. The idea here is something like a huge game of Pac-Man.
You can already see pretty much everything (you think) in the dungeon. Once you get used to the distortions it’s hard to get lost. You know where everything *is*, you just don't know what it *means*.
Whereas, in a normal dungeon, you explore and explore and explore just to put together scraps of knowledge and situational awareness and usually, when you encounter something, they are paratactic encounters, happening one after another like a string of pearls, generally separate, and if the dungeon reacts to you as a gestalt, it does so slowly and often ineffectively, in the glass dungeon you get a deep strategic overview of what’s going on, maybe before you even go inside.
It's very hard for anything to sneak up on you, or for you to sneak up on anything else, so your decisions are more like the player of a strategy board game than like a normal dungeoneer. You move to maximise advantage, to force other factions to reveal their nature and intentions and to make sure when an encounter takes place it happens on your own terms.
This is why I kept the number of factions and encounters minimal, the DM has to keep track of *all* of them *at the same time* and each time the PC's do something the rest will respond in their own unique way.
The only way to play this one out would be to have the map right there, and tokens for the moving elements and to update them each exploration term or whenever the PC's made a move.
Because of this as well, the glass dungeon should be a relatively *small* dungeon. It’s good to have multiple interconnecting levels as this adds strategic depth but if you have a shitload of rooms then the DM is going to go nuts.
It also helps if you can fit everything on the same page. THIS map by Dyson Logos might be a good possibility.
(Edit - it was THIS one by Christian Kessler that I was thinking of.)
And it helps if things aren't what they seem, so there are layers of revelation that you can't expose just by looking at something.
So my idea for factions would be like this;
Orcs - These are frightened Doppelgangers who have assumed Orc form as those are the scariest things they can think of.
Knights - These are Orcs who have clad themselves in bright, shining armour which they polish constantly. They have done this as the reflective qualities of the armour combined with the bright, refractive light of the dungeon, means that if they are still, they are very hard to see. Almost invisible.
Veiled Figures - These are Gnolls who have made curtains and cloaks of shimmering crystal and fragments of glass for a similar reason to the Orcs. They can be seen easily only when they are still, when they move, the shifting light of the glittering reflective shrouds makes them virtually invisible.
Nuns - Labradorite Were-Wolves (which Cedric just invented and you should go and look through that link because it’s a great image (EDIT ok Cedric just took that post down for unknown reasons sooo.. just imagine the really cool idea he had(EDIT AGAIN they are back! He is a complicated guy so look while you can)))) and their change is triggered by the Aurora when it shines through the glass.
The treasure room is a hive of mimics.
The Crystal Dragon rests on the remains of a defeated Crystal army, stacked like a mountain in its pool of mercury. If you defeat it and go full-Aspergers on the crystal pile you might be able to re-assemble a crystal golem of your own, but you will need every piece and it might have some crazy old primordial-war programming of its own.
As well as that you can throw in treasures from Chris's excellent post HERE The singing crystal spear, crystal gnome, giant crystal skull, crystal helm and crystal cage are favourites.
The Crystal Dragon is protected by an army of crystal golems, like the terracotta army, but, of course, you can't really see while they are still as they are transparent. When they break they go off like a prismatic ray grenade. Maybe it keeps them under the surface of the river that runs through its lair in a clear, cold stream, they would be almost impossible to detect under the shimmering surface, then they surge upward on command, their shapes highlighted by the water running down their sides.
The Dopple/Orcs are trying to escape the Dungeon or reach the ‘Nuns’ but are avoiding everything else out of fear, whilst acting as if they might be incredibly dangerous.
The Orcs/Knights are trying to reach the DoppelOrcs so they can team up and then rob the Dragon.
The Gnoll/Veils are trying to kill the DoppelOrcs because they think they are the real Orcs and are considering hunting the ‘Nuns’ while avoiding the ‘Knights’, whom they fear.
The Labradorite Were-Wolf/Hot Nuns are trying to reach the 'Knights' to persuade them to help but are acting scared of the 'Orcs'. (In reality, they could probably kill the fuck out of any of these factions but want to preserve the secret of their true nature so they can use it to get close to the Crystal dragon and assassinate it, then steal the pieces of the Crystal army and re-assemble them for some nefarious purpose. They will be exposed when the next aurora shines, but this will also heal them of any damage and give them regeneration while it is active, making them even more dangerous.)
The Crystal Dragon is watching all this with the greatest possible amusement. As well as its army of Crystal Golems it has Glass Golem assassins waiting for anyone who proves to be a danger. These are almost completely invisible in the Dungeon, shaped like spooky cloaked elves with jagged glass assassin knives. They are full of nerve gas so even if one is smashed it kills anything nearby.