Because there hasn't been much adventuring going on lately (probably something to do with me wiping out the party, I don't know), I'm posting once more about Silvergate. Recently I described the random (and somewhat unexpected) creation of a large lair of Orcs on the 4th level in this post here. About 640 of them, all together, with a fighting strength of around 160, and a couple of Trolls.
That sort of thing isn't necessarily easy to just slot into a corner of a level. 640 Orcs take up a lot of room, so I am in effect designing a lair the size of a small human town around the idea of an Orc-tribe holding a section of the Dwarf-city.
I need to think about a bunch of things:
non-food/fuel supplies (eg wood for tools, weapons etc)
clothing, rope, leather straps etc
social activities (religious rites, community gatherings)
This I think relates in some way to this post about dungeon ecology. How do monsters relate to each other, and what are they actually 'doing' all the time? How do they live? What do they eat? Where is their water coming supply coming from?
More specifically, are these Orcs producing their own food from their territory? Are they essentially 'farming' a section of the dungeon (eating rats and fungus, for example)? Do they hunt for food in the caverns? Are the patrols they send out 'guards' or 'hunters'?
Presumably, their massive quantities of Orc-slurry become the food for something else, which then becomes the food for something else, which is then eaten by the Orcs, and thus the cycle of life continues. But presumably there are some inputs into the system from outside - unless these Orcs are completely self-sufficient. So the idea of sending out regular patrols of Orcs to both sweep the corridors and hunt for food, or strangers who might trade/be robbed of wood or other valuable surface-items seems reasonable.
These Orcs would perhaps see wood as too useful to burn - unless, of course, it's so valuable as fuel to that they don't make mere clubs and spears out of it. Either way I'd expect that they'd be making things out of bone, keratin, chitin etc. Likewise, though they can make leather from rat or lizard skin (for example) perhaps the Orcs would also be using Giant Spider silk for ropes or straps and maybe they've even learned to weave it into fabric.
Without a source of a lot of fuel, iron-working is going to be very difficult so metal weapons are going to be in short supply, unless someone outside is supplying them in exchange for something else. Perhaps along with the bone and chitin, the Orcs are goingto be working stone rather than metal. I think the trick is going to be to pick some things in which the Orcs are self-sufficient and some others that they have to acquire from outside their caves.
There will definitely be a source of water, of that I am absolutely certain. There are several potentials here. The city when it was in its heyday was heavily-populated and the Dwarves were water-engineers. Some aspects of this water-management system survive so maybe the Orcs inhabit an area where the water comes from the Dwarves' plumbing. There are cisterns and conduits - perhaps some of these still work, or perhaps the breakdown of this system just means that some rooms are partly-flooded and these areas become 'watering holes' - either guarded by one faction, or used as a 'neutral space' by different factions.
Food doesn't seem to be too difficult. There are plenty of things that Orcs could eat, that don't necessarily have to appear on the Wandering Monster list or in lairs. Animals, plants and fungi only really need stats if they're a threat to the PCs. Something that can't harm the PCs, but is no use to them either (like a giant woodlouse that is poisonous for humans and Dwarves but Orcs find palatable, that can't bite through human skin) doesn't need a stat because it's more like a part of the room description than a 'monster' as such.
Working with these kind of notions should allow me to make the Orc-lair a recognisable part of the megadungeon, without necessarily having to tweak the results of my random rolling too much, which I'm loth to do, as I'm trying to run the creation process as 'straight' as I can get away with.