Note that the below describes a single instance of a Skeletal Assembly Line room. It functions on its own, but if one of these rooms exists, then there are likely more of them. Hidden behind stone walls and false book shelves, producing the tools of war and sending them to who-knows-where for who-knows-what purpose. If this room is used, the GM is encouraged to hide several similar rooms. And don’t forget to add material gatherers to the random encounter table!
The secret door was more difficult to find than most; just a sliding section of wall in the middle of a corridor. The players never would have found it if they hadn’t seen a skeleton run by with an armful of old chains, then be gone from sight too quickly to have used any of the visible exits. Even with that to go on, it took the characters an hour to finally find the loose stone which, when turned, unlatched the hidden door and allowed it to swing open freely, revealing a short corridor leading to a room filled with the red glow of a fire.
Within the room was like nothing the players had ever seen. The soundproofing on that door must have been remarkably, because the characters were suddenly assaulted by a cacophony of sound once they stepped through it. Flames roared, hammers clanged, and the omnipresent clacking of bones against steel and stone. The room was filled with skeletons, dozens upon dozens of them, each repeating some mundane task over and over again. And not a one of them paid the intruders any mind.
Right in front of the players as they entered the room was the pile of refuse; dead adventurer’s armor, a thousand goblin spear heads, countless belt buckles and chains and other detritus. All of it steel. Skeletons swarmed over the pile, disassembling each piece, discarding anything that wasn’t steel. Leather, cotton, twine, even gold and gems were tossed into a wheelbarrow held by another skeleton. When it was full, the skeleton would wheel it away down another corridor, out another secret door, to dispose of it. Another skeleton with another wheelbarrow was already there to take the place of the first.
The steel that was left over was piled into another cart on a small rail. Whenever it was full, it was rolled up a ramp and dumped into a boiling vat of liquid metal. When the steel was ready, the skeletons at the vat would tip it forward, spilling the steel into a mold where it was shaped into the component parts of blades. A half dozen skeletal smiths cooled these parts in a communal pool of water, and hammered each piece into the proper shape before other skeletons take them to sharpen on a whetstone, before finally dropping them onto the conveyor belt.
Still more skeletons standing on either side of the belt deftly assemble the swords component pieces into usable weapons. Leather strips for the sword handle is periodically carried in by a blood-covered skeleton who probably comes from a similar room elsewhere in the dungeon. Given the denizens the players have encountered in the dungeon so far, they can only imagine the leather comes from goblins, orcs, or human adventurers like themselves.
The belt is turned by a skeleton with crank in hand, who moves it at a perfectly efficient speed to allow all of the work to be finished before it reaches the end of the belt, where the completed swords are dropped into a mysterious chute. The swords can be heard sliding against the stone for a long while, descending to some unknown depth for some unknown purpose. Who, the players wonder, could possibly need so many swords?
At least they have one clue to that riddle. The final step before the swords are dropped into the chute is for a strange symbol to be engraved on each blade. The players don’t recognize it, but perhaps someone else will? At least it’s something to look out for as they delve deeper into the dungeon.
The skeletons will continue to ignore the players indefinitely. Even if the players attack one of the skeletons, it will do whatever it can to continue working at its task for as long as possible. A disruption in the production chain will be noticed, however. The skeletal assembly line is a well oiled machine. And the moment any given skeleton no longer has a task to perform, they will immediately attack any living thing in the room, whether it’s a rat, or an adventurer.