“They say that once, much of Sigil was extremely well-mapped and orderly. The portals never changed, and it was fully cataloged which keys and which gates under which arches or in which cupboards led to certain other planes and cities. A handful of different trade guilds got together and mustered armies to patrol narrow corridors of traffic all throughout Sigil, where beeswax or indigo would pass in wagon trains.
The story is the trade guilds grew so powerful that they began to build barracks and covered tunnels directly from one portal to another. There were spotless manicured lanes that spanned miles, cut off from the rest of the city, and upon them horse drawn caravans raced day and night. And the guilds would either throttle entirely or else charge a monopolist’s fee for passage through their portals.
Then at some point this irked the Lady into action. In a single night she smashed all the newcomers’ renovations, and in living flesh she roamed about the city, flensing alive any who bore the symbols of the trade guilds. The streets ran red with blood, supposedly, and not just in The Hive. She let loose a plague of small biting insects whose venom was harmless to the mortal citizens but instantly deadly to beasts of burden. She made the gate keys more obscure, and she began to periodically shift the locations of important portals, so that one might be lost for a century or more. And it was only the least organized groups, the factions who had not enough coin to alter any part of Sigil to their liking, who were spared. And to this day there is a constant paranoia among the faction heads to never rise too far nor exert too much order, lest it erupt the whole city again into a great holocaust.
Do you know that story?”