This article was first broadcast in Episode Two Hundred and Five on 30th March 2022.
Sigil, known alternately as the City of Doors, the Great Cage, and the Center of the Multiverse, is one of the major landmarks of D&D.
It got its start in, and some would argue defined, the Planescape setting. The idea of a cosmology for the D&D multiverse had been around since 1987, when the first Manual of the Planes was published. However, the rest of the planes only really existed as places where other beings came from when they either invaded or were summoned to the Prime material plane. Or they were locations where the souls of mortals went when they died.
By the time 2nd edition rolled around, people were clamoring for more information about the planes and wanted to actually adventure in them. TSR tasked David “Zeb” Cook with developing the setting, and Planescape was published in 1994.
Planescape was designed to be a location people could adventure in at any level. The challenge was that all the other planes were ones of extremes: the elemental planes were almost entirely made up of the element they represented, requiring things like fire immunity or flight to survive in. The less pleasant planes had destructive demons, devils, or similar things running around in them, and Celestia had a bunch of angels and gods that would either ignore or banish annoyances. So Mr. Cook knew that there had to be a relatively safe and hospitable “home base” that was not only possible for 1st level characters to get to, but also wouldn’t immediately annihilate them.
Sigil is that place. It is located in the Outlands which is the so-called true neutral location in the outer planes that connects to all of the other major ones. Sigil is above the Spire, a tall, thin mountain in the center of the Outlands. It is not on the top of the mountain except semantically; Sigil floats above Spire’s peak.
The city itself is always described as “Shaped like the inside of a Torus,” which seems annoyingly pedantic even to me. A torus is basically a donut shape; this one just has a flat interior edge. Sigil is built along the entire edge of the inside. So yes, if you are standing at any point in the city and look up, you will see across the ring to the rest of the city.
The ring’s diameter has been variously measured as being 5 miles 8 kilometers, or 6.4 miles or 10 kilometers. Those of you who remember how to calculate a circumference can try to calculate the area, but it’s also pointless because the city’s size isn’t fixed. It can be altered at the whim of the city’s master, the Lady of Pain.
The city itself is extremely cramped, because of its nature. Sigil features an uncountable number of portals that connect literally everywhere. There are portals to the Prime Material Plane, any of the 9 hells, anywhere you like in the abyss, even other settings’ worlds. However, like the city itself, all the portals in the city are under the control of the lady in charge. If you don’t have her permission or one of the keys that links to a specific portal, you can’t use them.
There are a lot of people who can and do use those portals however, and that has led to Sigil becoming the equivalent of the biggest old world trading port ever. People have come from anywhere imaginable and either traded things they brought from their home plane, or they decided to set up shop and start selling those same things. As a result, Sigil has the reputation of being a place where you can find almost anything imaginable for sale. That includes a number of magic items, many of which Sigil has produced itself. A number of artificers and wizards set up shop producing magic items, since the exotic and otherwise rare materials they would need are much easier to find.
In addition to all the people selling stuff, a lot of others set up buildings and houses to accommodate the travelers coming through. Sigil has a permanent population around 50,000, but over 250,000 travelers coming through and temporarily staying at any one time. So much effort goes into making the transient population feel welcome that some accommodations are said to feel exactly like a piece of a particular plane or city has been moved to Sigil. The side effect of that, however, is that there’s constantly construction and rearrangement of architecture and remapping the city. If you’ve got a group of 200 humans from Baldur’s Gate moving through, people will literally build up housing for them to stay in. Then once they move out, it all gets remodeled to accommodate the crop of demons that wandered through on leave from the blood war.
Now with all of the mixing cultures and individuals from different and sometimes opposing planes, there is friction. However, the Lady of Pain likes to keep a lid on any large scale conflicts. In fact the city used to have a bunch of different factions in it that controlled various aspects of life in the city, but when inter-faction conflict erupted, the Lady’s response was to eliminate or dissolve all of the factions. She also permanently keeps any gods, archdemons, archdevils, or similar god-like beings from entering the city. However she doesn’t concern herself with petty issues like small-time crime or minor skirmishes.
Despite that, Sigil is not a constant free-for-all of fighting, stealing, and general mayhem. Many people benefit from having a central location that’s basically neutral in all respects and sells a whole lot of merchandise. The citizens maintain that by sort of self-policing in an effort to make sure everyone is, if not welcome, at least tolerated. A common example is that people will say you can go into a bar and see an angel and a devil both drinking there and possibly even chatting. It’s likely they’ll be hurling thinly veiled insults and barbs at each other the whole time, but they won’t be trying to annihilate each other in combat.
That said, the locals have no sympathy for rubes that wander into the city totally ignorant and hope to just bully their way through. Sigil has good and bad neighborhoods like most major cities, and given how much the landscape changes and how crowded it is, it’s easy to get lost. An entire industry in Sigil just centers around guiding and transporting people around, and if visitors don’t avail themselves of that, the locals figure they get what’s coming to them.
For larger problems, the Lady has a few different options. First of all, her complete control of the portals means that if anyone tries to march an army in, they’ll only get maybe a few squads or a regiment in before the portal closes behind them and can’t be reopened. Then the lady can forbid whoever they are from ever leaving by locking them out of all the portals, the origin of Sigil’s nickname as “the Cage”. And if things get really bad, she can always show up herself.
No one is actually sure what the Lady of Pain is. She hovers as her primary form of movement and is always dressed in flowing robes that obscure most of her body. Her head and face seem to be a mask that show a humanoid, vaguely female face with many blades thrusting out around it like a particularly dangerous flower. Anyone that directly challenges her never lasts long. Her mere gaze has been known to cause bloody wounds to simply erupt on a person’s body, and on multiple occasions she has simply willed someone into a demiplanar maze she is apparently able to create on a whim.
There are vague rumors that she has some sort of relationship with and connection to the Raven Queen, but given that no one really knows what she’s about either, that’s not terribly helpful in figuring her out.
For a long time Sigil was the place to be if you wanted to run an adventure that involved spending a lot of time somewhere besides the material plane. Sigil provides a stable place to use as a staging area that is, if not safe, at least not actively hostile to player characters. It also gives lower level characters access to things they might not otherwise find right away. Most DMs would not hand a bunch of boots that gave a 30ft fly speed to an entire adventuring party at level 1. But if the campaign needs them in the Elemental Plane of Air by the time they hit level 2, then a Sigil shopkeeper may have an errand they can do to get a discount on some footwear.
It also gave an excuse for why characters that low in level are plane-hopping. The portals in Sigil are not static, and the lore set up that they can form around any physical structure that resembles a doorway. So it’s entirely possible to accidentally end up in Sigil and then be stuck there.
Unfortunately there’s very little information about Sigil in 5th edition. It has been mentioned, but only in a throwaway fashion, such as the DM’s Guide mentioning that an option for adventures is to have the characters plane-hop using Sigil. Since it has always served as the cornerstone of Planescape as a setting, it would make sense for it to show up as part of that if it ever debuts. Any other information would have to come from legacy sources.