I’m stealing this from Patrick Stuart, as with all of “my” good ideas.
This is a plane. It has settlements embedded inside of it. Its organizational principle is simple to describe, but (and this needs to be stressed) it’s infinite, so any finite account of it is necessarily incomplete and contradictory. I’d been calling it the Astral Temple, but as I thought about my needs, the word Temple as a generic organizing principle for this place has become less useful. And Astral, as an adjective, I don’t find useful to describe what I’ve wound up with there. Previous editions of D&D named their planes and then added detail, which is how we wound up with the Clockwork Nirvana of Mechanus — it had been called Nirvana, and then we decided we wanted gears. Here, I’m willing to ditch a name that’s not serving me any more.
Imagine Relativity, that famous Escher print. The City has the same color scheme; chalk-white marble, black granite, grey lead, black iron, white ash. “Down” depends on where you stand; while each point in space has such a down and it is independent of terrain, it’s obviously not uniform, and there are areas of hyper- and null- gravity, twisty corridors which war between bases, ceilings that become walls that become floors. Light is eerily without source: similar to a blacklight, white objects emit their own glow, and a large proportion of the stone is white. The white lights throb gently, breathing minute-long exhalations of glow. Explorers use white sheets to see by. Where the sky can be seen, it is a grey static cloud mass, gently a-glow, in every direction.
The stone and iron and lead are growing, too. An archway that leads down a staircase studded with alcoves will find those alcoves becoming archways to new galleries spotting framed mirrors and new fountains. The pace is sedate but continuous, with the floor of a room seeming to drop a few inches every year. The seeds of architecture yet to come can be dug out by miners, twisted doorways and bonsai statuary foetal in the rock.
Everything appears hand-made and decorated, full of meaning. Every lintel is inscribed with a poem, every flagstone a mortuary marker, the cobblestones mixed with potshards bearing scratched receipts for grain sales. Windows of a thousand styles offer views between rooms equally ornate: perhaps an arabesque grate on one side of the corridor permits a view into a gothic stained glass arch on the other side, for all the world like the alleyway between a church and a mosque. Perhaps a chimney offers views through grates, grilles, pits and firedogs into smoking dens, caves, wainscotting, screens and plaster. Books and scrolls and tablets and carvings and paintings can rub shoulders, for all the world like an antique shop.
Everything is eerily quiet, the vast stillness of the place drinking sound. There are still-working fountains sometimes (the strange gravity of the place sometimes settles into a sort of perpetual motion), and their bubbling trickle feeds mosses and vines. A patient traveler can hear the vines expand, growing towards white marble on grey-brown tendrils.
The Gates of the City
The City is a leaking sieve of manufactured spaces, due to its odd relationship with gravity and topology. A city square might have a plot of grass with a tell-tale force shimmer. One who stepped upon that grass might find themselves vertiginously between planes for a moment, in the City but also on the Talenta Highlands of Eberron, smelling the saurial dung not five feet away. The City generally has a negative pressure, pulling material from the plane to which they are attached into itself. However, this current can sometimes be opposed (as though it were a cataract of rushing force), and varies in strength, sometimes pushing outwards.
Often, gates respond well to certain objects or behaviors; there are tales of gates which respond to the touch of an elf, the sound of a drinking song, the presence of a laurel wreath. Myths persist of doors which open to the touch of a faithful man, in the time of truest need, or when a millenarian cult’s faithful fulfill their prophecies. However, in most cases, it’s simply time and conditions: sunlight, storms, the angle of the stars.
Wherever a gate appears in the temple (whether a coterminous plot of land or a freestanding active gate), the area around it takes on some nature of the other sides’ character. Of course some of this is due to infiltration from the gate: dandelion seeds or horseflies might cross over during an inhalation, or a lunatic poet. But more frequently it is a natural process of the city itself: the architecture matches the style on the other side, the statues the people, the writings the language, through no obvious process.
While any border or archway can form an attachment to the city, manufactured doorways, mirrors and paintings seem particularly to do so.
The Contrafactuals of the City
There’s another insidious pattern to the art of the city: it never happened. The statues are of kings celebrating victories they never tasted, queens where there had been kings, tyrants who had been kind, princeling descendents of lines ended in bloody revolution. Not everything is always a lie, or at least not obviously so (a painting portraying a general on a white horse they did not ride seems more like acceptable artistic license than a lie), but it remains the fact that the City gets things wrong and extrapolates.
A stairway with the busts of the rulers of Bretonia (each set in an alcove) likely gets several of them wrong: this one with a scar they did not have, this other one listed dead as a child, and each one after that a foreign monarch from the Black Forest instead. And perhaps a doorway off of the staircase, leading into a library whose books are in that barbaric sylvan tongue, outlining how victory was achieved in the conquest the reader knows did not end that way. And perhaps a doorway to a staircase from there, leading into a corridor whose windows describe the life of a baker at the edges of the Black Woods, littered with sacks of worthless ash. And from there, doorways at either side: one of portraits of a minor noble miller’s family, and the other to a statue of a sailor holding a rat pocked with plague.
Another example of this is where two rooms abut each other, a newly developed third one might show a confused view of history, spawning imagined interactions and consequences which never could have happened. This sprawl spreads in both directions, flourishing in infinite variations as it climbs.
Artifacts removed from the City age poorly. The iron rusts too fast, the stone is soft and crumbles, paper goods rot within days. Caveat emptor.
“Up” seems to lead mostly towards imagined pasts and consequences, melded together from the old growth of imagined events. The further “up” one climbs, the murkier it can sometimes become; the risk of an intersection with some other branch of the City greatly increases, and the odds of the results becoming a muddled mess increase dramatically.
“Down” seems to lead towards gates to places and times which have that nature of the real which the black-and-white City lacks. It doesn’t point “into” the gates, so much as into clearings which contin the gates: gates tend to orient in a clearing, and paths tend to lead downwards towards them. Not all gates define such a down, and which gates do seems to be quite random, but the fact remains that heading down will often eventually find gates and, possibly, civilization.
The Contrafactual Gates
The final wrinkle in the City is that not only does it open onto a thousand thousand worlds, not only does it contain the works of a thousand thousand possibilities: it opens onto possible worlds. That is to say, at the end of a historian’s search through the rooms of the City into a place they believe to be a seeded gateway from which the other rooms of the City were derived, they determine the passcode for the doorway and pass through. The space they pass into might be a whole and vibrant world, connected through other portals. But it might also be a smaller shadowy slice of a world, distant in time and space, closed in on itself. A traveler might have found a path through the City which connects to their own world twice in two different locations, but perhaps instead the second connects to a shadow of their world, reflecting historical changes like those in the City.
These Shadow Worlds can be a dangerous trap, since they may not be stable. Sages conjecture perhaps that is the way of the City at all times, absorbing whatsoever it connects to. This has (eventually) dire consequences for all of the worlds which touch The City.
Monsters in the Wilds
Where the city grows strange, far into the maze of rooms, there are often impossible creatures lurking. Sometimes they’re creatures called in through a gate or set by some ancient mage to guard a gate. Sometimes they’re hypothetical creatures, who might have been called up by some ancient mage to guard a gate, had that mage existed. Sometimes they’re forced out from a settlement formed around a gate, grown strange and large in the distance. And sometimes, they come from Outside.
Many factions cluster in the city around its entrances and exits. These places represent safety and security for those who hold them: an extra way to leave, access to fresh water, air, and food, and trade opportunities. Some factions hold sway across large swaths of the City, expanding their borders and establishing their law. Others exist within others’ settlements as a philosophical bent or a simple social club.
Modrons. The mechanical modrons are a race of self-replicating constructs which seems to originate in the City. They are made of its grey wood, soft stone, and hard iron frames. Their disturbingly fleshily-rendered eyes and lips are set in geometric bodies. They single-mindedly destroy all art with which they come in contact, which can frequently set them at odds with other factions in the City. However, they are otherwise quite willing to peacefully coexist with others, so long as they are willing to regularly cede art and meaning to the Modrons to be destroyed. Knowing that there is non-ephemeral art out there lying — and to a modron, all art lies — seems to offend the modron to its very nature.
In contrast to their attitude towards the written word and statuary, once they’ve defaced any meaning from the art, they defend the structure, stability, and architecture of the city valiantly. In many locations, modrons prune back weeds, repair damage from water, or create new aquaducts to better inhabit the city. Many believe the modrons to be the original builders of the City, but sages retort that the City grows, whether modrons work at it or not.
There are reports of modrons manufactured of non-native materials like brass and cherrywood; those are reportedly cheerier and much friendlier towards non-modrons. Their hierarchy is unclear, but simpler figures respect more complex figures; the more complex figures in turn seem more capable than the simpler ones.
Gith. Gith are the most frequent humanoid inhabitants of the City. They tell tale of generations of slavery on the wormworlds, under the thumb of illithids; their founding hero Gith fought them free and the race named themselves after her. After finding escape in The City they destroyed the gateway through which they fled, and formed a schism between The Faithful of Gith (Githzerai), who held this act of desecration was unforgivable, and the Children of Gith (Githyanki), who place no special religious faith in the place they found themselves. The two types of gith are violently opposed to one another, uniting only when faced by incursions of their former masters such as illithid or slaadi.
Githzerai. The monastic settlements of the githzerai often occur far from any gates, or near dangerous or undesirable gates. They subsist on gardens which they grow in the City using water from fountains which they clarify alchemically and plants grown in the strange light of white walls. They spend their time in toil, exploration, contemplation and prayer. Their strange religion seeks the source of all things; to understand the order of events which occurred in the many worlds (Chronos) and the order of events which occurred in the City (Kairos). They are opposed to the modrons particularly, who destroy the Sacred City. They are also frequently encountered in the “gardens” of their monasteries which lie in Limbo, as they find the contrast allows them better able to concentrate — and some say, to shape the growth of the City in turn.
Githyanki. The piratical Githyanki, on the other hand, devote themselves to war-like pursuits. They raid the City for materials, locate and analyze gates, and then raid the other side of the gate for what they can seize. They establish dominions, build fortresses, and tunnel through walls. Much of what is known about mining in the City comes through them. Their largest settlement remains Tu’narath, the place through which the Gith first made their redoubt when fleeing the illithid, and which now opens onto that dead world. They use the architecture and art of the City to locate new gates through which to make war or to sell their ill-gotten booty.
Tieflings & Hell. As Hell is the largest and most sophisticated consortium of worlds, it would be odd if they did not have a presence in the city. And, indeed, representatives of the Iron City began an incursion into the Endless City in a now-forgotten age. Dis claims this act to be a reconquest; that the City originated as did Hell with the first free-willed being’s home, and that all of the City is theirs by right. However, they also aggressively seal gates leading from their worlds into the City (under the guise of operational security), and react poorly towards gifts of materials from the City.
Minotaur. Nobody’s quite sure how it happened, but there are a whole bunch of bull-headed guys wandering around The City. They come from a variety of worlds, they generally have little magical ability themselves, and they are uniformly male (though breed true when the opportunity presents itself). Somehow, however, they all seem to know each other, and find themselves drawn to the City. Many tinker-style traveling merchants are minotaurs, traveling in the City from gate-town to gate-town, selling their wares.
Archmages. For some reason, archmages from a dozen worlds really enjoy the cosmopolitan nature of the City. Maintaining a presence of some sort here is practically on the archmage final exam. Liches, mummies, and other undead creatures made out of former mortals now clinging to power also make up this class.
Priests & pilgrims. A place which duplicates the works of man is like catnip to a godbotherer. Many, many religions hold the City to be a sacred place, worthy of at least a pilgrimage. As otherworlds go, its conditions are sufficiently similar to Material worlds that visitors need only ensure the gate they use is safe. Frequently an abandoned gate will be the haunt of an angel, naga, sphinx, or lamassu, left behind to guard the space until pilgrims use it once again. The pilgrims who are encountered in the City are visitors and tourists, and generally overpay for a trinket which will not age well back in the World.
The Lady of Pain. A floating porcelain-masked figure, or perhaps race of figures, made of silk and steel. The City shapes itself as she wills it, her shadow flays by touch, and she frequently teaches a lesson by banishment via teleportation into a random labyrinthine segment of the City. She punishes particularly those whose actions too-radically affect the city: it seems that the expansionist modron and the reconstructivist githyanki do not try her patience, but the Temple of Aoskar for whatever reason did, and that lesson isn’t lost on the powerful: groups which attract her attention may be destroyed in a heartbeat, with no warning.
Our planescape-like factions are going to be, again, stolen straight from Patrick’s article.
Academicians: “The City teaches us who we are”. The academicians are the most powerful and popular faction, because they uphold the status quo of the City, such as it is. Their actual interests are strongly divided; between Contextualists (who seek to understand the events on which the city bases itself, using near-historical events to understand true ones), Counter-counters (who reject all counterfactual evidence as irrevocably tainted), the Stylists (who ignore truth in favor of beauty) and the Originalists (who seek the seeds of events in the city for their own sake). In all cases, their relationship with The City is, well, academic: they publish papers and vie for respect within their organization. The Academy’s store of knowledge produuces maps, gate-keys, supplies of trade goods, and of course security for expeditions deep into the City. The Academy is based out of the gate-town of the same name, which shares a triple-gate to the City of Brass, the Iron City, and the so-called Bright City of Hestavar
Alienists: “The City is bounded by Outside”. A splinter group of counter-counters who engage with the city as a dangerous foe, the alienists are adventurers who seek personal fame, generally by trying to explore the edges of the City. They’re the source of rumors about Outside, strange creatures tied to no known world. The fame and fortune they seek is driven by artifacts they can bring back from the edge, showing un-City-like influences, new worlds, or similarly shocking news. The alienists are based in the City of Brass, where the cosmopolitan Efreeti are intrigued by their ideas.
Anarchist League: “The City was ours, and we’ll kill you and take your stuff!”. A popular faction of bandits and thieves, the Sodkillers oppose the Harmonium on the basis of a war back on Ortho — the Sodkillers claim to be the true descendents, pushed back from their gate towns by the following invaders of the Harmonium. They’re a sort of rebel-alliance which opposes the Harmonium in particular, but any sort of central rule in general. They have no central base, but can frequently be found sheltered in gith settlements, finding favor in their loose structure.
Athar: “It’s just another place, you know?”. The faithless are based out of the Iron City, and hold that the City has some interesting properties, but it just isn’t that improtant; they oppose the Academy because the academy’s entire goal is based on ignoring the Worlds in favor of the City. Their sponsorship by the trade consortia of various unsavory planar powers (the Iron City particularly) has led to them being considered somewhat unsavory.
Believers of the Source: “The City was started at the first moment of creation”. The believers hold that the City is in fact related to the demiurge, though are divided over what to do with this fact. They work out of the gate-town of The Foot of the Throne, a famous pilgrimage site with a gate to Celestia. Some believe the City to be itself holy, and thus only to be visited by the shriven (Godsmen); others, that none can be suitably shriven but that the City will forgive (the Bleak Cabal), and yet a third faction that the previous two are both correct, and so everyone who has visited the City and then chosen to leave (without intending to return) is guilty of a great sin (Anti-revolutionists). Central to all three groups is the search for the Throne, the center of the City.
Cynics: “The City is chaos”. The cynics believe that there is order in chaos, but a surface understanding leaves one unable to see it, and that the City in particular has a many-layered approach to truth which can be difficult to perceive. They are often difficult to predict, erratic, and intuitive. They control Arsanith, a githzerai-controlled gate-town, but can be found in many other gate-towns as well, because their teachings are tempting to the powerless.
Doomguard: “All things fail; the City before us”. The Doomguard, from the Citadel Exhalus is the Nether, seek to cause gates to the city to swallow the area into which they open. They believe if they can cascade enough property into the City, its danger to the other worlds will be at an end. There is some evidence they may be correct.
Fated: “The rich resources of the City belong to who can hold them”. The Heartless are a primarily human faction driven by amoral observation of fact. From their gate-towns of Columbia, Fountainhead, and now-flooded Rapture, their agents see what they can get. Other than those gate towns, the city-state of the Fated isn’t expansionistic (they’re nervous about what they actually can hold!), and tends to favor proselytization beyond their own borders.
Harmonium: “The City is an obvious extension of Ancient Harmonia”. A former nationalistic polity whose gate was lost to modron expansionism, their secondary gate-town of New Harmonia (opening onto a stretch of idyllic world called Ortho) has made peace with the modron border. They’re a fundamentalist, authoritarian bunch.
Sensates: “The City is great! Where else can you get Dothraki takeout at 3 AM?”. The hedonistic (and materialistic) sensates seek to take advantage of the juxtaposition of cultures which the city creates or, if further along that particular path, exploit the actual edges of the city, mining them for new experiences and treasure. Their materialistic ways make them an enemy of the Academy and gives them a complex relationship with the gith. They are based out of the Festhall, a gate-town to Azzagrat.