Keep of the Oathbreakers (inspired by Of Life, Death, and Delight which in turn was inspired by Adams Family)
Swearing themselves to a forgotten goddess of War and Plague, the Seven Harvesters were the sworn defenders of a once proud empire. The Harvesters rode upon the backs of nightmares, bringing death and disease to all who would dare to take up arms against the people they had been blessed by their Lady to defend.
Their goddess was not an evil deity, but neither was she kind. To her the relationship between god and worshiper was a binding contract, where the sacrifice of blood and joy on the part of mortals was rewarded with that which was in her express power to grant - strength in war and freedom from disease. The Harvesters were her husbands and brides on the mortal plane, never to take up lovers lest they be punished for being unfaithful.
Therein lay the tragedy of the Seven, for though they loved their empire and honored their goddess they had been but boys and girls when they first began the necessary training and transformations that would see them reborn into vessels capable of housing the fell magics of violence and sickness. It was only natural that two of them would come to love each other, though which two committed this betrayal is lost to time.
And then one day the primordials rose up, and the goddess was caught up by a new war in the silver skies of the Astral heavens. It was then the two lovers used the distraction to flee, killing one of their own number in the process. The four loyal Harvesters purused them but the surprise of the betrayal had caught them unawares and they were too wounded to give much chase. It was then that the empire's enemies, made aware of the sudden weakness by their own gods, quickly united to invade the theocracy built on blood sacrfice and violence.
Within their mountain keep, a place far from the ruins of that shattered empire, the lovers remain, undead warrior mages finally together but unable to express their emotions through the nearly fleshless bones that reamin to them. Wounded by their fellows to edge of death, only by turning themselves into liches could they keep their souls from entering the domain of the goddess they had betrayed. They fear true death, and seek out any means they can to unravel their ties to the goddess.
Where once they were great warriors, they are now scholars though they retain their power over war and plague. They use these weapons to keep the lands around themselves in constant strife, ensuring the surrounding forests and grasslands are overrun by petty warlords who are easily manipulated into doing the lovers' bidding. Those few times when peace seems unavoidable plague strikes, but since none are aware of the keep in the mountains none know what the cause of their continued misfortune.'
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There's also a great illithid planar metropoli by RipVanWormer here.
Here's one adapted from one of my organizations based around parallel multiverse sliding (see sig) -
The Mirrored Halls of Infinite Recurrence are a massive, living maze that shows you ways you might have been better and ways the world might be better without you. The Maze is a cruel being, though it is questionable whether it is evil or a harsh teacher. Remember the girl or boy that got away? Well, you actually are happily married...in another possible timeline. Remember the time you wished you were brave? The time that you look back on where you know you should have been kinder, where you didn't think far enough ahead to the consequences? Other versions of you did better when the same trials were presented to them, other versions lived better lives for different reasons. Perhaps they received that kindness you only wish you had been given as a child...
The maze will also show you places that people that are different because you were never born, and they all seem better for it. You see places where maybe someone you care about is happier because they are with someone else, or a student excels because they had a better teacher than you. You see, in essence, the benefit of your absence. Imagine your spouse decided to leave you and then having an amazing life. Imagine your children running away from home and not missing you or deciding that even though they miss you it's better this way...
The trick to defeating the Mirrored Halls is realizing that you can change, that you can understand why you are the way you are and then transform yourself. That the maze is refusing to show you the ways in which your experiences until now can be used to help or at least warn others, that you may not be perfect but there are many that have been touched positively by you. The Mirrored Halls ultimately show illusions, because no one else is you and so no else can judge you so completely...especially not an immovable sentient construct! As one wanderer through the maze puts it:
"If I can understand myself, I can forgive myself. And if I can forgive myself, I can transform myself..."
The Observatory is built on a mountain, separated from civlization. Fungi of various sorts (including bioluminescent ones) grows all over the place, but beyond that there is sparse vegetation and the animals are all sickly if not outright deformed. There is a massive telescope that radiates magic, and extensive well cared for libraries. However, every other structure in the place is dilapidated and crumbling, though the resident astronomers - all healthy if not blessed attractive physiques - don't seem to mind.
Those who stay here for an extended period of time as guests come to find that the astronomers are all gnomish warlocks who have made pacts with the aberrant lords that dwell on the other side of the night sky. They are fundamentally changed inside, as spilling the sickly sweet black molasses that now passes for their blood will show. These lunatics are alienists seeking to open a way between the stars and the world, allowing their masters passageway into the world.
Surpisingly, when confronted they are rather honest about their endeavors and will ask the PCs to join them in their efforts to terraform reality into something presumably more "free" and thus "better". Those who refuse are likely to end up as fodder for the unnatural beings the warlocks' masters have sent to oversee their lesser, once-natural children.
This city appears after a choking sandstorm sweeps over the desert, a fabled acropolis unanchored from Time so that its inhabitants could survive the onslaught of gods, fey, shadows, and primordials. Besieged by the followers of these beings, and unable to find succor in the Planes Above and Below, they fled into Time as the one avenue that remained to them. The city is a wealthy place of summoners who have bound angels, elementals, and other planar beings - even a titan of water serves to provide a close approximation of modern plumping. The residents have designed magical collars to subdue their charges, and drag them around on thin, enchanted leashes made near gossamer links crafted from precious metals.
The city consists of a great many alabaster towers and summoning circles and pentacles. The conjurers of this city, when returning into normal time for a span, always attempt to cage new servants from the planes. The citizens subject these slaves to all manner of competitions and tasks ranging from labor to prostitution and the selfish magic users are always craving novelty in their thralls.
The residents, due to their long exposure to the effects of temporal displacement, live each day with little understanding of their own fates. Every now and then they will become aware of what they have done to themselves and at that point they will extract as much information from the PCs as they can. They wish to return to the world but are terrified that their divine, shadowed, fey, and primordial enemies will exact terrible retribution if they do so.
The City that Awaits Us: This city seems to exist in both the Shadowfell and the Feywild but has no counterpart in the mortal sphere. In Shadowfell the undead and shadar-kai show us that this ruined city is a place with breeding pens and nightmarish cetacean livestock in the city's pitch water canals. In the Feywild, the eldarin city is a place of bright and aromatic water gardens, where the flowers offer much magic to the aspiring alchemist. In both place the residents are confused by the lack of a mortal mirror, and continually tell the PCs of events on the mortal plane that presumably haven't happened yet.
The Beekeeper Hag: In the forest an old woman, presumably an evil hag, keeps bees. Many of the surrounding villages are convinced the woman is somehow connected to demons or devils or some other fell power in the planes, though for some reason this doesn't stop them from buying her honey and putting it on just about everything. The honey is always traded via the intermediary of forest tribesfolk whose ancient pride was broken long ago by slaughter and subsequent introduction to varied drugs. These tribesfolk say the woman is actually the proxy of a gentle earth goddess whose name they have sadly lost the right to speak.
The Weeping Skull: Somehow a skull has grown into the wood of a maple tree, only part of its face juts out of the bark. Sap runs down its cheeks. To taste the sap is to be granted strange visions offered up by Primal Spirits who dance and enjoy other pleasures around tree invisible to the sight of mortals. Those who sleep under the tree have dreams of the skull talking to them, telling them of its dark and storied history when it existed in the head of a living being...and while its been a long time since you heard the tales, you swear you know who this legendary figure actually is...
The City that Sustains Us: In the Winterlands the mines were drying up, the elk and mammoth were dwindling in number with every migration. A way of life that existed for centuries, that had risen on the backs of the proud and the strong in the wasteland left after the Titanomachy, seemed to be coming to an end. Then the new city came, the city of tents and travelers that had somehow walked across the frozen ocean. They have wonders to trade along with necessities, and with their arcana they allow hunters to track game longer in the snow, to venture out further into forest and ice floes in search for game and fish.
They are a boon, but I don't think they are a godsend...because every so often they don't have the shadows of men - too many limbs writhing in the wind...
The City that Holds the Sleepers: This city is a somnucropolis, where everyone is asleep a la Sleeping Beauty. The city is in the middle of a pan-dimensional lake, which means trying to get to it invariably results in crossing paths with creatures from the Feywild and Shadowfell if not higher/deeper realities. The city is on an island that is a giant cinder, though the city itself is a beautiful argent place with delicated filigree overwriting the surface of every single building.
For some reason all the sleepers are children, dressed in the clothes of the city's varied professions.
Our City is a Gift from the Wolves: In the dark forests there is a city that enjoys a steady supply of game and healthy crops. Everyone here worships the wolf packs that seem to inexplicably leave them alone. Everything from the temple altars to clothes to the serving bowls are decorated with lupine sculpture, stained glass, etches, embroidery and paintings.
Is it just a matter of simple respect? Is there some benevolent primal spirit or god? Or is there some dark sacrifice at work here?
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Also love RipVanWormer's fiendish gate cities -> Void's Edge where wereravens compete with fiends and Abattoir in Hell.
The City that Fell from the Sky: This city comes from beyond the circle of the world, and apparently one it danced in the Void among the stars. The city is a collection of spiraling towers that have pierced the earth, creating deep wells where once they extended to great heights. The inverted city invites many explorers into its strange alien confines, not the least of whom are the drow and the illithids that seen their Underdark gutted by the crash of this sidereal metropolis.
Within the city one finds the glowing green metal thrums with a possibly organic heart beat, and the denizens have all placed themselves into some kind of suspended animation pods resembling transulcent violet fruit. Apparently well aware of their city's violent descent, they have left several of their own undead and aberrations to guard them.
The Invisible Ocean: Deep within a bone dry canyon the world phases with another, creating a place where ghostly images of undersea life swim through stone and over dusty bleached bones of aquatic life long dead from drought. Every so often, the worlds align just enough so that these creatures can touch, sting, or bite those trekking through the canyon.
On both worlds there are cultists who are seeking to open the way completely between the two worlds, believing in some prophecy about the tanar'ri Demogorgon and obyrith Dagon that requires the conjunction.
The Ant March: Upon the distant mountains that stretch across the horizon there are bonfires burning, and the wind carries the sweet scent of smoke over miles. The taste of it has even gotten into the rain. For some reason ants of all shapes and sizes and being called to those fires, and this creeping tide is overrunning villages that the ants devour to sustain themselves as they continue on their pilgrimage.
There are reported sightings across the lands of hooded beings that seem like a cross between these insects and elves, but many feel like these are rumors just out to make a bad situation even worse, or explain something whose answer cannot be found anywhere else but on those distant mountains. What is known, because you can see them from a distance, are the larger ants, the ones the size of horses, that seem to be leading these expeditions.
The Horse Cutter: Somewhere in the woods is a sadistic freak preying not on men but on horses. It steals them, and possibly lures them away with the use of enchantments. Days later people find the equines' mutilated forms on the edge of the forest. What are the strange symbols cut into the horseflesh? Why do no flies or other vermin dare to touch the bodies? Why does the plant life around the corpses die off as though each murdered horse bore some blight filled aura?
And perhaps most troubling of all, why does this monster need their eyes and their teeth?
The Well of Karrud: The Well of Karrud is a well filled with water that tastes like rotted meat in the mortal world. In the Shadowfell, the well is at the center of a city of concentric circles. Each circle is a community that becomes more and more monastic as one gets to the center. So in the outer circle you have a metropolis and at the center you have a monastic community that is a nigh-necropolis as in the last circle all that is left to do is make the final preparations before one jumps in the well.
Each circle takes one further toward the life of an ascetic, specificlaly the legendary kind of guru fable in the East for being able to subsist on little more than dew and light. Each circle is also less capricious and evil than the ones before, as if the gloomy effects of the Shadowfell are being countermanded. This leads one to ask what is at the center of the well?
The monks in the inner circle would say the god Karrud awaits, the god who is the darkness of the subconcious. Cleansed of hate, fear, and even despair, the monks who enter the well are meeting with the god who is themselves - the darkest part they buried like all mortals do. Of course, to see these fabled monks in the center requires entrance through the circles, something not easily granted by Karrud's ogre mage militias that prevent fraternizing between circles as well as allow traffic to flow toward the center. Only these oni are given leave to determine who is worthy to enter each successive circle.
The city is incredibly diverse, drawing members of all races fom all walks of life. Apparently the city manages to draw in people not from your world... Note: Loosely based on the god Kud from Korea, who I was told watched over the negative, darker aspects of human nature. A god of evil who isn't evil himself essentially. Liked the idea a lot! =-=-=
The Locust Graveyard: At some point, perhaps to prevent famine or to stop some dark ritual, millions of Abyssal locusts were magically drawn to this chasm to suffocate on the poisons that seep out of the earth. The vapors are both a hallucinogen and capable of draining the body of vitality in a matter of hours. It is unknown who provided the glyphs on the walls of the chasm, magic apparently strong enough to lure thunderheads of demonic insects to this place and keep them here until they finally passed away.
What is left is a chemically preserved pile of insects that, due to their demonic heritage, retain glimmers of life. In fact, after their deaths they should have vanished back to their homeland, but some interaction between the misty poison and the magic of the glyphs prevented that. Their collective ghost haunts this area as a ethereal titan known as The Goetia, a spectral swarm that attacks anything around it as it cannot return to the Abyss until it is destroyed of fulfills its original purpose to destroy some nation or family. To attempt this in the present would mean killing some lineage that perhaps one of the PCs is either a part of or the sworn enemy of.
Note: Sorry, should have given credit where it was due, but was trying to find the correct reference. The Goetia means "The Howling", as of right now I can say I got it from Alan Moore's Promthea as it reference that buzzing home of the demons. Where he got it from I can't say.
The House of Horns and Hides: There is a ruined, lifeless town that carries the smell of a menagerie. Though no animals can be seen, the smell of wet fur and the sounds of many beasts are carried faintly through the fog that prevades this place. While walking through the fog, at some point you will hear the crunch of bones. Looking down to see what you have stepped on, it becomes clear to you that the bones are those of a human or demihuman.
The center of the town is a manor, with quarters for servants, a stable, and many many trophies of animals. These remnants are from animals are mundane and magical, various bones, horns, hides, and other body parts that are preserved in jars and some kind of light pink amber. Whole bodies have seen the touch of the taxidermist, but you do not recognize these specimens.
What happened here? Does it have anything to do with the pilfered religious relics that are hidden in the manor's vault? Where are those relics from, and what primal spirits are they beholden to?
The PCs had better work fast through the notes left in the manor, the bloodspattered journals must hold some clue. The fog is rising, and the sounds and smells of the beasts are getting closer and closer...
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The Mercantile Willow: A giant willow tree grows in an otherwise forsaken woodland. It radiates a sense of safety and the various monstrous creatures that prevade the land cannot come near it. However, once the PCs seek its shelter they will find that the willow itself is drawing more of the creatures to the very edge of its protective boundary.
It wants something from the PCs in exchange for safe passage - the defeat of a rival tree deep in the swamps, a tree with its own ability to command the reptiles of that dismal place. Now the PCs must lead the beasts that hunted them, serving as the willow's champion. But what happens once the war is done? Will the willow honor its bargain?
"In Darkness our world in stupor lies, Yet dotted everywhere, Ironic Points of Light flash out wherever the Just exchange their messages..." -Auden, 'September 1st 1939'
A manor that appears to traveling heroes in the far and dark places of the world, an inn radiating warmth and light in the wastelands of the frozen north and a respite from the insects and jungle's humid sweat in the wildlands near the equator. The Fairy Sisters' House is a boon to those who seem to have been forsaken by both Fate and the gods.
Within one finds a place that is short on visitors, or at best its spacious common room is moderately packed, but the inn is always teeming with orphans of various races and various ages. The Sisters seem, suprisingly, like mortal women who work long and hard to tend to their charges and to offer respite to those who fight to make the world a better place. They are not the flawless ethereal beauties of the Feywild, and yet the very strength of their seeming humanity makes them all the more beautiful and all the more heart breaking.
Yet anyone who approaches them romantically is politely rebuffed, in a way that brooks no argument. No reason is usually given, though sometimes they tell a particularly kind visitor that they are pledged to Another.
Who are the Sisters? Some say they are the nuns of a benevolent god, one who loves the world and so provides a House a gift, an ever moving candleflame of the Light in the benighted world. Others say they are fey daughters who forsook Paradise because one of their sisters knew the love of a mortal, a love that does not end when wrinkles begin to show and frailty overtakes the form. Yet when they departed their archfey parents cursed them, saying the very thing they sought, this so called "higher love", must be denied to them for a mortal who loves them with such purity is cursed to know darkness and despair. Still others say they are all succubi who have risen, and now pledge themselves to some god of light in exchange for redemption.
The Gloom Boxes: The Gloom Boxes are a collective term for the jails, asylums, and most unfortunately orphanages and refugee camps that simultaneously exist in the world and in the emotionally draining glooms of the Shadowfell. Designed to make the charges within their confines more tractable, many of these facilities are now haunted ruins left in disrepair. They might simply apper abandoned during the day, but one quickly realizes the anger when the sun goes down and the undead reclaim the places of their cruel deaths.
Those Gloom Boxes that are still intact are places where the charges seem drained and docile, and while heroes should be quick to free the innocent and the youthful, there is some truth that incredibly dangerous prisoners are controlled by keeping them in these arcane jails. Of course, why some of these dangerous criminals need to be kept alive is another question - for some communities it is done because they cannot bear to their loved ones a death sentence. For others it is because there are family connections, or perhaps some noble or wizard hopes to draw out secrets of buried treasure or lost magic from the killer or thief.
The Windswept Tower of Roses: This Tower seems pristine but abandoned, surrounded by briars bearing rose blossoms. It is always a border season here, Spring on the edge of Summer, or Summer leaning into Fall. The area around the Tower switches between these two climates randomly, but the shift always occurs at night. Winds continually sweep into the area, carrying the scent of the flowers and resulting in a whirling cyclone of rose petals surrounding the Tower.
Both the wind and the animated, regenerative briars will act to keep anyone from getting too close to the Tower and none of the village folk have dared in a long time, though there is always a pack of young fools that end up meeting their deaths here - you can see their bones and rags pinioned on the great thorns of the briars.
When the moon is full and visible in the sky, adventurers have heard the most beautiful voice singing from the Tower, though the exact nature of the voice - a man? a woman? a child? and what they want - rescue? a queen at their side? - is never something those who hear the singing agree on.
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Crossroads House - A house that in truth is an almagation of different buildings across reality.
"...The one place Architects have managed to create, in a sense, is the Crossroads House. Originally thought to be a Multiverse of its own, it was later found the House is made partially from overlapping parallels for which it serves as a nexus while sections of it seem to exist as an independent, albeit finite and small, Multiverse..."