Unlike the Great Wheel Cosmology of standard D&D settings, the cosmos Iorth exists in has a unique cosmological structure. The majority of the cosmological existence consists of an infinite expanse known as the Astral Plane, amidst which the planes exist. Almost all planes float, drift, or orbit in the Astral Plane, except for the 3 major elements that are set upon the Cosmic Axis: Heaven, the “bubble” that holds Prime Material Planes and their bound echoes (Shadow, Shimmer, Ethereal), and Hell. The majority of objects in the Astral Plane are demiplanes/quasiplanes/paraelemental planes/shards and the like formed by debris from the orbiting planes occasionally colliding with each other or with some part of the fixed Cosmic Axis; in some instances, such debris collides into each other, and either meld together, cast off more intermingled debris of their own, or obliterate each other.

The Prime Material Planes and their Echoes

The Prime Material Plane of Iorth exists in a bubble of ether, alongside its overlapping/adjacent “echo” planes: the Shadow, the Shimmer, and the Ethereal. But, in addition to this, there are also multiple copies of Iorth (with their own echo planes) spread throughout the “bubble”; these are alternate realities of this multiverse (much akin to the variant Earths of Marvel’s multiverse or DC’s multiverse).

The Shadow, by contrast, is a realm of cruelty, pain, loss, anger, and despair. While the Fey Court rules over the Shimmer, it is the Fell Court that dominates the Shadow. The prominent folk of the Shadow are the dark elves, who dwell in their domain of Moldor. Though host to several domains of dread, it is most known for the horrid realm of Borzalom (a.k.a., the setting called Darkloft).

The Etherial Plane is a realm between realms that links the various realities together. Though generally void of indigenous inhabitants, there is a few sparse, secretive settlements present in its mists (such as the Radiant Citadel).

The goddess Ki dwells/exists in this realm, able to access all of these multiversal planes as she wishes.

At the “upmost/northmost/top” of the Cosmic Axis resides Heaven. The further “upward” one goes into Heaven, the stronger the positive/good influence of the Positive Energy one feels, until at last one encounters the god An on his heavenly throne.

Heaven is a pleasant, peaceful, welcoming realm, consisting of luxurious vistas and lush fruitful landscapes. The skies are clear and blue, with a warming sun and cooling breeze. The landscape gently slopes upward, leading to a colossal silvery mountain with a shining city at its summit: the Paradise of Arcadia. A wide crystal clear stream flows down from the mountain and gently meanders across the landscape. After crossing the rainbow bridge that leads to Heaven, blissful pilgrims lazily ascend the smooth marble path and stairway that leads up to the city, and seek admittance through the shimmering silvery gates of the city.

The massive wheel-like city is well-organized and pleasant, and all are able to make their way easily throughout its streets. At the city’s center is a massive garden and a magnificent white marble tower at its center. This is the Tower of Light, and at its highest point rests the throne room of the god An. Any and all may enter, and any and all may seek an audience with the deity. None within Heaven suffer for want, and none desire to cause discord or displeasure. While the realm does have its rules, every rule is fair and sensible, and unable to be exploited for greed or cruelty. All who are in Heaven have little if any desire ever to leave it.

A countless and diverse array of beings reside in Heaven, but among them all are the titans and the angels. The titans are the noble and good heroes of old deified, who battled the demons in the earliest ages of existence. Many serve as administrators and advisers in Heaven. The angels are the servitors of An and the titans, and dutifully complete the various tasks necessary for a city to smoothly operate. The most common and numerous of the angels are the devas, who frequently interact with the souls and mortals  who somehow venture to Heaven. The planetars are the next higher order of angels, serve as the officials and guards of Heaven, and are the angels first encountered guarding the gates to Arcadia. The highest order of angels are the solars, who oversee the whole of Heaven and serve as the commanders in charge of all beings in Heaven, and who answer only to An or Os directly.

In Gaming Terms (D&D, Pathfinder, OSE)

Iorth’s Heaven is a combination of the Positive Energy Plane along with all of the Upper Planes, though it has absorbed plenty of debris from collisions with all four of the Elemental Planes, it tends to have more air and water elements in the mix. In addition, it has a bit more debris from collisions with the Orderly Pattern than it does from the Chaotic Maelstrom. Though any non-Evil being can reside in Heaven, the plane itself is on average akin to Bytopia/The Twin Paradises in D&D cosmology (a NG[LG] plane). It is the home of almost all non-Evil Celestial creatures and demigods.

At the “downmost/southmost/bottom” of the Cosmic Axis resides Hell. The further “downward” one goes into Hell, the stronger the negative/evil influence of the Negative Energy one feels, until at last one encounters the god Ur on his hellish throne.

In order to understand the dynamics of Hell, it works best to realize that the entire plane is a vast prison. The countless demons and other sundry fiends and beings are the prisoners, and the devils are the guards. Odd as it may sound, the god Ur is both this prison’s most dangerous and feared inmate as well as the prison’s warden. The most powerful of all devils, known as the Archduke of Hell, is seen as the warden, but is actually the vice warden, working in service and answering directly to the god of darkness and chaos. Each major group of prisoners, such as demons, demodevils, slaads, hags, the succubi and incubi, efreet, and others, are roughly equivalent to various prison gangs.

No one in Hell wishes to be there, not even the god Ur. The realm is a place of constant pain, anger, despair, fear, hate, and madness. The god Ur was banished to Hell by the overgod Os, and is incapable of leaving. As angry and bitter as Ur is, the god jealously entraps his servants and other condemned entities in Hell alongside him, ensuring that they suffer as much as he does. Some entities may achieve brief bouts of “parole,” being summoned or escaping briefly to other planes of existence, but ultimately they always return back to the terror of Hell.

The majority of Hell can be described as a massive wasteland with sunless smoke-polluted skies fed by the countless wildfires and volcanoes that dot the plane. Meandering throughout the landscape is a broad, wide river of lava that leads to a massive lake of lava. At the center of this colossal lake is a lone island of razor-sharp obsidian from which is cut out an infernal city: the city of Pandemonium. Countless structures clutter the labyrinthine streets, but in the center of the massive city lies an immense, deep well that leads down to the lower layers of Hell, and ultimately all the way down to the throne of the dreaded Demogorgon, the god Ur.

The wasteland is notable for its unforgiving and inhospitable terrain: surviving off the land in Hell is not possible. Creatures that require sustenance that reside or are trapped in Hell ultimately feed off one another to survive. Breathing is labored and difficult, eliciting frequent coughing fits. Without enough protective magics to withstand the environment, a living creature from the Prime Material Plane ultimately dies from starvation, exhaustion, dehydration, or exposure alone while lost in the wastelands.

Red-hot iron-lined barges can be seen floating down the lava river, with the souls of the damned packed in as a massive towering fiend prods the barge along, ultimately heading to Pandemonium. Once there, the souls are cast out into the streets, to wander and stumble and fall further into the torments of Pandemonium. A few wicked souls either quickly or eventually prove their worth to the devils, and are rendered into devils themselves, but most try to not succumb to the schemes of the various infernal gangs and work to join a gang themselves and ascend the ranks.

The major groups of the damned are as follows:

• Devils are the appointed guards of Hell, ensuring that no one escapes the plane, even though they themselves want to do nothing more than achieve their freedom. Agents of the devils include the scheming rakshasas and the cunning efreeti, as well as some infernal beasts such as the vicious hellhounds and hellwasps.
• Demons are the prisoners of Hell, striving to escape their prison and inflict pain, suffering, and ultimately entropy on all of existence. Agents of the demons include devourers, howlers, and vargouilles.
• Demodevils (also known as demodands and daemons or yugoloths) are the oldest inhabitants of Hell. They are prisoners, but have gained some measure of trust from the devils and demons alike, making them equivalent to “trusty” prisoners. However, the demodevils are ultimately spies and servants of Ur, working to ensure that no one’s machinations to escape or gain power are successful unless Ur allows it. Agents of the demodevils include the seductive succubi and incubi, barghests, night hags, and nightmares.
• Aberrations from the Horror also reside in Hell, with notable ones such as the slaad infesting a section of Pandemonium. The aberrations all work for various allegiances, but all ultimately fall sway under the will of Ur.

In Gaming Terms (D&D, Pathfinder, OSE)

Iorth’s Hell is a combination of the Negative Energy Plane along with all of the Lower Planes, though it has absorbed plenty of debris from collisions with all four of the Elemental Planes, it tends to have more fire and earth elements in the mix. In addition, it has a bit more debris from collisions with the Chaotic Maelstrom than it does from the Orderly Pattern.Though any Evil being and some non-Good beings are damned in Hell, the plane itself is on average akin to Carceri/Tartarus in D&D cosmology (a NE[CE] plane). it is the home of almost all Evil Fiendish creatures and demigods.

The Elemental Planes of Air, Earth, Fire, and Water are planes of pure element that orbits the “bubble” than contains the Prime Material Planes and their echoes. Though constantly moving, they do tend to be in a certain region of the Astral Plane more often than not: the Planes of Air and Water tend to be in the upper hemirealm, whereas the Planes of Fire and Earth tend to be in the lower hemirealm.

In Gaming Terms (D&D, Pathfinder, OSE)

These realms are typically Unaligned (or true Neutral for some residents).

Demiplanes

The Astral Plane is littered with countless tiny realities referred to as demiplanes. There are too many to recount here, but there are a few demiplanes of note that bear mentioning.

Orderly Pattern

The Orderly Pattern is an orbiting demiplane plane that has an elaborate yet set and predictable spherical orbit path around the “bubble” throughout the Astral Plane, with what amounts to “gravity assists” from the pull of Heaven and Hell. It seems that the Orderly Pattern tends to slightly be more in the upper hemirealm than in the lower hemirealm. A notable region of the Orderly Pattern is The Gears, a massive construct that spawns construct servants to eternally work on and in service of the reality.

In Gaming Terms (D&D, Pathfinder, OSE)

The Orderly Pattern is a strong absolute realm of order (LN). Warforged, autognomes, modrons, and other sentient constructs often originate from The Gears.

Chaotic Maelstrom

The Chaotic Maelstrom is an orbiting demiplane that has a wild and unpredictable spherical orbit path around the “bubble” throughout the Astral Plane, with what amounts to “gravity assists” from the pull of Heaven and Hell. It seems that the Chaotic Maelstrom tends to slightly be more in the lower hemirealm than in the upper hemirealm.

In Gaming Terms (D&D, Pathfinder, OSE)

The Chaotic Maelstrom is a strong absolute realm of chaos (CN). Most sentient amphibious creatures like fire and ice salamanders, slaads, grung, grippli, and bullywugs often originate from this demiplane.

This horrid demiplane of absolute madness that serves as home to several aberrations and the great old ones, ancient enemies of the overdeity Os, such as the terrible being known as Yus. This everchanging morass of a reality is home to countless perverse beings. Nothing good comes ever from this region. Rumors speak of the Horror being merely the reverse side of the coin-like demiplane that is home to the cosmopolis known as Aushaus.

In Gaming Terms (D&D, Pathfinder, OSE)

This exodemiplane is home to aberrations such as aboleths, beholders, mind flayers, slaadi, and many others. It is also said that the dread Tarask is originally from the Horror.

This strange demiplane orbits the distant reaches of the Astral Plane, and serves as a lone outpost amid the vast void. The denizens of this realm comprise of the descendants of long-stranded planar travelers and the unique native folk of the demiplane. It holds a bizarre mix of the advanced and the primitive, and it is in a constant struggle to repel invasions from the Horror. It is also home to the legendary demiplane-within-a-demiplane-market known as the Bazaar of the Bizarre, where, rumors say, one can find anything, for the right bargain. Individuals from Aushaus are rumored to be able to travel to other worlds and realities, whether through passing through an interdimensional portal or sailing across the Astral Plane within a techno-magical purpose-built vessel known as an æћerskiff; these adventuring travelers are known as Scapejammers. This cosmopolis resides on the obverse of a coin-like demiplane which, rumors say, hosts the dread demiplane known as the Horror on the reverse.

In Gaming Terms (D&D, Pathfinder, OSE)

The setting of Scapejammer is akin to a mix of classic D&D settings such as Spacejammer, Planescape, and the Radiant Citadel. Options not available in the main setting of Iorth, or which are exclusive to other campaign settings, may be encountered here.

Greater Cosmology

The world of Iorth is not by any means the only realm of its kind. Across the countless dimensions, other variants of the world manifest themselves, and are remarkably different from the original.

A realm of high adventure, the world of Flaith (pron.: Flyth) faces a great struggle between the forces of Good and Evil. The hands of the gods guide mortals discreetly, hoping that the great struggle to rid the world of its impeding doom may yet be achieved by mortal heroes.

The world of Flaith, home of the Wildrealms setting, is akin to such settings as Middle-Earth, Mithgar, Prydain, Krynn, Theros, Wildemount, and earlier edition versions of Faerun.

The world of Gwyrthiol (pron.: Gweer-thee-all) is an advanced and idyllic realm where technology and magic developed side by side, and their advances have elevated the entire world. Flying ships, firearms, mass transit, towering metropolises, and other wonders are common, and many benefit from their invention. However, the power of nations and kings are rivalled by the various Guilds and Orders, and intrigue is abound.

The world of Gwyrthiol, home of the Grandspire setting, is akin to such D&D settings as Eberron, Ravnica, or Strixhaven, or other settings such as Bas-Lag or Ptolus.

The varied and enchanting lands of Wrhymn (pron.: Rim) are a place of high adventure and lost knowledge. It is a world where the bold may make their own fortune through their own hands, and gain fame and wealth by taking risks.

The world of Wrhymn, home of the Hawkmoor setting, is akin to such settings as Hyboria, Nehwon, and other such pulp settings of sword and sorcery alongside foundational settings such as Blackmoor and Greyhawk.

The world of Yarld (pron.: Yarld) is one that appears very familiar to Earthlings, but with magic and mystery abound. Explorers and raiders from the cold northern lands of the Kalmark interact with the folk of the Angevin Islands, while the feuding states of the High Empire fight for dominance.

The world of Yarld, home of the Epic Age setting, is akin to such Earth-like fantasy settings such as D&D’s Mystara, the Old World of Warhammer Fantasy, the Earth-like analogs of Abeir-Toril in earlier editions, or the imported cultures as found in Yrth from GURPS.

The world of Zordon (pron.: Zor-don) is a dreary, grim, ruinous land where the survivors of a great cataclysm must fight to survive amidst the untamed horrors that ravage the land. Lone outposts of civilization dot the landscape, and only brave and foolhardy adventurers risk travel through the ruthless and unforgiving wild. Even still, civilization is no true haven, for the schemes of the ambitious and powerful lead them to plot, pillage, and conquer as they will.

The world of Zordon, home of the Grimvale setting, is akin to such D&D settings as the Nentir Vale, as well as some thematic similarities to settings such as Westeros, Gor, Melnibone, and the like.

The fantastic world of Trendiblenda (pron.: Tren-dee-blen-dah) may appear to those not from there as a quilted patchwork of aspects and elements of many of the aforementioned worlds, yet all present despite what may appear to be jarring inconsistencies. The world is in the midst of a massive war between the forces of the fiery Orn Horde and the frosty Til Legion, while the withdrawn and impartial Gry Sodality watch from afar. However, all of them are unaware of the looming hidden threat of the Klyr that seeks to bring about total oblivion. The world has a diverse mix of cultures, from post-apocalyptic societies rising from the ashes, idyllic wonderlands infused with fey magic, horror-steeped dystopias isolated from the rest of the world, to fantastic magitechpunk megalopolises, all of which are under the sway of the ever-present and ever-watchful gods. Dragon riding musketeers known as dragoons, magical automatons riding dinosaurs, castles in the air that are home to magical schools, interdimensional pirates, and countless over possibilities can be encountered here.

The world of Trendiblenda, home of the Skycastle setting, is effectively a massive blend of all D&D and other such game settings, though it tends to highly focus on highlighting current popular trends in fantasy and popular culture.