Xoriat, the Realm of Madness is a plane in the cosmology of the Dungeons & Dragons setting of Eberron, commonly nicknamed "The Orrery". Beyond description or comprehension, Xoriat is aptly called the Realm of Madness. Not only do its alien geometry and unspeakable inhabitants seem like the product of a madman’s nightmare, but any who visit Xoriat risk finding their minds shattered by the experience. Xoriat has been likened to a sack of transluscent parchment, an apparent infinite connection of layers and dimensions. Its inhabitants exist on multiple layers simultaneously. Massive, drifting entities, too large to notice visitors to the plane: free floating rivers of milk-white liquid: rains of blue globes falling from unknown heights, only to burst and release horse-sized ticks when they strike another object – such are the madness-inducing features of Xoriat. Gelatinous worms wriggle from layer to layer, wending through tentacled vegetation encrusted with orange moss, all suspended above an amoebic sea. Landscapes like that exist alongside places like a house made entirely out of hate, an expanse of nothingness that represents life, or a farm tended by mind flayers whose crops are emotions.
The Daelkyr are the most powerful inhabitants of the plane that have an interest in the material plane. Their motives are fundementally alien, but they've been compared to artists and scientists – except their canvasses are mortal flesh and their experiments involve twisting civilizations. It's even possible that dragonmarks are the result of Daelkyr experimentation. Each person who looks at a Daelkyr sees something different - a human may see a perfectly formed human wearing living armor, a goblin would see a mighty bugbear warrior in the skins of his enemies, while a dwarf might see a crude imitation of a dwarf wearing a cloak of eyes. They can also choose to appear a certain way, and the way they look is often determined by their current obsession. Their thought processes are so alien that trying to read their minds results in madness, and if a Daelkyr focuses its full attention on you, it breaks your mind (represented in 3.5 by their ability to cast confusion at will). They made a project of twisting worlds - at one point they invaded the gith's world and corrupted them into the mind flayers.
Like Dal Quor, Xoriat’s last time of being coterminous with Eberron was a disasterous period of warfare. Over 9,000 years ago, Xoriat became coterminous, and the Daelkyr sent their minions into Khorvaire against the empire of Dhakaan. Legions of mind flayers, beholders, and other aberrations descended upon the goblinoid and orc lands. The Daelkyr then twisted the native races of Khorvaire into servants - they made dolgrims from goblins, dolgaunts from hobgoblins, turned orcs to madness, and crafted countless other aberrations. Before the orc druids known as the Gatekeepers managed to alter Xoriat's orbit, the forces of the Daelkyr had mortally wounded the Goblinoid Empire of Dhakaan, waiting for the seeds of madness they planted to kill it. To this day, Khorvaire is plagued by the various Cults of the Dragon Below spawned by the Daelkyr (alongside the ones dedicated to Overlords or Khyber itself). The Gatekeepers' magic was less cataclysmic than the giants’ attempt to close the connection to Dal Quor, however; Xoriat moved quickly away from its coterminous position, but it is sure to return one day. The combined forces of the Gatekeepers and the Empire of Dhakaan worked to seal away any Daelkyr that remained into the depths of Khyber. The Gatekeepers maintain the seals to this day, but the Daelkyr are in Khyber waiting for the seals to break, all the while putting their unknowable plans into motion and sending their servants to do their will. The Daelkyr don't appear to be in any rush to break the seals though - possible explanations range from them not caring because they know the seals will break in a few thousand years, them being content in Khyber because they can move around and enact their plans anyway, them not noticing they're sealed, or even the horrible possibility that they wanted to be sealed.
Besides the Daelkyr, there are a number of other entities and aberrations that live in Xoriat. Those massive entities mentioned in the first paragraph? Yeah, each one of those things is on par with an OVERLORD. They're mostly content to sit around in Xoriat though, warping the landscape around them. Communities of outsiders and mortal aberrations make their homes on the islands of stability they form, while others hang out in the insane places in-between. Almost all aberrations in the setting come from Xoriat, or were created by the entities there from inhabitants of other planes.
All that bring said, it's not COMPLETELY bad. The inhabitants there call it the "Realm of Revelation" instead of the realm of madness. Some of those islands of stability are an okay place to live, if you can adapt to how weird and alien they are. It's also a realm of creativity; many talented people were inspired by the place. You can learn some pretty sick magic there, and it's one of the sources of psionics in the setting. But overall, it's a pretty horrible place for any sane person and contact with Xoriat is almost always a bad thing for the person involved.
In case it's not obvious, Xoriat is the Eberron version of the Far Realm - with one key difference. The Far Realm's defining trait is that it is outside conventional reality, but Xoriat is a key part of conventional reality - it's as much the realm of revelation and inspiration as it is madness and insanity. That means alien incomprehensible things man is not meant to know are a key part of reality in Eberron. Grimdark.
- No Gravity
- Highly Morphic
- Mildly Evil-Aligned
- Wild Magic
- Distorted Time: Time flows differently on Xoriat than Eberron. One minute in Xoriat is equal to one hour on the Material plane. So, adventurers from Eberron that visit Xoriat for one hour will return to find 60 hours have passed.
- Coterminous: When Xoriat is coterminous, madness literally bursts forth upon the world. For reasons unknown, the Shadow Marches are somehow ‘close’ to Xoriat, and the natives of Xoriat were able to enter there during the last coterminous phase. Throughout the Shadow Marches, magic went wild, and the Daelkyr warped native creatures into monstrous aberrations. The intervention of the Gatekeepers altered Xoriat's orbit and the plane has not been coterminous since. Dimensional seals keep the plane away but various forces seek to break their power so Xoriat can draw near again.
- Remote: Xoriat’s remoteness has no known effect on the Material plane.
- Aberrant inhabitants, that include: Daelkyr, Mind Flayers, Pseudonatural Creatures, Rukarazyll, Wyste, Kaorti, Odopi, Shrieking Terror, Voidmind Creatures.