Arhiod, the world of dreams

This is where all the possibilities of Faerun connect. A world which any can enter but few can enter at will, and where thoughts make reality. Arhiod, the Unseen World or the World of Dreams, exists between the possibilities that existed for each choice made, making it touch the whole pattern of chance. Dreamers who have control over Arhiod are known as Shifters. The World of Dreams covers and swirls around Shadowfell like a thin layer of skin.

Years of Fabrication: History of Arhiod
Since training artifacts for the World of Dreams existed, it is likely that they were used or studied in some way in past centuries or millenniums. It is supposed that this dream realm exists forever, accompanying the cosmos since the day of creation. The Harpers had a shifter called Corianin Nadeal who died centuries ago. Elan Witherleaf, a bard and solitary monk, is the only other known shifter in recent history (more than a hundred years ago). Calishite Fadewalkers, Rashemi Hathran Witches and a number of Halruaan mages also made use of Arhiod frequently, and the gift of shifting seemed to be very common among them in past generations. However, only a selected few through history were really able to grasp Arhiod's nature so as to fully manipulate the dreamstuff.

Shifting is a talent, lost since the ancient days, which is paired with viewing (the ability to read and interpret the past or future events) which also is channeled through Arhiod. Shifting appears to be connected to the Calishites' exercise of Fading (viewing people's dreams with no effect to or from them). They also train their Fades to remember every dream they have when they sleep, which allows them to train their minds on importance and slip out of the ones that are just ordinary dreams.

The Edge of Life: A description of the World of Dreams
Anyone can enter the World of Dreams and those who brush up against it in their sleep, are almost never aware of what they are doing. Many people wake up with pains and bruises that they can not explain, caused by taking small injuries in Arhiod. Shifters can enter the world at will, as well as those who hold certain artifacts. Some of these items do not even require spellcasting to activate them, thus Arhiod can also be accessed by those who do not possess arcane knowledge.

Another way to enter the Dream is to create a gateway to it. Lore scripts however, have warned against this several times, stating that anyone who does so loses a piece of their humanity.

The Dream is malleable; one can project thoughts to make up creatures and buildings. Larger things that are made in this fashion are more difficult to maintain and control than smaller ones. The key to mastering the World of Dreams, as lore goes, is to always remember it is a dream; if one accepts the dream as reality he ends up trapped with a non-reality.

Behind the Mirror: The waking world and the nature of the veil
The real world on the dreaming aspect is named Narhiod. The World of Dreams is a mirror of the waking world, except that it is a nonpermanent one. Objects such as geographical formation, forests, and mountains exist. Buildings exist as long as they have been around the real world long enough to create an impression on Arhiod. An item such a bowl of food may flicker in and out before the viewer's eyes. Wild animals are also part of Arhiod however domesticated animals are not. Some people believe this to be due to their relationship with humans; their connection to nature has been severed.

There is a place between Arhiod and Narhiod, which has no recorded name, while some call it the Void. There one floats and can find the dreams of others, to speak to them in their dreams or to enter them directly. Entering the dream of another is very dangerous, as the dreamer becomes part of the other person's dream and it is often controlled (even unconsciously) by them. It is possible for a dreamer to get pulled into someone's dream against their will if the dreamer has exceptional feelings of hate or love towards them.

Fiendish creatures known as Night Hags use this place as a means to trap people.