The Dreaming is the home of dreams and nightmares alike. All stories written and unwritten, all songs sung and unsung. It is to the Dreaming that mortal minds travel when asleep. The ideologues and even Primarchs find their first nascent sentience in the Dreaming, pulled together by flicking sparks of intent married to the heat of the Source.
The Dreaming is closely allied with the elves of the Tuatha de Danaan, and through them, the guardians of Otherworld, their cousins of the Seelie Court. It is at the walls of The Dreaming that the gates to Nullspace can be found, and the Unseelie Court sends an endless flow of warriors to man the battlements and repel invades or sappers.