House of Mystery
The House of Mystery is a unique demesne disguised as a large home, old as humanity itself. It is something of a fixed point on the edge of The Dreaming and acts as one of the beacons that direct lost and wayward travelers towards more solid ground of intention. It is a tiny echo of the mighty Demiurge, with its own limited intelligence and power. The dimension was created as a cap on the hole in reality created by Morgan le Fay and her abuse of the Cosmic Cube. It was sealed by Merlyn and the Vishanti to guard against encroachments from the Dark Dimension.
The House of Mystery assembled itself into a home of sorts after Cain was banished there with his brother Abel. For millennia the two men dwelt there, often contacted by Dream or his minions as humanity whipped itself along the path of evolution. Dream and the other Endless banished Cain and Abel to the House for a timeless epoch, hoping that time would heal all wounds. It largely has not worked.