Wilderness Beyond Time

The Wilderness Beyond Time was the realm to which the Guardian of Time fled from the Time War in the Warrior's universe. Mortals would normally be driven mad by what they saw. A cave existed there that served as a gate for the Old Ones to be summoned forth.

When the Warrior and Davros were brought to the Wilderness, Davros saw himself as a young man before his accident and swam in a black hole, although the Warrior still saw his scarred visage. Conversely, Davros saw the Warrior as the tall, curly haired man with a scarf who was there at the creation of the Daleks. (AUDIO: The Key To Key To Time)

Behind the scenes
In the main universe of N-Space, this realm's equivalent would be the Six-Fold-Realm.