Though it wasn't mentioned in Ultima IV, this is the place the Stranger reached at the end of that game after getting to the bottom of the Abyss, as this is where the Codex rested at the time of the Quest of the Avatar. This place was ret-conned into the Shrine of Singularity in Ultima VI. The Codex of Ultimate Wisdom was taken by the Great Council from the Shrine of Singularity after the events of Ultima IV, and moved into the Shrine of the Codex. As with the rest of the Realm of the Gargoyles, the shrine was probably destroyed after the events of Ultima VI.