Mictlan

Mictlan was the extra-dimensional home of the Time Lord faction known as the Celestis, created as a hiding place from the War. (PROSE: Alien Bodies et al)

Mictlan existed in a state of enormous flux. This flux was so corrosive to the rest of the Spiral Politic that it had to be kept on the outer skin of the universe. (PROSE: The Book of the War) As a result, its occupants were immune to time winds or changes imposed on Gallifrey's past. (PROSE: The Taking of Planet 5)

Mictlan was created by the use of block-transfer engines and computational matrices which also linked all the Lord Celestials who made up the Last Parliament. (PROSE: The Taking of Planet 5)

Appearance & geography
The appearance of Mictlan varied with the perceptions of its inhabitants. (PROSE: Alien Bodies) When Entarodora visited Mictlan, the realm appeared as a grey and black landscape with a glowing sky. (PROSE: The Brakespeare Voyage)

The Bone Museum of Mictlan served as a library for agents of the Celestis. It held information on the Eighth Doctor. In addition, there was the Plain of Bones located in this realm. (PROSE: The Taking of Planet 5) The Celestis took those close to death to Mictlan. (PROSE: Autumn Mist)

History
Mictlan was created by the use of block-transfer engines and computational matrices which also linked all the Lord Celestials who made up the Last Parliament. (PROSE: The Taking of Planet 5)

The Eighth Doctor once travelled into Mictlan to confront the Celestis. (PROSE: Alien Bodies)

Entarodora projected her consciousness into Mictlan from The San Grael in order to make a deal with Lord Dervishage involving The Brakespeare. Backup records of this meeting were later given to the Great Houses for use as evidence in Great Houses vs. Scarratt. (PROSE: The Brakespeare Voyage)

Mictlan was destroyed due to the actions of Investigator One, the hermit, and the Fendahl Predator. (PROSE: The Taking of Planet 5)

Behind the scenes

 * was the name of the Aztec underworld.