Mapper

The Mappers were a class of cartographers created by the Great Houses early on in the history of the Homeworld. Auteur was said to have originally been a Mapper, although Intrepid believed this was a tall tale he had invented to give himself more gravitas.

History
After the Anchoring of the Thread, the Great Houses had succeeded in shaping the broad arc of History, but, in the process, had made the Spiral Politic into a fixed "vast expanse" that they needed to explore if they were to call themselves Lords of it. Thus, after the first few experiments which resulted in monsters and mutations, the first successful births from the Looms were devoted to the creation of Mappers.

The Mappers, armed with the Observer Effect, mapped out the meridians of Time. They built instruments such as astrolabes and "dared into the frightening mists of History", "sailing" through History's beginning and its end. Once they had returned to their offices, the Mappers "doped up on any hallucinogen" and plugged themselves into the Homeworld’s computers, creating the first maps of the Spiral Politic from their memories.

However, once their work was done, the Mappers were said to have all gone insane. Like ordinary Renegades, they took on new names, but instead of meaningful titles, they took what Intrepid to be "really stupid names, all trying to work with a timekeeping theme", such as Astrolabe or Pendulum. In the end, the Mappers, "like most of Homeworld history", were forgotten about and drifted into legend.

A rumour existed during the War in Heaven that Godfather Auteur of Faction Paradox, infamous for his abuse of the Observer Effect, was a surviving Mapper. The story was embraced and retold by Auteur himself, who even claimed he had been the one to map the first meridian. Cousin Intrepid, however, believed it was a fabrication that Auteur had made up with his "drinking buddies" to make himself sound important, only to start believing it himself due to his insanity. (PROSE: Going Once, Going Twice)

Parallel universes
In Barusa's universe, the early Time Lord explorers, some of whom went mad or never returned from their journeys, were known as the Time Explorers. The Doctor's own father, Ulysses, was such an explorer. (PROSE: The Chronicles of Doctor Who?)

Behind the scenes

 * Although Going Once, Going Twice is deliberately coy about whether Auteur really is the same individual as Astrolabus, it is, at any rate, the unavoidable implication of the text that Astrolabus (a semi-legendary Time Lord who appeared in several DWM comic stories) was a Mapper.