Obverse

The Obverse was a mysterious region of the universe in which Time and Space were not only not one, but never had been and never would be. Iris Wildthyme came from there. (PROSE: The Blue Angel, Wildthyme Beyond!)

Mathara believed that the Obverse was "a temporal boil on the flesh of the cosmos" created after the timelines were twisted by the Third Doctor getting infected with the Faction Paradox biodata virus during the War in Heaven. (PROSE: The Ancestor Cell) One implied that the Enclave into the Obverse was a construction of the Celestis' making. (PROSE: The Taking of Planet 5)

Geography
The Obverse was connected to N-Space by the Enclave, a pocket galaxy. (PROSE: The Blue Angel) Another entrance to the Obverse was located through a Ringpull on Hyspero. The Clockworks and its capitol of Saga City were in the Obverse. (PROSE: Wildthyme Beyond!)

History
In conjunction with the War in Heaven, a massive war broke out in the Enclave. While originally limited to the races of the Enclave, Daedelus sent time corridors from Valcea into the outside universe to draw in further conflict; the Daleks and the Galactic Federation were some of the first powers to respond. (PROSE: The Blue Angel) The Meercocks implied the conflict connected to the Obverse. (PROSE: Verdigris)

The Valceans lived in the Enclave, (PROSE: The Blue Angel) but the Meercocks implied they originated from the Obverse itself. (PROSE: Verdigris)

Iris Wildthyme once encountered a version of the Eighth Doctor in the Obverse. (PROSE: The Blue Angel)