The Spiral Underworld, (PROSE: The Book of the War, Daring Initiation) also called the Spiral Underground (PROSE: A Farewell to Arms) or the underground, (PROSE: Alien Bodies) was a collective term for the criminal organisations of the Spiral Politic.
After the destruction of the renegade Presidency and installation of the world processor engines, Dronid became the center of the time technology black market. (PROSE: The Book of the War) It became the go-to destination for illict trading in anything from dystronic weapons to TARDIS parts. As such, it became home to a wide number of organised crime networks, notably including Faction Paradox and InCorporate. (PROSE: Alien Bodies)
The War in Heaven originated as a complex gang feud between the Spiral Underworld groups on Dronid, which transitioned into a greater interplanetary conflict during the Cataclysm. (PROSE: The Book of the War)