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Derilobia was the home planet of Bliss. It had a university, and one of its major cities was City Dome 1.

Carvil manipulated events on Derilobia to create the illusion that the planet had been attacked by the Daleks so that he could turn the entire planet into a weapons manufacturing facility, with his goal being to create vast missiles that would be able to destroy all of the Daleks' ships. Carvil was officially commanded by the Fifth Tamasan, but she maintained a degree of distance from her underlings' efforts to officially allow them to do their jobs as they saw fit.

The Eighth Doctor discovered Carvil's plan when he took Bliss to Derilobia. As it was her home planet before Carvil's actions changed history in a manner, it suggested Bliss was now never born. After learning what Carvil had done, the Doctor rejected Carvil's protests that it was necessary to go this far to destroy the Daleks.

When a Dalek agent was able to make contact with the Daleks, the Time Lords were forced to evacuate with Carvil being left behind as his TARDIS was sacrificed to provide power to all other TARDISes attempting to escape the Daleks' trap. (AUDIO: The Lords of Terror)

Prior to the Daleks invading the Gulf of Ithon, Derilobia had been erased from the timelines. (AUDIO: Dreadshade) Rasmus later promised that he would help Bliss find a new home once the Last Great Time War ended. (AUDIO: Restoration of the Daleks)