Pearl (From Out of the Rain)
Pearl, was a companion and accomplice to the dark ringmaster, the Ghostmaker. She enjoyed bathing in, smelling, and tasting water. She travelled with the Night Travellers in the Joshua Joy Travelling Show from the late 19th century onward. The Ghostmaker described her as the "closest thing you will see to a living mermaid" and described her as capable of living on the ocean's floor.
After the end of the Night Travellers all that remained of them were memories and films. It was from these films that Pearl and the Ghostmaker escaped. They set about taking away the last breaths of people, yet leaving them alive as an "audience". They collected the breath in a silver bottle. Pearl took great delight in drinking people's tears. She and the Ghostmaker robbed a film of the Night Travellers from Jonathon Penn's flat. She filled the bath there and submerged in it. Afterwards, the pair travelled to the old cinema and played the tape releasing the remaining Night Travellers. Jack Harkness filmed them all and exposed the tape, destroying them as they were just a film. Jack claimed that Pearl and the Night Travellers could return if there were more films of them out there. (TW: From out of the Rain)
