Celestin was a Time Lord who was sent to Skaro by the Celestial Intervention Agency. He was found delirious with the empty casing of the Dalek Emperor by the Second Doctor.
Raven took Celestin (AUDIO: The Final Beginning [+]Loading...["The Final Beginning (audio story)"]) and kept him prisoner. He said that he did not know who he was, but eventually laughed and said that he was the Emperor of the Daleks. (AUDIO: Wrath of the Ice Warriors [+]Loading...["Wrath of the Ice Warriors (audio story)"])