As retold in Gallifreyan mythology, the Shade of Eternity was one of a pantheon of Time Shades, records of whom dated back to the Dark Times and the days of Rassilon. Given their name, they represented eternity.
Narvin once met the Shade of Portent in the catacombs beneath the Capitol, confirming their collective existence, as recorded in ancient texts. (AUDIO: Damned If You Do [+]Loading...["Damned If You Do (audio story)"])