The Time Shades were legendary beings on Gallifrey, with reports of their existence going back as far as the Dark Times and the days of Rassilon. They were intimately connected with various aspects of time.
There was a "pantheon" of Time Shades, including the Shade of Eternity, the Shade of War, the Shade of Dreams, the Shade of Protection, and the Shade of Portent. Their forms seemed to escape all light and shadow.
The Shade of Portent was able to see the future, and knew that Narvin, a Time Lord of relatively low rank, would become pivotal. It abducted 5 students from the Academy, freezing them in time, in order to draw him in. (AUDIO: Damned if You Do [+]Loading...["Damned if You Do (audio story)"])