The Valeyard

Played by Michael Jayston

"Only by ridding myself of you and your misplaced morality, your constant crusading... Only by releasing myself from the misguided maxims that you nurture can I be free!"

Prosecutor at the Sixth Doctor's trial, the Valeyard attempted to find the Doctor guilty of interference and genocide, a verdict that would result in the death penalty. He presented damning testimony from the Doctor's affairs on Ravalox, blamed him for Peri's apparent death on Thoros Beta and the genocide of the Vervoid race. As the trial culminated, the Master revealed that the Valeyard was in fact an incarnation of the Doctor himself - an amalgamation of all the Doctor's potential darkness from a point in the his future. After a pitched battle with the Doctor in the dreamscape of the Gallifreyan Matrix, the Valeyard died when the weapon he intended to turn on the Time Lords overloaded. However, as the Doctor departed with all charges against him dropped, it was clear that the Valeyard had survived...

The Great Intelligence later mentioned the Valeyard as one of the names the Eleventh Doctor would have "before the end."