6. The Return of The Valeyard
First introduced in 1986 in the 6th Doctor's Trial of a Timelord, the Valeyard is introduced as the prosecutor for the Time Lords intended to railroad Colin Baker's Doctor in an elaborate Galifreyan trial for "conduct unbecoming a Time Lord." Later the Valeyard (which means learned court prosecutor in Galifreyan) is revealed to be a future incarnation of the Doctor, existing between his 12th and final regenerations. Twisted and evil, he tried to use the events of Trial of a Timelord to steal the 6th Doctor's regenerations and extend his life. The Valeyard's name has been dropped several times during the 11th Doctor's reign most notably by the Dreamlord (a character with some remarkable similarities to the Valeyard) in Amy's Choice and by the Great Intelligence in The Name of The Doctor. Could this have been foreshadowing the return of this classic Who villain, perhaps in the form of John Hurt?