War Doctor

An unknown incarnation of the Doctor was encountered by the Eleventh Doctor and Clara Oswald when they entered the Doctor's own timestream. It is hinted that this incarnation of the Time Lord was responsible for a transgression that dishonored his name.

The Eleventh Doctor, upon coming into contact with this incarnation, spurned the very memory of him. He went so far as to suggest this incarnation did not even hold the moniker of "the Doctor" due to his actions in life. He explained to Clara that his real name was not the point; he chose the name "the Doctor" and explained that the name a person chose was like a promise, and this unknown incarnation was "the one who broke the promise. He is my secret." This unknown incarnation responded by defending those actions, stating he had "no choice" and that he did what he did "in the name of peace and sanity". The Eleventh Doctor acknowledged this as true, but that it had not been "in the name of the Doctor." (TV: The Name of the Doctor)

Behind the scenes

If this individual is an actual incarnation of the Doctor (and not a copy or a manifestation of some part of the Doctor's personality), then Hurt, aged 73 when he first appeared on screen, becomes the oldest actor to portray the Doctor upon their debut, replacing William Hartnell, who was 55 when the show premiered in 1963.