War Doctor
This unknown incarnation of the Doctor was encountered by the Eleventh Doctor and Clara Oswald when they entered the Doctor's time stream on Trenzalore. (TV: The Name of the Doctor)
The Eleventh Doctor, upon coming into contact with this incarnation spurned the very memory of him, going so far as to suggest this incarnation did not even hold the moniker of "the Doctor" due to his actions in life. 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".
This could hint towards The Doctor's actions in the Last Great Time War, and why he is named in the history Clara found in her exploration of the library. (TV: Journey to the Centre of the TARDIS). According to reports they tend to suggest that he is the ACTUAL 9th Doctor, and that the doctors did not want to remember him due to his actions, hence the fact that in fact the 11th doctor is the 12th Doctor and he can only regenerate 12 times, so it's said the doctors time is running out.
