War Doctor (PhantomLord2001)

The War Doctor, also known as The Renegade or The Warrior, was the ninth incarnation of the renegade Time Lord known as The Doctor, and the only incarnation to not be primarily known by that name. This incarnation abandoned the title of "the Doctor" and, for nearly the entirety of his life, fought as a soldier on the front lines of the Last Great Time War. He participated in many battle and engagements in the War, but would eventually grow weary of the war. In his own words, the war was "non-stop carnage. No matter what I do, this war produces more death and destruction. No more."

Towards the end of the war, the War Doctor stole the Moment from Gallifrey's Time Vaults, and intended to use to end the Time War by committing genocide against both the Daleks and his own people. After viewing his own future, this incarnation helped to save Gallifrey from destruction, although he was not able to retain these memories. Because of this, his later incarnations disowned him, believing him to have destroyed Gallifrey. The Eleventh Doctor would retain the memories, and eventually remembered him as the man who saved Gallifrey. (TV: The Day of the Doctor)

This incarnation eventually regenerated due to advanced old age, shortly after he had saved Gallifrey. He remarked before regeneration that he was "wearing a bit thin," a nod back to the regeneration of the First Doctor.