The War Doctor is een extra regeneratie die tussen de 8ste en 9e Doctor. De acteur die de War Doctor speelt is niemand minder dan
John Hurt. Het karakter is door Steven Moffat specifiek voor de jubileumaflevering die het 50 jarig bestaan van de serie herdacht, gecreŽerd. In het
Originele script voor deze aflevering wilde hij de negende Doctor laten zien in de laatste dagen van The Great Time War. Moffat was er echter niet zeker
van dat Eccleston zijn rol als de negende Doctor op zich zou nemen, hetgeen ook klopte. Daarnaast was Moffat terughoudend om de achtste Doctor, gespeeld
door Paul McGann, de incarnatie te laten zijn die de Time war beŽindigd. Dus bedacht hij deze incarnatie van de Doctor die nooit eerder genoemd was,
hetgeen hem meer vrijheid gaf in het bedenken van een verhaal.
Moffat wist dat het succes van deze aflevering zou afhangen van de acteur die de rol zou spelen. Deze acteur zou over een voldoende groot kaliber
moeten beschikken en uiteindelijk is gekozen voor John Hurt.
The War Doctor's origins are given in the mini-episode "The Night of the Doctor", set during the Time War referred to in the series. After the Eighth Doctor
(Paul McGann) is killed in a spaceship crash while trying to save an innocent woman, who rejected his efforts because she regards the Time Lords and the Daleks
as equally monstrous for the collateral damage inflicted in the war, he is temporarily resurrected by the Sisterhood of Karn (The Brain of Morbius) and urged
to take a stand and join the war. He is offered an elixir designed to trigger a life-saving regeneration into a form of his choice. Feeling the universe has
no more need for a doctor, he requests to become a warrior. After regenerating into the War Doctor, he disowns the name of the Doctor, with his new incarnation's
first words being "Doctor no more".
In the 50th anniversary special "The Day of the Doctor", having fought in the Time War for many years, the greatly aged War Doctor steals the superweapon known as
"the Moment" with the intent of wiping out all combatants in the war along with his home world of Gallifrey. However, the Moment is sentient, possessing a conscience
that requires the user to morally justify his use of it, and interacts with him in the shape of his future companion Rose Tyler (Billie Piper). Although acknowledging
that she can do what the Doctor asks of her, she then sends the War Doctor into his future to meet the Tenth and Eleventh Doctors (David Tennant and Matt Smith
respectively) to understand the sadness and regret they endured while continuing the good he failed to accomplish. Having witnessed his future selves prevent a Zygon
conquest of Earth and the destruction of London, the War Doctor concludes that he must destroy Gallifrey, reflecting that he is lighting the fire so that better Doctors
can be forged, only for the Tenth and Eleventh Doctors to travel back to activate the Moment with him, the later Doctors declaring that they now recognise the War
Doctor as having been "the Doctor on the day it wasn't possible to get it right". However, aided by the Moment's interface which shows them a vision of the horror
and destruction wrought in the Fall of Arcadia, the last battle the War Doctor fought in, and Clara's plea to remember the vow they made in taking their name, the
Doctors ultimately conclude that the loss of life that would be caused by using the Moment is something they cannot accept. They instead pool their resources, and
with the help of the Doctor's various incarnations, attempt to save Gallifrey by freezing it in a moment in time, creating the illusion of the planet's own destruction.
The Daleks are effectively tricked into firing on each other, annihilating themselves. The War Doctor accepts that upon returning to his own timeframe, he will forget
his own heroic actions and must live with the false knowledge that he killed his own people. Before leaving, he takes a moment to thank his future selves for helping
him "become the Doctor" again. Once inside his TARDIS, he begins to regenerate, realising that his body is "wearing a bit thin," echoing the First Doctor's utterances
in The Tenth Planet.