Granddad took over from the Eighth Doctor to fight in the Time War and was played by based John Butthurt from 2013 - 2013 (2017 if you count ear stories) and voiced by David Hayter in his debut game Metal Gear Who 3: Splink Eater.
"Doctor Who has changed... It's no longer about creative storytelling, science fiction or interesting situations. It's an endless series of half baked stories and pandering to demographics that don't exist. Doctor Who, and its consumption of tumblr fandom, has become a well olied machine. Doctor Who has changed, Whovian redditors, wearing Whovian fezzes, using Whovian tumblr slang. Tumblr blogs about patriarchy and misogyny enhance and regulates their victimhood, Canon control, creative control, emotion control, everything is monitored and kept under control. Doctor Who has changed, the age of series arcs has become the age of tedium, all in the name of plot twists everyone saw coming. And he who controls the canon, controls history. Doctor Who has changed, when the show is under Moffat and Rusty, bad storytelling becomes routine. "
Knowing he had no chance of writing something good, Moff instead inserted a previously unseen War Doctor in between the Eighth and Ninth Doctors who isn't really the Doctor because he did a naughty thing (blew up Gallifrey and killed billions of children in the process.)
However The Day of the Doctor retconned all that lovely genocide and changed it to putting Gallifrey into a nice neat pocket universe. So really the War Doctor never blew up Gallifrey and probably is the Doctor after all. But he wasn't important enough for a number. So he's just War Doctor, or War for short.
John Motherfucking Hurt Edit
War was played by John "I'm Too Good for This Show and I Know It" Hurt in The Name of the Doctor, The Night of the Doctor and The Day of the Doctor.
How the fuck Moffat got Hurt to slum it up in this is a mystery to all. He spends the whole thing
phoning it in acting through full-blown, not-in-remission, painful-as-fuck cancer, and still manages to make Tennant and Smith look like they wandered in off the set of a preschool production of The Three Little Pigs.
Seasons of War Edit
A less than canon collection of stories about War, called Seasons of War, is being put together by some pretty cool people, and giving the money to charity or some shit.
The only downside is War looks like a lesbian for some reason beyond human comprehension.
Known aliases include: Granddad, Old Snake, Pliskin, Chestburster.