Twelfth Doctor

The Twelfth Doctor was the first incarnation of the Doctor in a new cycle of regenerations granted by the Time Lords.

Biography
The Eleventh Doctor died of old age after spending many, many years on Trenzalore protecting Gallifrey and the planet. The Doctor was on his last regeneration, but the Time Lords granted him another life. Shortly after regenerating, this Doctor voiced his surprise at having new kidneys, and his inability to fly the TARDIS, much to the shock of Clara Oswald. (TV: The Time of the Doctor)

At some point in his travels, he joined his previous selves in helping place Gallifrey in a pocket universe at the end of the Last Great Time War. (TV: The Day of the Doctor)

Behind the scenes

 * Like the War and Ninth Doctors, the Twelfth Doctor unusually debuted on television before his regeneration from his predecessor was screened.
 * His first words — "Kidneys! I've got new kidneys!" — keep to the modern tradition of new Doctors immediately commenting on their bodies. Previously, the Tenth Doctor commented on his "new teeth", (TV: The Parting of the Ways) and the Eleventh on his legs. (TV: The End of Time) Past Doctors had similar comments later on. (TV: Robot, TV: Doctor Who, TV: Rose)