Twice Upon a Time (Doctor Who) The Doctor paraphrases philosopher Bertrand Russell when he advises his future self that "hate is always foolish and love is always wise". Peter Capaldi reprised his role as the Twelfth Doctor. On 30 January 2017, he confirmed that the tenth series would be his last, and that he was set to leave after the 2017 Christmas special. The episode also sees the introduction of Jodie Whittaker as the Thirteenth Doctor, whose casting was announced on 16 July 2017. David Bradley appears in the episode as the First Doctor, having previously portrayed William Hartnell in the docudrama "An Adventure in Space
Eternal (Doctor Who) Eternal (Doctor Who) The Eternals are a race of cosmic beings first introduced in the "Doctor Who" TV adventure "Enlightenment" with the 5th Doctor (Peter Davison) in 1983. An Eternal who called himself Striker explains to the Doctor that he and his people live outside of time, in the realm of eternity. They consider the mortal inhabitants of the universe to be "Ephemerals", including even the Time Lords of the planet Gallifrey. Striker seems completely unaware of the existence of the Time Lords before meeting the Doctor. In the "Enlightenment" serial, the Doctor eventually realizes that the Eternals are powerful