The Doctor of Loss

The Doctor was an incarnation of the Doctor that existed after the Twelfth Doctor, but before another Doctor, the previous Doctor and the Riley!Doctor.

History
This Doctor watched her companion die, and wrote in her diary about whether she had the right to go back and change history to "fix a mistake." She deduced that she did not, but wondered "how much more" she could take. It is then implied that she did alter the timeline so that her companion never existed. (Perfection)

Behind the Scenes

 * This incarnation of the Doctor is played by Elisa Melendez, who appears with Mikey Neumann on Deep Dive and is also the voice of Tyreen Calypso in Borderlands 3.
 * She is also one of the players in Hot Quest, a Dungeons & Dragons YouTube series GM'd by Ben Paddon.
 * In the Doctor's chronology, The Doctor of Loss is the oldest incarnation of the Doctor not featured in the BBC series. She is also the second past non-BBC incarnation of the Doctor to be revealed.
 * The Doctor of Loss was named as such in the Season 2 Credits released on December 4th, 2020.