The Doctor (The Cabinet of Light)

An incarnation of the Doctor helped Honoré Lechasseur defeat Mestizer.

Biography
The Doctor regenerated after being shot in the back by Mestizer in the London docks. He spent several months lying low while Honoré Lechasseur conducted his investigations for him. (PROSE: The Cabinet of Light)

Under the alias of Dr Smith, he tried to stop the Sodality from existing, so that hundreds of time sensitives would not be killed by them. After failing to gain the support of the High Executioner in erasing the Sodality from history, the Doctor departed in his TARDIS.

The Doctor set events in motion so the "Child of Time" would gain its full powers and stop the Sodality's plans. The Doctor left in his TARDIS with the unconscious High Executioner, who was now suffering from amnesia. The Doctor dropped off the High Executioner in 1949, where she called herself by her real name, Emily Blandish, and helped the Doctor defeat Mestizer in his relative past. (PROSE: Child of Time)

Personality
The Doctor smoked to improve his singing voice. He had recently lost a travelling companion, which made him reluctant to take on a new one. (PROSE: The Cabinet of Light)

Appearance
The Doctor wore a black coat with green collar, white shirt, a loose collar on the coat, exposing his neck and pronounced throat. He wore a hat and muffler. He was clean shaven on only his chin and lip and had brown hair which was receding. He was gangly but not too tall and had large hands. (PROSE: The Cabinet of Light)

Behind the scenes

 * There is a similarity between the Shalka Doctor and this incarnation of the Doctor. However such a similarity is entirely coincidental, as author Daniel O'Mahony worked on this story with no information that a new incarnation of the Doctor would be introduced just months after the publication of his novella.
 * In AHistory, Lance Parkin considers that this incarnation of the Doctor could be a result of the Sodality's alternate future and not actually have been from the "main" timeline.