"Did you find him?"
"Marvelous, what is his name?"
The Doctor was a Templar soldier during the events of Assassin's creed 2 and Brotherhood
The Doctor started out as a pickpocket who had a gift for creating medicines, gases and Poisons. He then became a Templar assassin.
As time went on he created far more deadly Poisons. He was given an enormous task by the Templars: to create an Assassin that would serve the Templars unquestionably. He sent out to find one and discovered that his best friend would be suitable for the job. In the night he drugged his friend and took him to his hideout. Once there he wiped his memory and brainwashed him.Once his friend awoke he named him: The Prowler.