Rupert Martin was a resident of London during the mid-18th century.
On 18 April 1754, the Templar Haytham Kenway murdered the Assassin Miko at the Theatre Royal and stole the Grand Temple Key from the latter. Around the same time, Rupert boarded the Providence, a merchant ship, intending to migrate to the Thirteen Colonies.
Aboard the ship, he met Haytham, unaware that he was the murderer. As Haytham feigned ignorance of the murder, Rupert explained that it was still under investigation. As Haytham asked about the motive, he told him that robbery had been ruled out by investigators. It was speculated that a business arrangement had gone wrong, or that the murder had been committed for shocking personal reasons. Rupert noted that he was glad to be away from the increasingly dangerous city.