- Ah Tabai: "Where is the Assassin, Duncan Walpole?"
- Edward: "Dead and buried, after he tried to kill me."
- Ah Tabai: "We are not sorry to see him gone, but it was you who carried out his final betrayal."
- —Ah Tabai and Edward Kenway discussing Duncan Walpole's betrayal and fate, 1716.[src]
Duncan Walpole (1679 – 1715) was a Master Assassin of the British Brotherhood of Assassins, who, around 1715, attempted to defect to the Templar Order. During his time in the Caribbean before his betrayal, he briefly trained under Assassin Mentor Ah Tabai. He utilized this period of time to gather valuable information about the locations of various Assassin bureaus in the area.
In June of 1715, the Royal Navy warship carrying Walpole, the HMS Intrigue, identified and attacked a pirate brig, the Jacobite, captained by Bramah. The pirates managed to de-mast the frigate, but soon found that their own weapon magazine had been hit. Boarding the ship, Walpole assassinated the captain, but was thrown overboard by the magazine explosion.
Shipwrecked in Cape Bonavista, Cuba, Walpole attempted to enlist the aid of the only other survivor - the pirate Edward Kenway - in reaching Havana. Edward attempted to haggle the price of passage, but Duncan threatened him with a flintlock pistol in response, only to find that it was unable to fire due to wet gunpowder. Walpole subsequently fled into the jungle, and Edward gave chase before eventually dueling and killing him.
On Duncan's corpse, Edward found a letter from the Spanish Governor of Cuba, Laureano de Torres y Ayala, referencing the cargo Walpole was bringing to him: a blood vial and maps pertaining to the locations of Assassin bureaus across the Caribbean. Edward chose to assume Walpole's identity and collect the reward himself.
- Duncan Walpole was the second cousin of Robert Walpole, 1st Earl of Orford, the generally-recognized first Prime Minister of Great Britain and an eventual acquaintance of Edward Kenway.