Bored with a life of wealth and privilege among the aristocracy, Raleigh's criminal mind blossomed when he discovered a life of piracy. Raleigh quickly became addicted to crime, which got him noticed by the Fiendish Five. His genius for designing evil machinery also won this crime addict his place in the Fiendish Five.
As part of The Fiendish Five
After the attack on the Cooper home, Raleigh took off with the notes of Rioichi Cooper.
Years later, he had established himself near the Isle O'Wrath, situated in the center of his artificially created Welsh Triangle. Using his storm machine, he caused ships to crash, allowing him to loot them for treasure. Boarding the machine, which was contained in a blimp, Sly confronted Raleigh. Raleigh mocked Sly, saying that he and the rest of the Fiendish Five should have "finished the job" when he helped slaughter Sly's parents. Raleigh then swallowed special bees and bloated to gargantuan size, previously stating that he would "crush Sly like the insignificant bug that he is". Raleigh fought Sly on retracting platforms within the command centre of his blimp.
Despite his powerful attacks, Raleigh was beaten. Still conscious, Raleigh warned Sly of the dangers that awaited in Mesa City, where Muggshot resided. He began claiming that not even a snake could slither in without setting off alarms. Right on cue, Carmelita Fox arrived to arrest him and his crew, ending the legend of the Welsh Triangle.
- Sir Raleigh only appears in the first game of the Sly Cooper franchise, but can also be seen in a cell at Heathrow Penitentiary in the second issue of The Adventures of Sly Cooper comics.
- Along with Ms Ruby, Sir Raleigh is the only member of the Fiendish Five not to reappear in any of the subsequent games of the franchise.
- Pages of The Thievious Raccoonus kept by Raleigh include a pick-pocketing technique from Sally Cooper and Bruce O'Coop's computer hacking technique.
- The newspaper article detailing Raleigh's arrest by Carmelita Fox is titled "Hot Chick with gun busts Amphibian Yuck Mouth".