Shuri Ken was a martial arts teacher at the Heishi Clan schools. After being saved from certain death by Jin Mori, he agreed to help Jin hide the cursed blade Shingase and flee Mizen.
After tracking down those responsible for the curse on the Heishi Clan, The Black Syndicate, Shuri attempted to hunt them down to get justice for his master. Instead, he was defeated, and his wife and son were killed by the Syndicate to teach him a lesson.
In pure desperation and despair, Shuri took up Shingase and used the power of the blade to take his vengeance. With nothing left to lose, he began a years-long quest to infiltrate and destroy the Syndicate from the inside.
Shuri joined the Syndicate as an assassin, taking on a new identity, and killing innocents and gang members alike to climb through their ranks, all the while becoming more tainted by the cursed blade.
He became known as the Shadow of Cauldron, a hitman so fearsome and elusive, that his very existence is questioned by many.