Ryuuma is said to be undefeated in his lifetime.
He cut down Pirates who sought the treasures of Wano and defeated invaders who wanted to conquer it one after the other. Thus there wasn't a person who didn't know of the swordsman, Ryuuma, his name echoed throughout the world, the Samurai of Wano Country.
“To catch up to his legend, various sword styles were created in the Wano Country, many of which are secret techniques that were forbidden to outsiders. One of them can cut strong iron, one is said to be able to cut through the flame of dragon. It’s been Several hundreds of years since Ryuma’s death. Perhaps a strong samurai who people can called the ‘second Ryuma’ has already been born.
Strange rumors regarding Ryuma have been spreading around in recent years, it is said that the body of the master swordsman Ryuma and the national treasure meito Shusui has been stolen by someone. 23 years ago, when a certain pirate was causing commotion in the Wano Country, Ryuma’s grave was desolated and the sword and his body disappeared. No one knows the whereabouts of the body and sword, and the samurais who respect Ryuma went searching frantically for the criminal who did it.”