In the latest chapter Kawamatsu is freed and he makes his first visible appearance.
During the fight between Queen and Big Mom, Kawamatsu’s cell was damaged.
Some guards attempted to kill him, but Kawamatsu kept them at bay by spitting fishbones until Raizo tossed him his katana and the key to his handcuffs.
After freeing himself, Kawamatsu repelled the remaining guards and went into the clearing, where he joined Raizo, Kikunojo, Hyogoro, and Monkey D. Luffy.
Kawamatsu is considered by Kin’emon to have been one of Oden’s most powerful followers, being worth 100 men in battle. As a Yokozuna, Kawamatsu is stated to be the strongest sumo wrestler in Wano. Kawamatsu is also one of the most powerful samurai of Wano.
He wields a katana named Soto Muso, with immense strength and skills. He calls his style the Kappa Sword Style, which appears to combine his swordsmanship and sumo physicality to create rushing attacks that overpower opponents.
