Summary:
Kawamatsu tells the story of him and Gyukimaru, revealing that Gyukimaru was actually a fox named Onimaru. Hiyori offers Enma Zoro in exchange for Shusui.
Zoro chases after Gyukimaru, but walks into an old door and disappears. Hiyori and Kawamatsu decide to go together, but are attacked by another wave of bandits. Kawamatsu fights them and explains what happened after he lost Hiyori.
Thirteen years ago, after Hiyori ran away, he decided to leave Ringo. Ringo was a region formerly ruled by the daimyo Shimotsuki Ushimaru, who was in the company of the fox Onimaru. However, when Orochi overthrew Oden, Ushimaru was killed and Ringo fell.
Kawamatsu found a mass grave with Eternal Graves. These corpses were buried in coffins and did not decompose due to the cold. They were marked with the sword of the deceased, which was said to contain the soul of the deceased. These swords became attractive to grave robbers, but the cemetery was guarded by the fox Onimaru.
Onimaru was initially hostile towards Kawamatsu, but eventually warmed to him. After seeing Kawamatsu take the swords from the graves, he became hostile again. Kawamatsu explained that the swords were to be used for the upcoming raid on Onigashima. Since samurai swords would aid their wielders in battle, Onimaru allowed him to do so and helped him collect the other swords.
Together they built a hideout to keep their swords, stole food from the capital to feed themselves, and defeated all the grave robbers when they took their swords. Unfortunately, when Kawamatsu tried to steal some tofu one day, he fell into a trap and was arrested and sent to the Udon Prison Mine.
In the present, Kawamatsu goes to the place where Gyukimaru disappeared and discovers that it is where the swords were placed. He contacts Kin’emon and tells him that he has a supply of swords needed for the army. It turns out that Gyukimaru was the one who arranged the swords while Kawamatsu was away, as it was actually Onimaru in his human form. He transforms back into his fox form and leaves, his duty accomplished.
Zoro tries to take Shusui back, but Hiyori asks him to let it go. Hiyori offers him a replacement sword, Enma. This sword belonged to Oden himself and is the only sword that has ever successfully injured Kaido.
The anime adds the following:
Zoro sees Gyukimaru opening the entrance to the secret place where the weapon stash is kept.
Kawamatsu defeated another group of Beasts Pirates after Zoro ran after Gyukimaru.
In a flashback, the scene shows Kawamatsu preparing to end his own life until he hears Onimaru fighting a group of Beasts Pirates.
The scene where Kawamatsu builds the cave where he kept the swords.
Kawamatsu is shown being arrested by Orochi’s enforcers.
In the manga, Kawamatsu was caught by a crowd of people. In the anime, Kawamatsu is caught in a net.
Who’s Who, Sasaki and Page One in his human form are shown in silhouette.
However, Who’s Who’s appearance in Kawamatsu’s flashback is non-canon, as the manga later revealed in chapter 1017 that he was not connected to Kaida 13 years ago, which was due to him being part of CP9 at the time.
The scene of Kawamatsu and Onimaru reflecting Bingo, Bongo and Bungo is extended.
A scene of Oden injuring Kaidou is shown later in the manga.