Shusui

The Shuusui is one of the 21 Ō Wazamono Grade Swords. It was the named blade of the Samurai Ryuuma, who appeared as a zombie on Thriller Bark that had been given Brook's shadow. Roronoa Zoro was given the sword by Ryuuma after the latter's defeat, saying the sword would be satisfied with Zoro as its master. Its blade is black and its hand-guard has flower-like edges.

Abilities
The Shuusui is designed to increase the damage potential of the user, but Zoro has commented that Shuusui's greatest attribute is its hardness; saying that even if a dinosaur were to step on it the blade wouldn't bend.

While it deals a heavy blow and is extremely hard, Shuusui has a few major problems of its own. Just as Sandai Kitetsu turned out to be a "problem child", Zoro describes Shuusui as having a "temper" that makes it harder to wield. In comparison to Yubashiri, which was extremely light, Shuusui is extremely heavy.

While in the hands of Ryuuma, this sword was used by him in both life and death. As a zombie who was imbued with Brook's shadow, Ryuuma has acquired the Fencing Style. Coupled with his already powerful skills, the modifications made to the zombie body, and the powerful attributes of the Shuusui, the Fencing Style has been revamped to the point of being completely different from Brook's original version.

When in the hands of Roronoa Zoro, this sword was used to replace the broken Yubashiri for his Three Swords Style. When first fighting against Oz, Zoro discovered that the Shuusui's heaviness is what attributes to its durability and increased power potentials. However, this weight turns out to make Zoro decrease control over some of his attacks. As time passed, Zoro began to master over Shuusui's negative attributes.