Shusui in One Piece

Shusui, originally owned by Shimotsuki Ryuma, was a prized national treasure buried with Ryuma in Wano Country. It transformed into a "black blade" after numerous battles alongside Ryuma. Gecko Moria stole Shusui and Ryuma's body 23 years ago, causing shock in Wano.

In the Thriller Bark Arc, Ryuma wielded Shusui as a zombie and later passed it to Zoro after being defeated. In Dressrosa, Kin'emon aimed to return Shusui to Wano. The sword was briefly stolen by a dwarf named Wicca, but Zoro reclaimed it.

During the Wano Country Arc, Zoro was accused of attacks and sentenced to seppuku, with Shusui taken by a corrupt magistrate, Toyama Tsujigiro. Zoro exposed the magistrate and regained Shusui, but it was later stolen by Gyukimaru and returned to Ryuma's grave.

To keep Shusui in Wano, Kozuki Hiyori offered Enma as a replacement, which Zoro accepted.

Shusui is a black katana with a white wavy line along the blade and a flower-shaped handguard. The hilt is wrapped in black silk, and the gold details on the hilt, handguard, and end cap match.

The sheath is black with dark red circles. It has a traditional look with a saw-like pattern on the sides and a dark purple hamon. After the Thriller Bark Arc, Zoro added a sageo rope to the sheath.

Shusui is one of the world's finest swords and Wano's national treasure. Known as Shimotsuki Ryuma's signature sword, it became a permanent Black Blade. Zoro remarked on its durability, noting it wouldn't bend even if stepped on by a Dinosaur. Ryuma even used it to effortlessly behead an enormous Dragon once.

Heavier than Yubashiri, Shusui enhances the wielder's destructive power. In Zoro's hands, it demonstrated increased strength, capable of deflecting powerful attacks and producing giant flying slashes. Zoro considered it crucial for facing Kaidou and the Beast Pirates in the Onigashima Raid.

Shusui, despite its power and weight, initially posed challenges for Zoro due to its tendency to cause excessive destruction and its heavier nature compared to his previous sword. However, after two years of training with Dracule Mihawk, Zoro overcame these issues, and Shusui became his favored blade.

Enhancing Zoro's One Sword Style, Shusui showcased its newfound effectiveness by effortlessly cutting a massive galleon ship and decapitating Dragon Number Thirteen. In the Dressrosa battle, alongside Sandai Kitetsu and Wado Ichimonji, it easily cut through Pica's stone golems.

These hardened swords also successfully wounded the Executive Officer, who had grown to the size of an Ancient Giant, and even after Pica used Busoshoku Haki to fully harden himself.

• Oda drew Zoro's swords personified in SBS Volume 92; Shusui had a long face and thin mustache.

• In Chapter 599, Shusui's sheath resembled Law's Kikoku, possibly an error corrected in the anime.

• In Chapter 937, Gyukimaru said Shusui "became" a black blade with Ryuma.

• In Chapter 955, it's suggested Shusui could've been a Ryō Wazamono before becoming a black blade.

• In the ONA adaptation of "Monsters," Ryuma's sword looks like Shusui.