"Enma is one of the 21 Great Grade swords, currently in the possession of Roronoa Zoro as one of his three blades.The sword was crafted by the swordsmith, Shimotsuki Kozaburo in the Wano Country. Until 20 years ago, Enma was wielded by Kozuki Oden alongside his other sword, Ame no Habakiri. In Oden's hands, both blades became the only weapons known to ever (until the present day) injure Kaidou.
After Oden's death, Enma was inherited by his daughter, Kozuki Hiyori, who would later gift the sword to Zoro in exchange for the latter allowing Shusui, a national treasure, to remain in Wano." -One Piece History
The single-pass grommet hole construction creates less friction between strings, this effectively reduces tension loss, while extending string life
Different frame structures including Power-box Diamond, Aero and AeroDynamic are arranged and integrated based on computer simulation to optimize the hitting, frame characteristics, and overall performance.
Inspired by military helicopter, multi-layered structure made by carbon fiber and composites, minimize material size, reinforce handling feel and performance.