Oden Two Sword Style, otherwise known in Japanese as "Oden Nitoryu," is a way of swordsmanship devised by Kozuki Oden, the legendary samurai from Wano Country and former Daimyo of Kuri. This style focuses on dual-wielding two legendary swords, Enma and Ame no Habakiri, with greater Haki techniques applied to improve its combat potential.
Kozuki Oden was the greatest user of this style, and it shows in his fights, portraying incomparable strength in both swordsmanship and fighting. The focus that comes first in the Oden Two Sword Style is emission-like level Armament Haki: projection of their Haki from the body to the blades. The technique does allow a swordsman to deal huge damage without touching an opponent. This ability is otherwise granted only to a few characters in the One Piece world, among them Zoro and Mihawk.
The Oden Two Sword Style has some strong techniques in its arsenal, most conceived with the special ability of both Enma and Ame no Habakiri in mind. However, Enma is especially infamous for the absurd amount of his user's Haki that it draws out. This makes it a very difficult sword to use but incredibly strong if an expert swordsman gets to wield it. Ame no Habakiri, also known as "Feathery Cutter of Heaven," compensates for Enma's weakness with its sharpness and sturdiness.
Probably one of the most great moments when Oden's Two Sword Style was shown was his legendary battle against Kaido, one of the future Emperors of the Sea. In this battle, Oden did manage to leave a permanent scar on the otherwise completely impervious Kaido, which showed just how extremely powerful his technique of dual-wielding could be. This battle cemented his reputation as probably the greatest swordsman who ever existed.
Kozuki Oden's style was unique, and he has left a permanent mark on Wano and everywhere else. His techniques and the legend of his swords move down to the future generation, more especially to his retainers and children. His son, Momonosuke, and his retainers, the Nine Red Scabbards, work hard to uphold the ideals of Oden, especially Kin'emon and Denjiro, to master his techniques in their quest to take back Wano from the tyranny of Kaido.
Eventually, Roronoa Zoro inherits Enma from Hiyori, Oden's daughter. His initial struggle to master the huge power of Enma parallels that of Oden himself with the sword. This not only cements Zoro's growth as a swordsman but also aligns him with the eternal legacy left by Oden. While Zoro is adapting to Enma in his fighting style, he is using bits of Oden's techniques that make his fighting capabilities even more efficient.
Oden Two Sword Style thus comprises powerful and picturesque techniques. Coupled with the Emission-level Haki previously mentioned, Oden used a great deal of named attacks that brought out the full potential of dual-wielding. Often conducted in synchronization with both swords, these give a combination of speed and accuracy together with raw strength that can easily overwhelm even the most powerful opponents.
What is unique about Oden in his style is the origin of his learning. Unlike traditional Wanoan swordsmanship, most of Oden's techniques came about independently, as a result of his adventurous spirit and desire to explore beyond the confines of his homeland. So, in a way, his approach toward swordsmanship was not about upholding conventions but about innovation and effectiveness. This makes his styles really formidable and quite unpredictable.
The last-standing dreams of Oden live with the continuous struggles of his retainers and descendants. His techniques, rediscovered and put to use, become a metaphor for the struggle of freedom and justice in Wano. Through the story of One Piece, Oden Two Sword Style remains the epitome of eternal strength, resilience, and the inexorable willful nature that defines the samurai spirit.