One Piece: I am the swordsman Ryoma

Story of: One Piece: I am the swordsman Ryoma

Ryoma wakes up from time travel and finds that he has become an ancient dragon-slaying samurai swordsman. He has obtained the system. At the beginning, he kills Moonlight Moria, one of the Shichibukai, and obtains the S-level Shadow Fruit!Doflamingo: "Is it really that ancient Ryoma who interrupted my plan to sell devil fruits?" Akainu: "This bastard, I didn't expect it to be so difficult. He took Kaido's position and still didn't join. Franchise country!"... From then on, Ryoma continued to absorb Devil Fruit abilities, learn stronger combat skills, and reach the top!Ryoma: "Those who invade my country will be punished no matter how far away they are!"