The One Piece Thunder God Chronicles

An ordinary university student from Blue Star accidentally transmigrates to the world of pirates. After Luo Chuan arrives in the pirate world, Garp takes him back to Marine Headquarters. He swears to live another life entirely on his own terms. What's most important if you want to do everything your own way? Strength! Strength! And more strength so overwhelming it leaves people in despair! The Marines are lapdogs of the World Government? Then why not make the Marines independent? Garp: If you put it that way, I might just agree to become an admiral! Sengoku: Luo Chuan is the hope of the Marines' rise. Whether we can uphold true justice depends on him.