One Piece is a series famous for the allure of its fascinating world. Most fans of the series agree that when it comes to world-building, no one comes close to the talents of Eiichiro Oda, as he is a master at filling this world with tons of interesting and mysterious aspects that leave the fans guessing and theorizing about them indefinitely, only for them to be shown later on in a reveal that shakes the foundations of what everyone knew.