If the last island in the Grand Line is Raftel.... What's behind that?
Why, the Beyond Gold of course!! The Beyond Gold's name is a reference to the fact that it is beyond Raftel, the legendary site of One Piece. The ocean's official name is the Typhoon Tropics, people know it as the Beyond Gold Ocean, or simply, Beyond Gold. But the pirates, bandits, revolutionaries, and bounty hunters aren't concerned with such a trivial amount of treasure like the One Piece. The pirates here are more intense than the New World, keep in mind they had to have made it past Raftel. The hero Gold Roger, the one hailed as the Pirate King, could only make it up to Raftel, not past it. To these criminals, the One Piece treasure that sparked an era of rebellion seems like a waste of time. These men and women are hardcore, and as such, the World Government stands no chance at all in these rough seas. The criminals here run the place pretty much, since nobody, not even Whitebeard, has the power to stop them.
The World Marines, suffering a defeat at the hands of Whitebeard, needed to redeem themselves. That is, until the World Enforcers took control of the military. Heartless brutes loyal to Mariejois, the World Capitol, took power and killed off the Marines. Now, some escaped, but they were faced with a choice: Death, or Impel Down for life. They chose piracy. It was their only choice if they wanted to live, as no doubt they'd be on death row for losing the single most important battle in World history. Those marine-pirates, along with other original pirates, now allies, such as Smoker's crew, Garp's crew, Luffy's crew, and Whitebeard's crew escaped the strict jurisdiction of the government. Even such powers as the Shichibukai, the Yonkou, the Eleven Supernovas, and the Marine Admirals were driven into the Beyond Gold if they wanted to live. Turns out, the One Piece "treasure" was Ace. The son of Roger. And Whitebeard is in possession. In truth, since every Beyond Gold criminal knew the treasure was not an actual treasure, the name of thier sea is a misnomer, but the name stuck. However, it's all good and fine now they escaped from the Gorousei's evil jurisdiction, the World faces a new threat. Gol D. Rush, the twin brother of the Pirate King, takes charge of the Beyond Gold, with his crew as the new dictatorship of Beyond Gold. Twenty years after Rush took power, Luffy is the Pirate King, Whitebeard has passed away with Ace inheriting his crew, and Rush was assassinated by an unknown man called Genocidio. The evil dictatorship of a man who's name literally means "Genocide" takes office. And who can stop it? Nobody but the largest pirate crew alliance in the world: The Straw Hats.