This article contains spoilers for One Piece chapter #1056
Some of the earliest villains that the Straw Hat Pirates faced during their adventures in One Piece are teaming up to become Luffy's next rivals in the race to become the new Pirate King. Buggy, now known as "the Genius Jester", has formed a powerful organization called Cross Guild that includes two of the strongest enemies faced by Luffy and his crew, the former Warlords of the Sea, Crocodile and Dracule Mihawk.
Buggy is the first real villain that Luffy had to defeat during his adventures. After that, the character kept showing up in the most unlikely situations, and he gained major recognition as a pirate mostly due to his luck and ability to be in the right place at the right time. Crocodile, on the other hand, was the first major villain that the Straw Hats faced on the Grand Line, a powerful former pirate who was scheming to take over the country of Arabasta. Finally, Mihawk is known as "the strongest swordsman in the world", and he is the chosen rival of Zoro. When he first showed up, he gave the Straw Hat swordsman his worst defeat, leaving him half-dead and giving the crew the taste of how powerful their future enemies would be.
In chapter #1056 of One Piece, readers finally learn how Buggy was able to get One Piece's coveted title of Yonko and be recognized as one of the most powerful pirates in the world. Despite lacking personal strength, Buggy was able to bring in his new organization, Cross Guild, two fearsome pirates such as Crocodile and Mihawk. Just like Trafalgar Law says, if he is able to command powerful men like them, then Buggy is worthy of the title of Yonko.
There is still a lot to be explained about Cross Guild. Buggy could not be the leader of the group, but the poster showing his face above the other two makes it look this way, and it would be typical of Buggy to take someone else's merits. However, it is also true that Buggy should not be underestimated. He was an apprentice on the ship of the legendary Pirate King, Gol D. Roger, and he behaves as he is on equal terms with Shanks, currently One Piece's most wanted pirate in the world. While he is mostly treated as a comic relief character, Buggy has all the resources to become Luffy's next rival, especially now that Crocodile and Mihawk are in his group.
It is very likely that Buggy took advantage of the World Government disbanding the Seven Warlords of the Sea to gather some former members of the group under his banner. It is also interesting that Buggy, Crocodile, and Mihawk all have history with the Straw Hat Pirates. Buggy and Crocodile might want to settle their score with Luffy, while the confrontation between Zoro and Mihawk has to happen at some point before the series ends. With such an interesting premise, Buggy's team-up of classic One Piece villains promises to be a thorn in Luffy and the Straw Hats' sides.