I give credit to @Celestial D. Dragon for making this theory in spoiler thread.
So according to him, Buggy becomes a Yonko after getting the only Ancient Weapon which whereabouts is still unknown, Uranus.
How did Buggy find it?
It is from Captain John's treasure mark that Luffy gave him in Impel Down arc. The map shows the location of the treasure, and the treasure turns out to be Uranus.
Buggy accidentally found an Ancient Weapon while looking for treasure, by sheer luck, which is the ongoing theme for Buggy's character.
Then this evening, I found sanjikun's post:
He pointed Buggy became Shichibukai, all indirectly caused by Luffy.
Then this time, he becomes a Yonko, probably all because of Luffy too: giving him the treasure map in Impel Down.
I think Celestial's theory of how Buggy became a Yonko can happen. Instead of the other theories like "Weevil / Mihawk / other strong characters join Buggy so now he becomes a Yonko." The gaining strong crewmembers card has been used to promote him into Shichibukai, so I don't think it will be used again to promote Buggy to a Yonko.
Extra Part: Buggy's Bounty
I am 80% sure that Buggy's current bounty is above Luffy/Law/Kidd's 3 billion bounty.
This is the reason why World Government didn't pick neither Law or Kidd as the new Yonko. If Buggy is lower than them, then logically the 4th Emperor will be Law, the silver medalist in Wano. Luffy was picked and not Law nor Kidd because Government knows Luffy is the ringleader while the other 2 are acting like his cheerleaders.
Yet they pick Buggy over those 2 (for reason stated above: in possession of Ancient Weapon has higher threat level than defeating 1 of the previous Yonko).
So Luffy currently has lowest bounty among the Yonkos and Buggy is at least at the 3rd rank, if not higher.
Tagging
@Echizen_Jo_Ndule @m0nst3Rx @Fleet Admiral Lee Hung @AkainuTheGrimReaper @nik87 @comrade @Jailer @Hades @TheAncientCenturion @Sentinel @Tyki_Mikk @Steven @Salah WG @Pantheos @uyuu @Chrono etc.
So according to him, Buggy becomes a Yonko after getting the only Ancient Weapon which whereabouts is still unknown, Uranus.
How did Buggy find it?
Buggy accidentally found an Ancient Weapon while looking for treasure, by sheer luck, which is the ongoing theme for Buggy's character.
Then this evening, I found sanjikun's post:
If you think about it, all of this is because of Luffy. He's the one who sent Buggy to Impel Down. He's the one who got him out and put him in MF.
Then this time, he becomes a Yonko, probably all because of Luffy too: giving him the treasure map in Impel Down.
I think Celestial's theory of how Buggy became a Yonko can happen. Instead of the other theories like "Weevil / Mihawk / other strong characters join Buggy so now he becomes a Yonko." The gaining strong crewmembers card has been used to promote him into Shichibukai, so I don't think it will be used again to promote Buggy to a Yonko.
Extra Part: Buggy's Bounty
I am 80% sure that Buggy's current bounty is above Luffy/Law/Kidd's 3 billion bounty.
This is the reason why World Government didn't pick neither Law or Kidd as the new Yonko. If Buggy is lower than them, then logically the 4th Emperor will be Law, the silver medalist in Wano. Luffy was picked and not Law nor Kidd because Government knows Luffy is the ringleader while the other 2 are acting like his cheerleaders.
Yet they pick Buggy over those 2 (for reason stated above: in possession of Ancient Weapon has higher threat level than defeating 1 of the previous Yonko).
So Luffy currently has lowest bounty among the Yonkos and Buggy is at least at the 3rd rank, if not higher.
Tagging
@Echizen_Jo_Ndule @m0nst3Rx @Fleet Admiral Lee Hung @AkainuTheGrimReaper @nik87 @comrade @Jailer @Hades @TheAncientCenturion @Sentinel @Tyki_Mikk @Steven @Salah WG @Pantheos @uyuu @Chrono etc.

