The Wano Country is a country not affiliated with the World Government and is currently occupied by the Beasts Pirates.
Government’s Plan to “Acquire” Wano & The Shichibukai Connections To Wano
Wano is most likely the only country other than Elbalf that is known to be so immensely powerful that the Marines tend to stay away from it. So the Reveire could decide to send the Shichibukai to stop Kaido and the Shogun.
Who will agree to this?
Well, all of them:
#Dracule Mihawk
Mihawk is the “Greatest Swordsman in the World” and was Shanks’ rival before Akagami lost his arm. I believe that he’s Yonko-Level. Mihawk will agree to fight anyone but “Red Haired” Shanks.
#Edward Weevil
His powers have been praised by Kizaru who compared his abilities to that of a younger Whitebeard, his alleged father. He was able to single-handedly defeat 16 pirate crews affiliated with Whitebeard, including the A.O Pirates, without taking a single injury. If he learns that Wano is Luffy’s next stop he’ll agree too.
#Bartholomew Kuma
Kuma is one of the few people to have completely defeated the Straw Hat Pirates, and is also the only character introduced so far that has defeated the crew single-handedly, twice. He will agree since he’s fully under the Control of the World Government.
#Boa Hancock
Boa Hancock is widely considered to be extremely powerful by friend and foe alike. She will agree since Luffy will also be at Wano.
#Buggy
Legend. As Shichibukai he will just follow WG orders. With that massive crew he wouldn’t have second thoughts to go to Wano, he might plan to recruit a few Samurais for business.
Why it is absolutely necessary for all 7 Shichibukai to be present
“The balance between 3 Great Powers has fallen into a terrible state, how will we go about filling the 3 empty seats in the Shichibukai”
They most likely found 2 new people for the rank as filling these seats was their no.1 priority once. But I can say for sure that they will fill all the seats sooner or later and before Wano we might see a Shichibukai Meeting:
So after the Reverie a Shichibukai Meeting could take place to select 2 new people for the vacated positions and for the Wano takeover mission.
What about the former Shichibukais?
#Sir Crocodile
He might have tracked Pluton down to Wano and since Wano is already being taken over by Kaido he would most likely try to locate it through Kaido. So he could ally with Kaido to gain access to it.
#Gekko Moriah
He wants revenge against Kaido.
#Donquixote Doflamingo
He was too confident when he went to prison…he could have already planned his escape. Wano being taken over is something that has to be stopped at any cost and Doffy is the one person who holds information on Kaido’s plans, strength and influence.
The world nobles fear the loss of their power and influence and Doflamingo’s cryptic message was that they would lose it which means as soon as Kaido gains Wano he could be coming to destroy everything.
So Doflamingo gives everything up on Kaido and negotiates release.
He could also propose to go to Wano with the other Shichibukai.
#Marshall D. Teach
He will be in Wano ready to steal Road Poneglyph and Devil Fruit from Kaido.
*Theory by King of beasts kaido