Ever wondered why One Piece's story line is scattered right now? I mean, if you observe Oda's storytelling from previous arcs, the Straw Hat Pirates always have a clear goal and a specific group of enemy to defeat per arc. But now, it's confusing to see who they're really gonna go up against.
They went to Fishman Island, they provoked Big Mom.
They went to Punk Hazard and Dresrosa to defeat Mingo, they provoked Kaido.
They meddled with Jack in Zou, they provoked Kaido again.
They screwed Big Mom's tea party (among other things), they provoked Big Mom.
Oda is leading us to assume that they'll first fight and defeat Kaido and then finish Big Mom off. But I think Oda has something else in mind. I believe he is going to create a war between the Big Mom Pirates, Beast Pirates, and the Worst Generation Alliance.
And here's why.
Oda has been carefully linking all the three factions together. First, he tried to make a group of outrageous pirates in Shabondy labeled as the Supernovas and the Worst Generation. He showcased each SN to have an undying will to achieve their goal and have no intention of being or staying under anyone, including the Yonkous.
Let's break it down for all SN except the Straw Hats:
1. Bege - he only went under Big Mom to plot an assassination against her. But we all know how that went down, so now, he's a target of the Big Mom pirates and has no choice but to rebel against them. And of course, because of Morgan, news will come out and no other Yonkou will accept him since he can pull the same thing against them.
2. X Drake - seems to be under Kaido to get close to Joker and get revenge for killing his love ones, but now that's over, I think he's planning to cut ties with the Beast pirates. I mean, it doesn't make sense that an ex-marine will go to the New World just to serve under an Emperor. I'm guessing that because he couldn't touch Joker as a marine, he plotted to kill him using Kaido's connection with him, thus turning himself to piracy. But he knows he's not strong enough, and it's suspicious to join Doffy's group out of nowhere. So he chose to be under Kaido to be stronger, be protected by his name, and to slowly gain trust for him to be sent to deal with Mingo.
3. Apoo - seems to only be under Kaido to survive, because Kaido defeated their alliance by himself and could kill all of Apoo's nakama. Although some people say that Apoo betrayed the Kidd-Hawkins-Apoo alliance from the get go, it kinda seems unlikely. The Beast pirates doesn't seem to be the kind of pirate group to hide their affiliations with anyone. So if Apoo joined, why would they hide it? They're a group that have a similar impulse to destroy and conquer(why else would their three top fighters be called calamities?). We've already seen Jack and his gang do that in Zou. And we've already seen Apoo provoke an admiral in Shabondy, it's hard to imagine that such a pirate would willingly serve under a Yonkou. And why would Kaido of all people bother to come by himself and kick their ass? He could've sent one or two of his calamities and have the same result. So I believe they got beaten first, and was given a choice to either serve under Kaido or be executed.
4. Kidd, Killer and Hawkins - Oda did it again with his genius plot twist, he first led us to believe that their alliance will target Red Hair to distract us from his goal to form an alliance between the worst generation. Now Kidd, Killer, Hawkins, and Apoo has a strong reason to ally with Luffy and Law because they saw how strong Kaido is and how they hate him for beating them and probably killing a few of their nakamas.
5. Urouge - with him allegedly killing one of the sweet commanders, he's a definite target of Big Mom Pirates once they know that he's still alive. And for the record, I think he didn't kill Commander Snack, I think Snack wanted to leave BM pirates and asked Urouge to help fake his/her death.
6. Jewelry Bonney - we don't know where she is yet. But a lot of speculation has been going on that she's affiliated with Big Mom. Probably one of her daughters.
Now we see that all of the SN, except for Bonney, has a strong reason to fight the Big Mom pirates or the Beast pirates. Making the possibility of all of them forming an alliance more likely when both Big Mom and the Beast Pirates are in the picture.
But, why would they need such a strong and a large quantity of alliance? Here's why. You remember the summit war? What the marines needed to pull off just to defeat ONE YONKOU? They had one fleet admiral, three admirals, one vice admiral that's as strong as the fleet admiral, five warlords, all of their vice admirals and pacifistas, 60 warships, and 100,000 soldiers. Not to mention that they had the base advantage so all of their huge cannons are there.
Now imagine the Straw Hat-Law-Mink-Samurai-Colosseum alliance going against the Whitebeard pirates from the summit war. Do you really think they'd win?
We've already seen first hand from Whitebeard how powerful a Yonkou is. With him being old, in bad health, and getting stabbed in the heart, he still stood his ground against the Admirals and almost sunk Marine HQ. Why would it be different for Big Mom, Kaido, and Shanks? I mean, if Luffy and Law fought with a version of Whitebeard right now do you think they stand a chance? They're not even at par with the sweet commanders (Nami & the homies helped Luffy beat Cracker remember?) and the three calamities. That's why there's a strong probability of Oda forming an alliance between the SN for them to have a fighting chance.
And keep this in mind, not even one of the SN joined Shanks or Blackbeard. And currently, not one of them have a reason to go after Shanks or Blackbeard (except Bonney who hates Blackbeard).
With that being explained, let's get to why Big Mom and Kaido will also clash.
Now, why do you think the story is always linked to either Big Mom and Kaido so far? It's the New World, they could've clashed with the other Emperors, but only these two were displayed.
Think of how the story is going so far. Right now the Straw Hats and Tank Pirates are in Whole Cake island and provoked Big Mom like no one ever did. Luffy waged a war against her on Fishman island, ate her sweets, went in her territory, broke mother caramel's photo, ruined the Germa's massacre, destroyed the wedding cake, stole Jimbei, faked Brooke's death, and, well, you get the picture. They made her insanely furious. That's upfront spitting on Big Mom's face. Total disrespect. You can't have that if you're a Yonkou.
Hence, after Luffy & co successfully escapes, I believe Big Mom will follow them to Wano. Though not just because of the reasons I gave above. I think even an impulsive Big Mom won't risk a war against a Yonkou for being mad. So what will be the key? The tipping point for Big Mom and her underlings to follow Luffy & Bege and risk to trigger a war against Kaido?
The answer: The copies of the Road Poneglyph
Now that they have Brulee, Big Mom will be informed about the copies. And then, they'll be no stopping her on going after the Straw Hats, even if they reach Kaido's territory, Wano, and possibly wage a war, which I think will happen.
Thus my theory of Oda's plan to create a war against the three faction.
Big Mom Pirates vs The Beast Pirates vs The Worst Generation Alliance