Okay, this is a theory about the destruction of Fishman Island, Big Mom, Caribou, Kaido and how it all connects with each other. We all know that Madam Shyarly made a prediction about Luffy destroying Fishman Island and that, so far, everyone of her prediction have come true so there’s really no real reason to doubt that this prediction won’t come true.
Let’s start this with this theory’s key figure, if you like, Caribou. During the Fishman Island Arc we had Caribou running around all over the place, getting his ass kicked with no real meaning, he’s more or less a filler character during this arc except for stating that overconfident logias will get their ass kicked in the New World; but doesn’t he have any meaning? I believe he had one meaning and that he will play a “bigger” role if you like, in the end.
Here we can see that he learned that the princess Shirahoshi is an ancient weapon, capable of destroying the world; later on, when he had learned about this, he also tried to kidnap the princess but was it for himself that he tried this? Apparently not.
Here we can see that’s he specifically talking about a person that will ” Take A Shine To Him For Sure” if he can bring both of does things to that person. Even though I’m pretty sure that the person he wanted to give these things isn’t the person that will have it in the end, but it wouldn’t surprise me if his plan was to give these things to a Yonko; in the New World you either ally yourself with the Yonko or you fight them, something like that at least. I do believe that Oda will use Caribou, there is no reason to make him eavesdrop, learning such delicate knowledge and then don’t making it affect the story.
During his cover story Caribou fights and defeat Scotch, one of Kaido’s subordinates (or something like that) and later is defeated by X-Drake who is working for Kaido at the moment. Considering that Caribou messed with something of Kaido’s (Scotch and Weapon Factory ) he’s probably going to have to answer to Kaido; at this point he will most likely just spill the beans and tell him about Shirahoshi trying to save his life.
Caribou is also a type of Reindeer so that would work with Kaido’s Animal Theme. Would Kaido care about something like an ancient weapon? Of course he would, Jack is using Ceasar’s poisonous weapons to defeat the Minks and then we have this panel;
Kaido is planning to start a war and, judging by this panel, he doesn’t care if the world is destroyed or not; the ancient weapon of Poseidon have the power to destroy the world.
So, why isn’t Kaido aiming to take Shirahoshi yet? Well there could be several reasons but I’m thinking about two;
– He doesn’t know about it yet
– He does know about it but attacking Fishman Island at this point in time is attacking Big Mom, you don’t believe me?
– Being preoccupied with other things too, like Raizo etc.
From these panels I read it like “Fishman Island is still your territory but I will find you, beat you up and make it my own territory” so, at the moment, Fishman Island ISN’T Luffy’s territory yet; even if Kaido knows that Shirahoshi is there he will probably think twice about clashing with another Yonko and I don’t know a surprise attack is viable considering the power of knowledge the Yonko’s seem to have. Also, Big Mom would be really interested in Kaido’s reason for attacking her -> Maybe finding out about Poseidon.
Will this change? Well, Luffy will go after Sanji soon and he said he would kick Big Mom’s butt; it wouldn’t surprise me if Big Mom is the Yonko to go down first and when she does he will put his flag to mark the island as his territory; which is my last point.
By now Kaido will know about Shirahoshi and he will also know about Doflamingos downfall; and about the person who stopped Doflamingo and thus himself in his tracks, this person is Luffy. Kaido will go after Luffy and he have at least two reasons for attacking Fishman Island;
– Easily getting to Luffy, punishing him.
– Shirahoshi and poseidon will be there
This fight between Luffy and Kaido will be the end of Fishman Island. Luffy is also the person that is responsible for both reasons Kaido does attack Fishman Island;
– Angered Kaido, marked the Island with his flag.
– He brought Caribou to the island and thus the secret about Poseidon leaked.