Kaido aiding the WG by trying to kill WB as the man was about to go to war with the marines is completely out of character for him. Whereas WB was a former Nakama and a rival of Kaido’s, the WG literally tried to have Kaido enslaved when he was a kid. Not to mention Imu turning Rocks into a demon.
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You're acting like he was openly going to aid the world government and team up with them against Whitebeard. He wasn't motivated by some desire to help them, the Yonko have separate conflicts with eachother, and Kaido decided to take advantage of WB being out in the sea and dominating the news at the time. Them being on the same crew as eachother 30+years ago clearly doesn't matter to any of the Rocks pirates, since they ended up in conflict.
Also, part of the reason it's out of character for Kaido is that Oda likely didn't make up his character by the time of impel down, which was like a decade before Wano. Oda could have tried retconning it, but didn't for whatever reason. Now that Kaido is out of the story, we can assume that he genuinely did want to kill WB, and there isn't going to be a twist
We saw Kaido ally with BM against the WG. Why wouldn’t he have done the same with Whitebeard? Kaido’s dream was a war with the WG.
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Do you not remember how he allied with Big Mom? He threatened to kill her, sent his men to knock her ships down, and fought her for 3 days. Eventually when he got tired of it, he decided they should ally with eachother for the time being,focusing on finding the OP and ancient weapons. But the initial goal of killing her was still a thing.
It honestly makes more sense that Shanks is still somewhat in the pocket of the WG. He stopped Loki, he stopped Kaido, and he was shown snitching to the gorosei in reverie. That couldn’t have been Shamrock as Shamrock is a holy knight and the Gorosei’s comment about him not having a place in politics would make zero sense.
I feel like we've had this argument before, just on opposite sides. The Shamrock thing doesn't really make sense, but that's because it happened at the end of WCI, and Oda didn't want to make it to obvious that it wasn't Shanks. The Gorosei couldn't exactly have acted normal around "Shanks" or else it wouldn't have really made sense. And the comment about "politics" could just be viewed as relevant to the reverie politics, which the CD's wouldn't necessarily care about, since it's mostly the surface world kings discussing stuff.