I’m rewatching the anime right now, and it’s at the part where Orochi is talking to CP-0.
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At first, I thought that Akainu might not know anything about what they’re talking about, but then I realized something: What if he does?
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I don’t think Akainu will ever admit it to his men, but I think Akainu knows the World Government is buying weapons from Wano. I mean with all of the arsenal and weaponry the Marines have, he’s gotta have some idea of where that comes from.
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So Akainu is scared of attacking Wano because if he does, they’ll no longer have any place to get weaponry from. And it’s just my hunch, but I feel like the World Government isn’t just getting normal weapons from Wano – but weaponry using Seastone.
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So the Marines will never attack Kaido because they NEED him since he, Wano and Orochi are in business with the World Government.
*Theory by Tatlo