Answer (1 of 2): A clash between yonkou would make headlines all over the world, even in a isolated country like wano. If it's the weakened big mom we have right now kaidou should be able to defeat her a lot easier then if she was at full power obviously, and wano wouldn't be in shambles by time
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Now that Law and Kidd defeated Big Mom, are they Yonko level now? - Quora
Now that Law and Kidd defeated Big Mom, are they Yonko level now? - Quora