When the Big Mom Pirates arrived at Wano Country, we saw many of Big Mom’s children like Smoothie, Perospero, Oven, Daifuku.
The glaring absences here are Cracker and Katakuri, who likely stayed in Whole Cake Island.
This has led many people to speculate that Blackbeard will invade Whole Cake Island, fight (and maybe kill) Katakuri and take what he wants (the Road Poneglyph).
Did Oda already foreshadow Blackbeard Pirates in Whole Cake Island?
Oda already predicted Ace’s death in a colorful cover that no one would suspect. So that would not be ridiculous.
*Theory by Rique47