End of Act 3 with some big revelation about Wano and what he's going to do
His goal has always been the distruction of Wano.
So my little theory is, Orochi actually always suspected that Kaido would someday just betray and kill him so in case that Happened and with the fruit he possesses Orochi will start his plan to erase Wano Country from the map and with that he would start the Wano ticking clock which I am always wondering what will it be and this is a plausible option.
Orochi is probably one of the most prepared villains we have seem he was always suspicious and always had plans for enemies that he didn't even know really existed.
And not only that but somehow Kaido would get to know what Orochi is actually planning then in a desperate try to avoid Wano being destroyed for his own good fly towards the Flower Capital, that's when the supernovas follow him to Wano's main land where his fall will happen and with that not only would Orochi fall Infront of his people but also Kaido and with that Oda's formula would be fulfilled.