In the latest chapter Shinobu is shown to have been spying on the encounter between Oden and Orochi.
So the only one knowing the truth about the conversation between Oden and Orochi (and probably later between Orochi and Kaido as well) is young Shinobu. Her spying scene was exactly done like the one she did with Nami!
Interestingly enough it seems like she didn’t tell anyone about it, at least at first. I wonder if Oden knew she was spying on them and if he did tell her not say a single word to anyone. This still leaves the question about what exactly Orochi and Kaido threaten Wano with, to make Oden dance naked on the street of the Flower Capital for five years, causing most of the people of Wano to lose faith and respect for him.
Shinobu knew the truth of whatever conversation occurred between Oden and Orochi the whole time. Does this make it more likely she’s the traitor now? And will we find out why she never said anything?