We already know like the Straw Hats the location of three of the Road Ponelyphs, the first being on Zou, the second on WCI and the third being somewhere in Wano (most likely in Kaido's palace at Onigashima) but the fourth's one is unknown. What or who in your opinion could reveal to the Straw Hats the location of that last Road Poneglyph ? What place already known or already spoken of could be it location ? Which individuals are likely aware of its location ? I am sure that Shanks and his closest crewmates in the Red Hair Pirates are aware of its location, I wouldn't be surprised if WB was aware of its location even if he didn't want to collect it, same for the highest levels of the WG. I also find it possible that Oden knew where it is.