Gorosei to Shanks when he appeared in Marijoa: "what do you want? Someone with your standing shouldn't be involved in the world affairs. We will only listen to you because it's you"
Is this how you talk to a holy knight who serves as a pawn? So a holy knight basically attacked a WG ship, stole the Nika fruit and is now an emperor.
Well, the "possible" (im talking out there) idea is that Shanks is the 9th Knight that doesnt follow the same role as the rest of them.
The fact that Oda only had 8 countries revolt, yet 9 exist is pretty telling that if he shows them being stopped, then only 8 of 9 can be directly revealed this way (unless ofc someone doubles up).
Again, just a random thought on that