Setting aside all the mindblowing and awesome things that were revealed during the Reverie Arc, this theory will focus on the Gorosei’s statement about the light that needs to be extinguished.
Oda wants us to believe it’s the Nefertari family, due to the Gorosei talking about them being the traitors, but I don’t think that’s the case. Cobra, the patriarch of Nefertari family, expressed his intentions to ask about the Ancient weapons. I believe that this is the real reason the Gorosei want him and his family gone.
Now, the only two known Ancient Weapons are:
1. Pluton, and any chance of its recreation was destroyed by Franky.
2. Poseidon, whose current host is none other than Shirahoshi.
The Gorosei also talked about how the Nefertari Family fled to the surface eight hundred years ago. They implied that anyone who wants to ‘go to the surface’ is a traitor.
Shirahoshi wants to go to the surface, and we already established that anyone who wants to go to the surface is a traitor according to Gorosei.
The fact they talked about the Nefertari Family at the time is merely a red herring, with plenty of hints dropped in this direction. The ‘light that needs to be extinguished from history‘, the one that the Gorosei want to get rid of……
Shirahoshi is that light.
In this panel, her picture is at the very top, with a sword buried into it, and this panel also implies that Im, the one that the Gorosei asked which light to extinguish, threw in at her picture on purpose.
*Theory by Phos