Mary Geoise’s National Treasure is one of One Piece’s biggest mysteries. While fans don’t know the specifics, it might very well change everything. The National Treasure of Mary Geoise was first introduced by Donquixote Doflamingo during his fight against Trafalgar Law in Chapter 761 of the One Piece manga.
When Law asked Doflamingo how a former Celestial Dragon such as himself was able to mobilize the CP0 and had the World Government on strings, Doflamingo told him that he knew about the existence of the treasure was hidden at Mary Geoise.
I think the secret treasure Doflamingo was pertaining to at Mary Geoise is the ancient weapon Uranus aka the lightning strike that erased Lulusia Kingdom. As Im crosses out Lulusia from a map, a strange flying entity shows up in Lulusia’s skies. It then rains down a massive light blast onto the country, wiping it out nearly instantly.
Unfortunately, for Im, Uranus needs a “key” for it to activate. I believe this key is Vivi. This could explain why it only appeared/was used now. Im currently has Vivi captured and can now freely use Uranus. This would explain why Im had Vivi’s photo, even taking it with him/her to the empty throne. In perfect condition even.
The destroyed photos of Luffy, Teach and Shirahoshi could mean that they are the people Im wants to erase (like Lulusia’s fate) and he/she will use Vivi’s ability to control Uranus hence the presence of her photo.
Vivi is not the light that needs to be erased but is the person who has the power to erase the light. As for the God Valley incident, it could be that it was the previous Ancient Weapon who caused it and has long died. Vivi is the successor of Uranus.
I also believe the power to control Uranus is only passed on to a Nefertari. This could also be why the Nefertari King 800 years ago refused to be a Celestial Dragon. Uranus is hidden at the Holy Land but it is useless without the chosen Nefertari as key.
*Theory by Outrageous_Ad_2658