One of the great tragedies of the Wano Kuni arc is good the discovery of Kanjuro’s betrayal, who actually worked for the other Kurozumi – Shogun Orochi. A twist that was nothing new, Oda having accustomed us over the years to give a hidden past to many characters, foremost among them the members of Mugiwara. Robin was thus seen to abandon the Straw Hats when his past as Ohara resurfaced with the CP-9, which Sanji also did later when the Vinsmoke-Big Mom alliance came looking for him by the collar. A scenario that could happen again?
Indeed, we have seen, like X-Drake, that the World Government had spies on the crews of the greatest captains. We do not see why there should not be among the Mugiwara. In this hypothesis, we imagine that the world government would have approached one of the members during the ellipse, and would have threatened the crew if he did not agree to be a spy.. The member in question would thus always be loyal to the crew – logical in view of their very strong ties – and would seek to safeguard them.
In this context, we imagine that it should be one of the weakest members, therefore one of the most easily influenced. Usopp would be perfect for the role, knowing that he is one of the few whose background is not yet fully revealed – the meeting with his father Yassop has not yet taken place. The most fearful of liars would thus reveal his duplicity when he met Shanks, in one of those immense bouts of tears followed by a moment of mad courage peculiar to Usopp, a tearful fit during which he would save his crew from agents of the World Government. To definitely become God Usopp?