Mary Geoise is actually referencing the Vatikan and Imu is the Pope/Head Priest of this patriarchic structure in One Piece. What does Cavendish has to do with it?
With the solidification of the Holy Knights as a subordinate group to Imu, my theory about the structure inside of Mary Geoise is finally finished. Since a while I have been speculating that Imu is some kind of Pope/Head Priest, the highest authority in the catholic patriarchic structure. As that, it feels like the Gorosei are taking on the role of the High Priests of the Holy Land Mary Geoise.
Knights are royal guards and it is clear that the Holy Knights are referencing the "Templar Knights" of our real life world, who went on a holy crusade to spread christianity throgh europe, up until the middle south east. It is fascinating how Oda is mashing together different christian structures, all being reflected within Mary Geoise and the World Government.
I also think the Holy Knights may only really go into action once a Gorosei gets dispositioned to fight. Priests in medieval era's fulfilled the role of blessing the knights, that were going into a crusade. That's for priests who were sent out to the battlefield. They not only brought the spiritual blessings of god with them, but also medicinical knowledge and sometimes even supportive skills like cooking or other craftmenship.
But most importantly, priests were also capable of excorcising people that fell mentally ill and became "possessed".
Why is Cavendish important for theory? Hakuba is clearly a second persona within Cavendish, we don't know the exact cause of it, but on the one hand it is a blessing of a power, on the other hand a curse to his sanity. But why did Oda even go this far, to create such a unique character in One Piece and give him such massive screentime? Every other commander of the grandfleet has been more significant recently, than Cavendish.
It is because Oda created Cavendish to demonstrate a new concept of splitt personality and possession to us raders/viewers. And to be direct: This will be taking fruits right now!
As many things from Dressrosa foreshadowed the Reverie events, as build up, as herrings, as puzzle pieces - This makes us have a possibly different view on Cavendish from now on.
I believe that the former queen of Alabasta from the Void Century, Nefertari Lili, suffered from the very same possession as Cavendish did!
I want to demonstrate the proof with this. Lili was clearly venturing out, unbeknownst to anyone, but for reasons unknown to us, she sent a letter to the kingdom of Alabasta, which then has been passed down from generation to generation, like a will. Cobra inquisitioning the Gorosei means he is alerted about something. So I think that the past Lili has been warning the future generations about what is to be called "Imu" and that Imu might take over her body and soul for eternity, bringing the world into dusk.
Lili knew she was sick and maybe there was nothing that was able to cure her and she couldn't take it anymore. As a result she neither was able to join the the 20 kingdoms in unity, nor she was able to return to Alabasta. She had to settle down and maybe life off her life to her destined "end".
This might be a rough plug and unoriginal, but she indeed could have found Amazon Lily during that time.
At this point I can imagine that holy figures, priests of the ancient times tried to excorcise her, but they failed. Maybe Lili's other half won the clutch, the dark side took over the light from Lili and Lili vanished for ever into nothingness. Something that theoretically could have happened to Cavendish if noone would "wake him up".
Imu is Lili's Hakuba and the darkness that took over her. Imu thus might not even be a human and this could explain alot. For example, why Imu lives for centuries, and why, the Will of D got corrupted to be splitt into a darkness and light equality.
I hope you guys have read my theory on Imu being Lili's Hakuba and the structure on the World Government.
This is a rough line of theories, but I am convinced that this is one of the most legitimate routes right now.
Have a nice day guys, love ya all! <3