So as I've been surfing around the one piece communities to quench my thirst for theories I've come across a lot of theories in which:
==>Luffy is considered to be the son of Im and Dragon
==>Shanks is supposed to be a noble
==>And Shanks is the successor to the empty throne
And here's my theory Im is a female Celestial Dragon who was quite powerful, she was married of to another Celestial Dragon who was older and despicable but happened to be in the role that Im possesses right now. Even though she hated him she still had Shanks with him. Skip to a couple of years later when that dude dies and Shanks leaves home to become a pirate without anyone else noticing and Im stumbles across Dragon iand in the classic stable saves princess style Dragon takes Im away and Im finds true love in Dragon and out comes Luffy.
Meanwhile the WG finds out about Im and force her to leave threatening to kill Dragon and Luffy if she resisted. She leaves but once shes back in her hometown she refuses to stay submissive and proves herself to be stronger than anyone else and retains the throne.
I know this sounds a little far fetched but I can really see this play out, I mean Shanks is the kind of character that prioritizes power balance to maintain peace so he wouldn't back off from inheriting the throne and maybe that's why the Gorosei agreed to meet him.
Like imagine the badassery and the magnitude if this were true and let me know your thoughts and opinions on it..
P.s: this is a theory I came up with after reading several other theories about Im.