OK :
Lets say Luffy is redoing Ace life. There is plenty of arguments, like hella arguments, but lets say its directly stated in the manga by Whitebeard that the guy that will inherit Ace will will be the one that finds the One Piece and… beats the WG. So for me: BB → Akainu → Imu.
But its also linked with another thing. Elbaf tree is called Adam tree and is composed of three worlds. But there is also a tree called the Eve tree. Thats the tree that gives sunlight to Fishman Island. Usopp literally says that this tree and the Adam tree are linked, but anyways. There are a lot of things I could say to show even more that both trees are linked, but I think its already enough.
Now, if Elbaf tree has three worlds, why wouldn’t Eve tree have three too?
Eve tree roots are located at Fishman Island, meaning its the “start” of the tree, the first world. Well… Davy Jones, Hody Jones, Vander Decken and his ancestor history that is ODDLY similar to Davy Jones… the fact that Blackbeard powers are dark like deep water but also stop DF powers… like water, the fact that Hody Jones when he is a Kid look like blackbeard when he was also a kid? Oh, and also the fact that Loki, who is linked to Xebec, is in the first world? Anyway: Blackbeard.
Lets also say that the top of the tree is at the Holy Land, because its at the top of the Red Line which is located above Fishman Island. Some of the Sabaody-looking trees (which are considered to be of the same species as the Eve tree) are used as transport areas for people going to the Holy Land during the Levely. So lets say its Imu, because that’s kinda obvious.
So we have 2/3 worlds, one left. Well, the only thing that was ALWAYS in between those two, pre or post ellipse… its Marineford. Thats the only thing that didn’t move (well it does, but you know) and stayed in the middle of both worlds. So Akainu.
There is so much more, but like I said I don’t want to write a whole huge ahh text for One Piece.