First of all, i saw someone comment about this book a few days ago, and quickly read the parts that looked more relevant so i could make this theory in time for this stream, so the theory is a bit rushed and i havent finished the book.

Second, its seems there isnt a way to put images here (or i couldnt learn how), but images are essential for the theory, so i put the number of the pages of the images i reference, i would strongly recommend you pull up a PDF of the book to see the images https://archive.org/details/sacredsymbolsofm00chur_0/page/n9/mode/2up

Third, English is not my first language, i used ai to help me translate a few parts so sorry if its weird...

Maki is stolen haki

I believe maki is created by stealing the haki of a slain adversary. Imu stole Joyboy's haki, Garling stole Xebec's, and Blackbeard will steal Shanks's. The themes and narrative of the story point to all three of these characters being closer in nature to thieves and frauds, rather than kings and gods. For this reason, I think it would make sense if their power is stolen, not earned.

Imu's maki

As stated above, I believe Imu obtained his maki by killing Joyboy and stealing his haki. We know for sure that Joyboy is dead, and that he fought against Imu in the void century. Putting these two together, the natural conclusion would be that Imu dealt the final blow that killed Joyboy.

In Elbaf and Shandora, we've heard about four different gods in the One Piece world with legends that spread across different races. Their name may differ a bit, but I think they're still the same gods and I think one of the gods is Imu.

IMU IS THE FOREST GOD

First of all, Imu has the same rhythm that both Luffy's Nika transformation and Qilingham's Zaza monster had. I believe this will be a common trait of the four gods. Just like how Nika's rubber-like power makes his heartbeat sounds like the Drums of Liberation and Zaza's storm power makes her dance sounds like rain (Dance Powder connection btw), Imu's powers put the devils that he control inside inanimate objects (oddly wooden things) and make them sing.