I believe this as well.
I believe Imu is fueled directly by Souls. Luffy was shown gaining power because of the Wills of Wano, their Souls urging him to defeat Kaido. If Imu is a twisted version of Luffy, who wants to dominate everything rather than liberate, live as a "Demon", Imu would eat Souls rather than free them.
This explains everything: the slavery, the Human Hunts, even the Jayans committing Ritual Sacrifice to appease a Serpent they worshipped as God. It isn't just about control, Imu needs SOULS.
I think they are somehow fused with the Sunlight Tree, Eve, and that's another reason Roger/Kaido and others couldn't just storm the castle and kill Imu.
If Imu's Soul is residing in the Sunlight Tree Eve, you either need some weird tech to get them out, or... burn the tree. And, doing that would likely have huge effects on the world, if Eve is actually a holy tree.
Since Skypiea has a TON of references to current events, I could see the trees in Jaya that had their ancestors Souls, being foreshadowing to Imu's Soul residing in the Sunlight Tree Eve.
If the Sunlight Tree Eve DOES create the Devil Fruits, then Imu's Soul being in the Tree explains why Devil Fruits users can't swim; it's Imu fucking with the Fruits via the Tree that produced them. This is also why we haven't seen any new Devil Fruits: Imu controls the tree.
Imu's Soul is in the Sunlight Tree Eve.
I'm wondering if, EOS, Imu will dump a lot of Soul energy into the Tree to make new Devil Fruits for Imu's army for the Final War.