Yo,
@Salah WG, is the Uta+Dream Demon combo a mirror to Imu+Whirpool Guy?
No, i think it's more of a Foreshadowing of Blackbeard's True Form
Brook said that His Body & Skills/Abilities are Powered by his Special Soul
Think about it, even though Brook is just a Skeleton, He is able to Function exactly like his Old Living Body
Meaning his Soul was able to carry on all his Functionalities, making Current Brook seem like an Incarnation of his Former Self
The same with Blackbeard, his Body Structure changed because of a Special Soul/Presence inside him
Meaning whatever is inside him belonged to a Being who doesn't Sleep, can Eat multiple DFs, Physically Enhanced ... etc
This is why Luffy/Zoro addressed him as "They", this is why Shiryu sensed something Special about him, this is why Shanks wanna stop him at all costs, it's because of what He could become
So just like Soul of Human Brook got transferred to Skeleton Brook without losing Functionalities of Original Body
Soul of a Very Powerful Being got transferred to Body of Blackbeard granting him same Functionalities of that Being's Original Body
There is One Being who is considered Trion, associated with "Dreams", doesn't Sleep, explains BB's Flag (Three Skulls & Eight Bones), looks similar to BB with Current Beard, considered Sea Devil (That's Epithet of Real Life Blackbeard) ... etc
It's none other than Cthulhu.
Where is Original Body? It's in none other than Enies Lobby, that Dark Pit
That's why Ennies Lobby is Island that never goes Dark, it has a Perma Sun, which probably prevents Sea Devil from coming out
Whirlpool Man is heavily related ofc, but i'm not sure how Oda gonna write his Scenarios, i just suggest Key Points.
Anyway, i believe OP's Biggest Plot Twist is that it's basically a Dream World created by Haki in the vision of it's Creator
But currently Blackbeard is playing the role of the Dreamer, it's like They are living in his Timeline & Luffy must replace him
It's a complicated Story but it will start to make sense once some Characters get Introduced
