Well yeah but honestly I care about Nidhogg lore more than Imus. Mainly because I'm curious why War God decided to fight Nika. Sure, I would be happy to know something about Imu but I'd rather know more about characters I actually like.
Considering the very personal way Imu talks about Nidhogg and Nika I'm fairly certain they're all entangled.
Though Imu- their silhouette form at least- is personally entangled with Joyboy.
tinfoil: I'm starting to think that zoans carry haki AND maki of their previous users, which "paint" the hagaromo in awakening of the current user as light or dark. But Imu seems to have fully merged with their devil?? Or something??
Luffy using the maki of Nika would be really interesting
Sun god = nika,,
Forest god = Imu,,
Sea god = Davy,,
Earth god = Nidhog,,
The big question is if these gods as depicted in Harley are referencing the "devils" or the humans who host them or both. I don't think it should be mix-and-match, so Imu shouldn't be there and instead whatever "devil" is of "the devil's fruit" that he has. Or, it's functionally overlapping because this is all in-universe historical mythology:
Sun god = Nika / Joyboy (and now Luffy)
Forest god = ??? devil / Imu
Sea god = ??? devil / Davy
Earth god = Nidhoggr / Elbaf King of the past (and now Loki)
I think the forest and sea gods need a clear successor from the present, and Blackbeard usurping Imu seems the most obvious. But that tangles up Davy's will, unless Davy isn't related to the Sea god at all (I suspect this is the cast, his relation to the bottom of the sea seems to be a prison the same way Imu is imprisoned on top of the Red Line)