One Piece has simple themes, it a story for pre-teens after all, that were spelled out by Oda in chapter 100 and Imu serves as the perfect foil to each of theme.
Inherited Will: Imu is a literal immortal who has survived for near a Millenia but will be defeated not by fellow immortal person but by immortal ideals. 800 years ago Imu won the most decisive military victory possible yet his adversaries despite their total defeat manage to get the last laugh as they weren't defeated on the plane of ideology and thus had their dreams carried on by the next generation.
The Dreams of Men: Imu floods the world to constrain adventure. The dangers of the sea are expounded time and time again in East Blue. Vegapunk specifically mentions it in his speech. By undoing the flood the story comes back full circle to the title of chapter one “Romance Dawn”. A New Dawn for adventure and romanticism in the new world created by Luffy.
Flow of the Age: Imu is a dinosaur stuck in the past. He is stuck in the world of 800 years ago and can not move past his Joyboy fetish. One Piece is a story of cycles and eras. And more than anything, it celebrates the malleability of the moment and how the one constant in history is change. Shanks, Garp, Whitebeard, Roger, Luffy, and many more all tout the inevitability and beauty of new eras and how history is ever moving, ever changing with constant rises and falls. And conversely, Imu represents the diametric opposite, stagnation.
Pursuit of Freedom: Despite having the world at his fingertips for 8 centuries, Imu is a prisoner in his own Kingdo, hence why he can’t leave Marijoa. This is stands in stark contrast to Luffy's main ambition to be the freest man on the sea while controlling nothing. Imu controls everything but still enslaved while Luffy controls nothing but is the most free.
In fact the exact Japanese wording Luffy uses in Saobody about not conquering is the exact same as the one Imu uses for Dominion which as this chapter showed is his main theme.
Inherited Will: Imu is a literal immortal who has survived for near a Millenia but will be defeated not by fellow immortal person but by immortal ideals. 800 years ago Imu won the most decisive military victory possible yet his adversaries despite their total defeat manage to get the last laugh as they weren't defeated on the plane of ideology and thus had their dreams carried on by the next generation.
The Dreams of Men: Imu floods the world to constrain adventure. The dangers of the sea are expounded time and time again in East Blue. Vegapunk specifically mentions it in his speech. By undoing the flood the story comes back full circle to the title of chapter one “Romance Dawn”. A New Dawn for adventure and romanticism in the new world created by Luffy.
Flow of the Age: Imu is a dinosaur stuck in the past. He is stuck in the world of 800 years ago and can not move past his Joyboy fetish. One Piece is a story of cycles and eras. And more than anything, it celebrates the malleability of the moment and how the one constant in history is change. Shanks, Garp, Whitebeard, Roger, Luffy, and many more all tout the inevitability and beauty of new eras and how history is ever moving, ever changing with constant rises and falls. And conversely, Imu represents the diametric opposite, stagnation.
In fact the exact Japanese wording Luffy uses in Saobody about not conquering is the exact same as the one Imu uses for Dominion which as this chapter showed is his main theme.
