ONE PIECE: MARINEFORD'S GREATEST SCIENTIST
After transmigrating, Natsume finds himself in the body of an eight-year-old child. Shortly after awakening, he activates a technology system, granting him advanced knowledge far beyond the current level of the One Piece world.
Assuming the identity of the younger brother of Kizaru, Natsume joins the Navy’s Technology Department. There, he begins his groundbreaking research, starting with Seraphim, advanced humanoid combat machines. With continuous upgrades, he develops the Admiral-class Seraphim, eventually achieving the pinnacle: Rocks Seraphim, autonomous war machines capable of rivaling even the strongest Yonko commanders.
With these technological marvels, Natsume begins disrupting the balance of power at sea. The Seven Warlords, once pillars of strength, are no match for his creations. The Yonko—considered almost untouchable—face unprecedented threats as well.
Among Natsume’s most ambitious projects is the Cosmic Fruit Tree, an entity surpassing the legendary Devil Fruit Tree. Its fruits grant abilities that combine powers reminiscent of the strongest Devil Fruits, Haki enhancements, and even unique technology-augmented effects, creating a whole new tier of combat potential.
Natsume’s arsenal also includes:
Iron Man Mechs—giant exosuits for frontline combat and heavy artillery
Haki-enhancing Apples—fruits that temporarily boost Haki to extreme levels
Kinetic Energy Drinks—enhancing strength, speed, and stamina
Nuclear Pacifists—weapons designed for deterrence rather than destruction
As a result, the entire pirate world spirals into chaos:
Blackbeard: “You won’t believe it… but two low-tier Seraphim wiped out half my crew!”
Doflamingo: “The age has changed. The new era belongs only to Natsume!”
To counter Natsume’s technology, even the pirates begin to replicate his creations, triggering a technological arms race between the Navy and pirate crews:
Four Emperors: “We spent every last coin trying to keep up!”
Navy Officers: “You think we’re in any better shape?”
Celestial Dragons: “You won’t believe it… but we’re broke too!”
Natsume, ever the schemer, remarks wryly:
“You begged me to develop these things, practically on your knees. Now that everyone’s broke, it’s my fault?”
