While the Koa Pirates stayed for six months in Water 7, the Marines—seeking to boost their popularity and morale against pirates, and possibly increase recruitment—began planning a large-scale battle. Their target: the pirates who had not yet crossed the Red Line into the New World. In "Paradise," the first half of the Grand Line, the Marines had more control, as Marineford was nearby, unlike the chaotic New World.
Among the pirates they aimed to target was the Koa Pirates. Koa, being a former member of the Roger Pirates, made for a symbolic target. Capturing him would send a powerful message to the world: the Marines could still take down even the mightiest of pirates. Such a feat would rally the public and reassure civilians, while intimidating would-be pirates.
The plan was to wait until the Koa Pirates left Water 7 in order to avoid civilian casualties. The operation was to be led by none other than the Marine Hero himself—Monkey D. Garp. A fitting figure to go after Koa, given their shared past with one of the strongest Pirates, and Garp's lingering obsession with Gol D. Roger. Alongside him were the newest Marine graduates: Sakazuki and Borsalino. The mission served both as a trial-by-fire for the rookies and a publicity boost for the Marine ranks.
Once word reached them that the Koa Pirates had finally departed from Water 7, the Marine fleet sprang into action.
"HAHAHAHAHAHA! Those brats won't know what hit them!" Garp laughed boisterously, stepping aboard the warship, his trusted adjutant Bogard by his side, with Sakazuki and Borsalino following closely behind.
"Get ready, you two," Garp said to the rookies. "They may look like a newly formed crew, but their captain is extremely capable. Don't let his low bounty fool you. I've also heard that they've got two Logia Devil Fruit users among them."
That statement prompted a strong reaction. Sakazuki's expression grew intense, clearly itching to wipe out every member of the Koa Pirates, while Borsalino maintained his usual lazy demeanor. Bogard, however, frowned.
"Garp-san, they have three Logia Devil Fruit users," Bogard corrected. "It was noted in the latest report from Water 7. Didn't you read the intel Admiral Sengoku sent?"
"HAHAHAHA! My bad!" Garp laughed again, clearly unfazed by his oversight. He was confident—overconfident—that he alone could defeat the Koa Pirates. He only brought the recruits because he was told to.
Bogard, used to Garp's careless behavior, wasn't particularly surprised. But Sakazuki and Borsalino's admiration for the Marine Hero began to waver. They'd heard of Garp's recklessness before, but witnessing it firsthand left them uneasy.
"Are we going to be okay, Sakazuki?" Borsalino asked, his voice as laid-back as ever. Sakazuki glanced at him, his expression stern with disappointment. He knew how powerful Borsalino was—between his Devil Fruit and natural ability, he could easily surpass Sakazuki, if he ever took things seriously.
"Don't act lazy on the battlefield. That's how you get killed," Sakazuki warned bluntly.
Borsalino smirked, teasing, "Oh? Since when did you start caring, Sakazuki? That's kinda soft of you."
Sakazuki didn't respond. He just walked faster, brushing off the provocation.
A few minutes later, they arrived at the port where the warship was docked. Rows of Marines stood in formation, saluting as the senior officers passed.
"LET'S GO CATCH SOME SCUM!" Garp roared, raising a fist in the air.
"SIR, YES SIR!" the Marines responded in unison, the warship now alive with purpose as the sails were prepared to pursue the Koa Pirates.
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Meanwhile, Koa and his crew sailed quietly across the open sea, following their daily routines without issue. The ocean was calm. The skies were clear. Everything felt... normal.
And then suddenly, Koa's instincts flared.
His body tensed as a wave of dread washed over him. He looked around sharply, scanning the horizon. Nothing. No ships. No birds. No signs of danger.
But his gut told him otherwise.
"Kuzan, Greenbull—get ready. Everyone, start transforming the ship into Submarine Mode. I've got a bad feeling," Koa ordered, his voice calm but urgent.
The crew snapped into action. Submarine Mode was a complex process—it would take over an hour to complete. Still, they trusted Koa's instincts without question.
As the ship began its transformation, Koa focused, reaching out with his Observation Haki.
He felt it.
A monstrous presence—no, more than one. Four strong ones... and one that burned brighter than all the rest. Compared to the others, it was like the sun beside orbiting planets. A titan among giants.
Then, they became visible on the horizon.
And Koa instantly understood who the "sun" was.
Monkey D. Garp.
And orbiting him—Bogard, Sakazuki, and Borsalino.
"Oi, pirate scum! Surrender or die!" Garp's booming voice echoed across the sea as he stood atop the Marine warship, grinning like a man possessed.
Koa smirked. "If it isn't Marine Dog Garp. Shouldn't you be licking the Celestial Dragons' boots like a good lapdog? Don't want to lose your treats now, do you?"
The words instantly triggered Garp, his grin fading into a deep scowl. "You've got a nasty mouth, brat."
"Hahahaha! What? Hit a nerve? Angry at the truth?"
Koa then reached behind his back and took hold of his twin axes, his body starting to radiate with power. He glanced at Kuzan and Greenbull, giving them a silent nod. The message was clear: Prepare for battle.
With a thunderous leap, Garp jumped from the Marine ship, his right fist coated in a blinding combination of Armament Haki and Conqueror's Haki.
Koa responded in kind, infusing his axes not only with Armament and Conqueror's Haki but also with the seismic energy from his Quake-Quake Fruit, channeling sheer devastation into every strike.
As the two titans soared toward one another, Sakazuki tried to flank and strike the Koa Pirates' ship—but Kuzan intercepted him, freezing his magma with a wave of ice.
In the sky, Koa and Garp met.
Each grinning.
Each is ready to kill.
"GALAXY IMPACT!!" Garp roared, swinging his fist like a meteor.
"DIVINE RETRIBUTION!!!" Koa countered, hurling both axes forward with seismic might.
Their blows collided—and the sky split in two.
A deafening shockwave followed. The clouds parted. The sea heaved like a living beast. The explosion that followed was akin to a nuclear blast, shaking the heavens.
On the Marine ship, jaws dropped. The crew watched in stunned silence. Even Bogard's eyes nearly popped from their sockets. Never had he seen anyone—anyone—match Garp in raw power like this.
Not since Roger, Whitebeard, Sengoku, or Rocks.
On the Koa Pirates' ship, the reactions were just as stunned. Greenbull stood slack-jawed. Jhin was frozen mid-motion. Urf stared in awe.
But Enel?
He was smiling.
His eyes gleamed with reverence. This—this was what a god was supposed to look like.
I followed the right man, Enel thought. With newfound conviction, he summoned a raging thunderstorm over the Marines, refusing to let Garp and Koa do all the fighting alone.
Within moments, the once-calm sea turned into a swirling battleground. Lightning cracked. Waves crashed. Ice met magma. And at the center of it all stood Garp and Koa, having returned to their ships, each staring at the other like old rivals reborn.
"HAHAHAHAHA!! Not bad!" Garp roared across the sea.
"That wasn't even close to my full strength, you old mutt!" Koa shouted back, though they both knew the truth.
"That was my warm-up! I'm just showing mercy to the youngsters! HAH!!" Garp laughed, knowing he had given everything in that blow.
They grinned again. Not just as enemies.
But as warriors.
And then, at the same moment—
"ATTACK!!!" they both bellowed.
What followed would be remembered for generations.
The Battle of Water 7 had begun.