Fishman Island, Red Line
"Heh… so you think you can escape?" Elder Mars' voice echoed like a cursed wind across the shattered palace. In his Itsumade form—an enormous mythical bird with tattered wings, skeletal talons, and burning crimson eyes—he soared above Fishman Island like a herald of death.
"I'm afraid," he continued, the words dripping malice, "I cannot allow that."
The monstrous bird angled its wings, feathers shimmering with a sickly, ethereal glow. His Observation Haki spread through the area like a sweeping net—piercing stone, soil, and coral with ease. The secret evacuation tunnels were invisible to ordinary sight.
But to Elder Mars? They were as clear as ink on parchment.
He felt the scurrying movements beneath the earth—the desperate rush of soldiers, ministers, civilians. He felt the royal family deeper inside: Otohime's trembling heart, Shirahoshi's weak infant pulse, and the quiet resolve of the sons. And then he found the targets he sought.
"The Queen… and the newborn princess… Poseidon cannot be allowed to awaken."
His wings spread wide, blotting out what remained of the light. Energy surged through his beak, building, condensing—until the air crackled and screamed around him.
Then— FWOOOOOM!
A colossal beam of pure destruction roared downward. It tore through coral and stone like wet paper. The ground split open. Secret passages collapsed instantly. Dozens of fleeing fishmen never even had time to scream—the falling rubble crushed them outright. The blast carved a trench straight through the earth, vaporizing everything in its path.
Elder Mars banked in the air, turning for another strike, his beak glowing again.
"Die quietly, heirs of Poseidon—"
He didn't finish the sentence. Because his Haki screamed. He spun just in time—
CRAAAAASH!!!
A massive blue-and-green phoenix slammed into his side, talons first. Fire and shockwaves exploded across the sky as the two mythical beasts spiraled through the air, their collision shaking the entire island.
The blast from Mars' second shot veered off, instead tearing through the palace ruins further away—obliterating a massive section of what remained of the royal castle. Below, the ground trembled. Debris rained like a deadly storm.
BOOOM!
A fist of pure diamond punched through the collapsed earth. Jozu erupted upward, glistening with dust and jagged shards of coral. Behind him, more Whitebeard pirates climbed out of the ruined tunnel—bruised, coughing, but alive. They had reacted the instant the tunnel began collapsing, their instincts and experience saving who they could.
But even their strength couldn't save everyone. The bodies buried beneath… would never rise again. Jozu grimaced as he checked the survivors.
"Damn it… We weren't fast enough; the tunnels have collapsed. We need to move above ground."
But relief washed over him when he spotted the royal family emerging from deeper inside the protected section of the passage. Queen Otohime clutched Shirahoshi close, trembling—but unharmed.
Thank God.
Above, the air burned. Marco, in his phoenix form, hovered between Elder Mars and the survivors below—his wings spread wide, blazing with blue-green fire. Each wingbeat cast healing embers over the people beneath, shielding them from falling debris. Elder Mars reoriented himself in midair, tattered wings snapping with explosive force.
"The First Division Commander of the Whitebeard Pirates…" He sneered, his distorted beak stretching into a cruel grin. "Boy, just because your bounty barely scrapes past a billion… you think you can challenge me?"
His wings slammed downward. A hurricane blast surged forth. The half-destroyed Fishman Island buckled as hurricane-force winds flattened coral pillars, uprooted buildings, and sent debris hurtling like bullets. Marco didn't move. His luminous flames flared brighter, cutting the winds around Jozu and the survivors, forming a protective barrier.
"Jozu!" Marco roared. "Get them to safety! I'll hold him off!"
Jozu nodded without hesitation, rallying the others and ushering the royal family away from the battlefield. Marco's blazing wings beat once, propelling him forward like a streak of blue lightning.
He slammed into Elder Mars with a fiery dive—but Mars barely budged. The elder's laughter echoed through the sky. "Cute. Truly cute."
Marco hissed, circling back, talons crackling with regenerative flames.
"Puny insect… you surely have a death wish, don't you?"
Elder Mars' voice reverberated like the groan of a dying world. The Itsumade's beak opened wide—too wide, grotesquely wide—as spiraling red-and-black energy gathered in its throat. The air warped around him, space distorting as if resisting the power about to be unleashed.
"And as your elder…" His wings spread, casting a shadow over hundreds of meters of the ruined Fishman Island. "…let me grant you your wish."
FWOOOOOOOM!!!
A colossal beam of corrupt energy tore from his beak. Marco didn't hesitate. His phoenix form ignited fully—blue and green flames erupting skyward as the phoenix screeched in defiance. The heat distorted the air, cracking sections of the superstructures around them. Marco opened his beak and unleashed everything he had.
BOOOOOOOOOM!!!
A massive torrent of phoenix fire blasted upward, meeting Elder Mars' beam head-on.
The two attacks collided in the sky—and the world shattered. The point of impact twisted into a sphere of crackling, howling light. Titan-like forces clashed in a storm of swirling energy. Shockwaves rippled outward in expanding rings, each one strong enough to split coral towers and rip buildings clean off their foundations.
Fishman Island shook like a dying drum. Stone shattered, windows exploded. Tidal currents reversed and spiraled violently.
The shockwave hit the ground— KRAAAAAA-KOOOOOM!!!
A hurricane of pressure tore through the remains of the palace district, sending entire structures tumbling, pulverizing debris into dust, and ripping through coral walls like cardboard. Civilians far from the battle were knocked off their feet, thrown across the ground. Even the protected areas shuddered under the weight of the clash.
But high above, the beams continued to grind against one another, each pushing back, each roaring like dueling stars. Marco strained—he was giving everything, calling on every inch of his phoenix flame.
But Elder Mars did not move. Did not even consider the first division commander. Did not even blink. His ancient eyes watched Marco coldly, almost bored.
And then— Marco's beam cracked. His flames sputtered. And Elder Mars' attack swallowed it whole.
"NNNGGHHH—!!"
The corrupted energy consumed Marco's flames and slammed into him like a divine hammer. His phoenix form was instantly overwhelmed, engulfed in raw destructive force.
He fell. No—he was hurled from the sky.
A streak of burning blue plummeting downward—KRAAAAAAASH!!!
Marco smashed into the ground like a meteor, the impact carving a massive crater across the coral floor. A shockwave burst upward, sending clouds of dust and shattered stone flying. For several seconds, all was silent except for falling rubble.
Then—FWOOM.
A spark of blue fire flickered in the crater. Then another. Then a torrent. Marco pushed himself up, staggering, feathers burned, body torn with gashes deep enough to expose bone. Wounds covered him from wingtip to talon. But they healed.
Slowly because of the haki infused into the elder's attack. Painfully. But unmistakably. His regeneration was in overdrive—flames crawling over his body like desperate hands stitching flesh back together. His breathing was ragged, but he stood. Elder Mars watched from above, unimpressed.
"Ho?" he snorted. "Not dead? Hmph." He descended lazily, his massive wings sending ripples through the air. "Your flames truly are… annoying," Mars mused, voice coated with condescension.
He tilted his skeletal head. "Regeneration is troublesome…" A talon flexed, dripping with obsidian-black Haki. "…but that's all it is."
And then he vanished. Not blurred. Not moved quickly. Vanished. Marco's eyes widened. His observation Haki flared—too late.
WHOOOOOM!!!
A massive talon coated in pitch-black Armament and wreathed in snapping tendrils of Conqueror's Haki slammed down on Marco's chest. The ground erupted. The already massive crater deepened and widened as though a meteor had struck again. Coral fractured in spiderweb patterns for hundreds of meters. Chunks of earth the size of houses burst upward, raining down like meteors.
Marco was crushed into the earth, the shockwave pulverizing the ground beneath him. His flames flickered—his Zoan state was forcibly shattered. The phoenix disappeared, leaving Marco in human form, blood dripping from his mouth.
Before he could breathe—before he could orient himself—before he could even try to transform—Elder Mars' beak glowed inches from his face. A point-blank beam. Pinned down with no escape. Marco's eyes widened—
FWOOOOOOOOOM!!!!
The beam tore into the crater, engulfing everything, the explosion lighting up the entire district like a miniature sun.
WHAM!!!
The island shook. The shockwave blasted upward, tearing apart more structures, sending coral pillars collapsing like dominoes. Dust and fire filled the sky. Elder Mars didn't even look down.
He knew Marco survived—he could sense the stubborn flicker of phoenix flame still faintly glowing in the depths of the crater.
The elder turned his gaze toward the fleeing royal family, toward the survivors Jozu was protecting. His wings raised.
"Oh well," he muttered with cold finality. "Annoying pest or not… your end is only a matter of time."
Elder Mars unfurled his wings, preparing to launch himself skyward in pursuit of the fleeing royal family. His massive shadow stretched over the battlefield as the Itsumade inhaled deeply—preparing another devastating beam that would punch straight through coral, steel, and flesh alike.
But he never fired it. Because a trident, coated in a suffocating layer of pitch-black Armament Haki, pierced through the smoke and dust like a divine spear and— SLAMMED into the Elder's flank with the force of a falling continent.
BOOOOOOOOM!!
The impact lifted the colossal mythical bird clean off the ground—like a ragdoll—and sent him crashing through pillars of collapsed coral and ancient stone. The earth shook violently as the Elder skidded and tumbled across the battlefield, carving trenches several meters deep.
Even for an immortal—even for an awakened Mythical Zoan—that blow hurt. His monstrous head whipped toward the source, and for the first time since arrival… Elder Mars looked shocked.
For standing there, wreathed in a brutal aura of killing intent, was no longer the gentle, diplomatic King Neptune known throughout the seas. This was a warrior, an ancient sea titan reborn.
His eyes glowed red—feral, bloodshot, shaking with fury barely held together. His muscles bulged unnaturally, cords of flesh twisting like coiled serpents beneath the skin. Veins pulsed violently across his neck and arms, each beat pumping raw power through his body.
The calm, affable ruler of Fishman Island was gone. In his place stood the Berserker King of the Deep. Neptune twirled his massive trident once—an action that cracked the ground beneath him—then leveled its obsidian-coated prongs at Elder Mars. His voice was a guttural growl.
"Stay… away… from my FAMILY."
The battlefield stilled. Even Elder Mars narrowed his eyes, feathers bristling. He felt that blow. He felt the weight of this change. This wasn't ordinary strength. This wasn't Haki mastery. This was a symptom of something forbidden.
Behind Neptune, Marco clawed his way up from the crater, blue flames flickering weakly around him. He stared at Neptune in disbelief. That aura—that unnatural swelling of muscle—that explosive pulse of strength—Marco, as a doctor, had seen men driven berserk by stimulants, Zoans driven into madness by chemicals… But nothing like this.
Neptune reached into the coral pouch at his waist with trembling fingers and pulled out what looked like a handful of shining capsules—each one glowing faintly like pearls forged from lightning. Marco's eyes widened.
"Wait—King Neptune, are those—?!"
Neptune didn't answer. He stuffed the entire handful into his mouth and crushed them between his teeth.
CRACK.
His body convulsed. His muscles doubled—then tripled—in size, skin tightening over monstrous new bulk. A shockwave of raw physical energy erupted from him, blowing chunks of debris away and forcing Marco to shield himself with his wings.
Neptune roared—a sound so deep the coral itself vibrated, echoing like a beast long imprisoned.
Marco staggered. He understood now. The "Deep King's Ambrosia," or simply known to the world as "energy steroids," a forbidden sacred drug. A national treasure of the fishmen race—seal-bound and buried, meant only for the final hour of their extinction.
A drug potent enough to turn a fishman or merfolk into a monster of the abyss. A drug lethal enough to kill its user afterward. Marco felt a chill. Neptune knew the price. He didn't care.
Neptune's body had swelled monstrously. A king already huge now stood like a titan—the size of a palace tower, shoulders like mountains, trident crackling with Haki so dense it split the air. The veins across his arms bulged like hoses pumping fire. His breath came out as steam. His eyes burned crimson. Yet his voice, when he spoke to Marco, was steady—soft beneath the rage.
"…Marco."
Marco struggled to stand straighter, forcing his phoenix form to stabilize.
"Y-Yeah… King Neptune?"
Neptune didn't look back at him. His gaze was locked on Elder Mars like a predator fixed on prey.
"I will confront him head-on." The titan's grip on his trident tightened, the metal groaning under the pressure. "Can you support me… from the skies?"
Marco froze. Protest filled his throat—he wanted to shout, "This will kill you." He wanted to scream, "There must be another way." He wanted to warn him: That drug will tear your body apart before Mars even gets the chance. But the words died when Marco's gaze drifted across the battlefield.
He saw merfolk torn apart. Children crushed under rubble. Fishman soldiers dying in droves.
The entire island was in ruins. The sea people's sanctuary was burning. This was hell. And the king had made his choice. Marco's jaw tightened. He inhaled sharply—and the phoenix rose once more, wings bursting from his back in a waterfall of azure flame. He ignited the sky.
"Understood." His phoenix eyes glowed fiercely. "I'll cover you. As long as I can still fly—I'll keep him off you."
Neptune's massive frame leaned forward, the ground cracking beneath one titanic footstep.
Elder Mars hissed, feathers rising in agitation, sensing the overwhelming surge of power approaching. The Berserker King bared his teeth.
"Then let us end this, you heartless bastards…" He lunged—a titan charging the heavens. Elder Mars barely had time to steady himself before the titan was already upon him.
BOOOOOOM!!!
Neptune's first step cracked the battlefield. His second tore it open. His third sent shockwaves rippling through the entire palace district. The sheer force of his movements bent the coral beneath him like warped steel. With a roar that carried generations of pain—
"RAAAAAAAAAHHHHH!!"
—Neptune swung his trident. Mars raised a wing instinctively, coated in deadly Haki, but the moment the weapon made contact—
KRAAAAAASH!!—he was sent flying again. The wing bones buckled, the feathers singed, and the immortal elder's body carved trenches through collapsing towers. The shockwave blew Marco back midair, even in phoenix form. Neptune did not chase immediately, as he realized the attack did nothing to the elder. He reached into his coral pouch with trembling fingers… and pulled out three more glowing capsules.
Marco's eyes widened in horror.
"NEPTUNE—!!"
But the king threw back his head and swallowed them all.
CRUNCH. CRUNCH. CRUNCH.
His body convulsed. Veins bulged like serpents. His muscles ripped and reknit instantly, black Haki seeping from his pores like smoke. A pulse of raw killing intent exploded outward, forcing rubble to vibrate, forcing even Marco's wings to falter. The Deep King's Ambrosia was ravaging him. Tearing him apart. But also feeding him strength beyond mortal limits.
Neptune didn't care. He only whispered, voice breaking: "They killed my people…" His pupils dilated. His breath shook with rage. His trident glowed pitch black with Haki. "…they slaughtered my race..." His hand tightened so hard the metal shaft bent under his grip.
"AND YOU THINK I WILL DIE QUIETLY?!"
The Itsumade erupted from the rubble, wings spread wide, screeching with fury. His beak began to glow, gathering energy for another beam.
"YOU LOWBORN FISH—"
But he didn't finish the sentence. Because Neptune was already there. The massive fishman vanished—no, he moved so fast the ground split behind him. His trident pierced the Elder's chest.
SHUNK!!!
Blood sprayed in an arc across the shattered battlefield. Elder Mars' eyes bulged in shock.
Immortal or not, pain was pain.
"W-What—?! Impossible—!!"
Neptune didn't give him time to recover. He grabbed the elder's beak with one massive hand, clamping it shut so the beam couldn't fire.
"YOU THINK THIS IS IMPOSSIBLE?" Neptune roared, voice cracking with grief and rage. "COME TO FISHMAN ISLAND! WATCH THEM BURN MY PEOPLE! FEEL THEIR BONES BREAK UNDER YOUR FEET!"
He lifted the elder by the face— and SLAMMED him into the ground.
BOOOOOOOM!!!
The impact crater widened hundreds of meters. Marco swooped in from above, unleashing a barrage of phoenix fire to keep Elder Mars pinned.
"NEPTUNE! DON'T OVERDO IT! THOSE PILLS—THEY'LL KILL YOU—!!"
Neptune didn't even look at him. He reached into the pouch again. More pills. More forbidden ambrosia. The last of his island's ancient treasures. He swallowed four at once. Marco screamed, but it was too late.
CRACK–POOM!!!
Neptune's blood boiled through his skin. His muscles tore and reformed constantly, like waves crashing over stone. His size increased again—now towering like a colossus, a titan of old sea myths come alive. The ground beneath him cratered simply from his presence. His red eyes burned with madness.
"I WILL NOT LET MY RACE BE PURGED LIKE ANIMALS!!"
He swung again.
BAM! BAM! BAM!
Each strike of his trident smashed Elder Mars deeper into the ground. Each blow echoed like thunder rolling through the sea. Each impact shattered coral and cracked ancient structures. Elder Mars desperately unleashed Haki-coated wing slashes, but Neptune caught the wing mid-strike and snapped it like rotten driftwood.
CRRRRRACK!!!
The Elder screamed. Neptune lunged, slamming his shoulder into the Elder's ribs, sending him skidding through stone walls like a projectile.
"THIS IS FOR MY SOLDIERS!" Another strike.
"THIS IS FOR MY PEOPLE!" Another.
"THIS IS FOR MY CHILDREN!" He drove the trident down.
"AND THIS—THIS IS FOR MY WIFE!" The trident pierced the Elder's back, pinning him down like a butterfly on a spear. Blood sprayed. Haki cracked the air. The earth groaned beneath the force.
"You… wretched… WRETCHED FILTH!" Mars' body convulsed as he awakened deeper power. His feathers darkened. His talons turned obsidian. Lightning crackled across his beak. He unleashed a shockwave of Haki so powerful it threw Neptune backward, ripping the trident from his grip. The Elder rose, battered but furious, burning with godly wrath.
"You dare defy a god…?! You dare raise your weapon against ME?!" He fired another massive beam.
FWOOOOOOOOM!!!
This one was aimed at Neptune's head—a killing blow. But a wall of blue-green flame slammed into it. Marco. Wings spread, feathers burning away, struggling, screaming as the beam overwhelmed him.
"NEPTUNE—MOVE!!"
The king roared and charged, ignoring Marco's desperate struggle, ignoring the beam, ignoring the pain. He grabbed Elder Mars by the neck. And lifted him into the air. Their faces inches apart.
"IF FISHMAN ISLAND FALLS…" Neptune growled, voice trembling with agony but unbroken resolve, "…THEN I WILL TAKE YOU WITH IT."
He opened his mouth— And swallowed the last of the pills. All of them. Every remaining forbidden capsule. Hundreds of years of national treasure. Swallowed in one suicidal gulp. Marco screamed from above. Mars shrieked in panic. Neptune smiled—the smile of a dying king happy to burn with his enemy.
BOOOOOOOOOM!!!
His aura exploded. His muscles swelled. His skin cracked like stone under volcanic pressure.
Blood turned to steam. Haki poured from him like liquid darkness. He became a monster of sheer, unrestrained power. A sea god reborn through sacrifice. Neptune wrapped his titanic arms around Elder Mars, locking the elder in a crushing grip.
"You're not getting away," he whispered. "Not until I drag you into the abyss with me."
The earth trembled. The sea roared. Marco's flames faltered as he watched in horror.
Neptune's body began to break—spine cracking, muscles tearing—but he held on. The titan's roar shook the heavens.
"DIEEEEEEE!!!!!!!!!!!"
Their combined power detonated—and the battlefield disappeared in white light.