Above Beehive Island, Finn floated in the open air and watched the dark space below him shrink.
It had been roughly the size of a colosseum when he'd sealed it. Now it was compressing steadily, the walls of absolute darkness pressing inward, pulling toward something the size of a large building. He could feel the struggle inside it -- two Emperor-level presences pushing against the walls with everything they had, and the walls holding.
Not for much longer.
He was not particularly concerned about that. He had somewhere else to be before they got out.
Finn had been carrying Pluto since Alabasta, and the question of what it was actually capable of had been sitting in the back of his mind since the day he'd acquired it. The Mary Geoise operation had given him one data point which told him something about its ceiling but nothing about what it did to ordinary targets, even extraordinary ordinary targets. He had tested it against islands in private, confirmed that a single shot could erase a mid-sized island without difficulty, and filed that as baseline.
The problem with islands as a measurement was that any of the top combatants could erase a mid-sized island. Sakazuki could do it. Finn could do it himself. The metric said nothing about whether Pluto was qualitatively different or simply operating at the same tier by a different mechanism.
What he had never found, until now, was a target that would give him an honest answer.
Kaido had described himself as immortal, which was probably an exaggeration, but the body underneath the boast was genuine -- the most physically indestructible human frame alive, armored in scales that the weapons of the world had spent a lifetime failing to penetrate. Charlotte Linlin had the Iron Balloon: a defensive architecture built over decades of extreme physical conditioning and Haki development, the thing that had allowed her to keep fighting through punishment that would have ended anyone else.
Two people who were, in different ways, the closest things the world currently had to indestructible.
Very suitable targets for a gun test.
Finn raised his hand. The darkness behind him shifted, pulling back and opening into something else -- a gap in the dark sky, and through the gap, the barrel of Pluto emerging into the air. Ancient, vast, completely out of scale with the surrounding sky, the muzzle orienting downward toward the shrinking dark sphere below.
Dark elements flowed from Finn into the weapon. He could feel the process -- the way Pluto drew from the Dark-Dark Fruit, the particular interface between the ancient weapon's mechanisms and the fruit's power, a compatibility that had always made Pluto respond to him in a way it might not respond to someone else. The charge built. The muzzle began to change. Something accumulated at the barrel's end that didn't have a clean physical description -- a pressure, a gathering breath of destruction that made the air around it look slightly wrong.
Below, the Sakazuki-Newgate battle ground on without pause.
Newgate felt the shift in the atmosphere first. The quality of what was gathering above made him want to look up, the way a change in pressure makes an experienced sailor check the horizon. He pulled his attention from Sakazuki for half a second.
Sakazuki used the half second. He kept moving, kept pushing, magma and momentum together, giving Newgate nothing to work with. He had seen Pluto before. He knew whose hands it was in and where it was pointed. He went back to work.
Newgate read Sakazuki's absence of reaction and concluded that whatever was gathering above was not aimed at this engagement. The mad dog across from him was not protecting himself from it. And the mad dog was still attacking at full output, which meant Newgate didn't have the luxury of looking up to confirm.
They kept fighting.
The dark sphere shattered.
Kaido and Charlotte Linlin burst out of it, furious and slightly claustrophobic, covered in the residual pressure of two minutes of trying to tear through absolute darkness with their bare hands. They broke into open air -- and immediately found Finn, and the barrel.
"Why are we up here?" Charlotte Linlin asked, a beat behind.
Kaido looked at the cannon pointed at them and arrived at the answer faster.
Finn grinned. "Let's see how well you survive this."
"You wouldn't--" Kaido started.
Pluto fired.
The beam that came out of the barrel was not something that had a useful comparison. It was not a laser, not a cannonball, not a conventional energy discharge. It was a column of destruction that moved like light and hit like the concept of finality. It crossed the distance in the time it took to blink, and it was wide enough that whatever space separated Kaido from Charlotte Linlin was irrelevant.
Kaido transformed in the fraction of a second between comprehension and impact. The dragon form erupted from him, every scale reinforced with the heaviest Armament Haki he had ever applied, arms crossing over his chest in a defensive curl that covered everything vital. Every defense he possessed, activated simultaneously.
Charlotte Linlin armored herself completely, Haki surging over her from head to foot in a wave dense enough to be visible. And the arm -- the one she had reattached using her Homies' methods after Finn had severed it, the one with the vast reservoir of soul power she had been holding in reserve as a final trump card, waiting for the precise moment to release it at point-blank range against Finn's skull. She had never found that moment. She detonated it now, releasing the stored soul force as an outward barrier, a second layer of defense between her and what was coming.
An extraordinary last-second adaptation. She spent her trump card on surviving a cannon.
The beam hit both of them.
The dark sky Finn had positioned beyond them absorbed the beam's tail end as it passed through, containing the collateral. The leading edge had already done its work.
Two shapes fell from the sky.
They hit the open ground where Katakuri had been standing before he was sealed. They did not bounce.
Finn descended, his feet touching the scorched earth near the impact site. The magma field still burned around the island's edges. Sakazuki and Newgate were still at it somewhere behind him, audible across the distance, neither apparently willing to acknowledge the concept of stopping.
He walked toward the two shapes.
Charlotte Linlin had landed on her side. Her pink hair was entirely gone -- burned away, all of it, down to nothing. Her clothes were gone in places. The burns across her body were deep and extensive, and in the places where the skin had peeled back you could see pale structure beneath. One arm had separated again. She was not breathing in any way that suggested she had reserves left.
She felt him looking.
She tried to rise. She could not.
Blood came first when she opened her mouth. She cleared it, tried again. More blood. Then, with a visible effort: "Despicable."
"You're a pirate," Finn said. "Don't lecture me about conduct."
She breathed slowly. "What was that thing." Not quite a question. "Marine secret weapon?"
"Pluto," Finn said. "The ancient weapon. The God of the Underworld." He paused. "You've heard of it."
Something moved in her expression -- disbelief first, then a strange and exhausted recognition. "Pluto," she said again, quietly. A long moment passed. "...I see."
Ancient weapons were ancient weapons. Being almost destroyed by one was, in some way, less humiliating than being almost destroyed by a person's own power. She was not certain this was a comfort, but she noted it.
Finn had not brought the right equipment down from the ship. He looked at her, at the spheres floating above him containing Marco and Katakuri, and made a decision.
He extended one arm toward Charlotte Linlin and pointed.
"Planetary Devastation," he said.
The earth responded. Stone and scorched debris rose around her, drawing inward and compressing, dark energy threading through the cracks as it sealed. The sphere closed.
Charlotte Linlin. Big Mom. One of the four people who had shared the top of the ocean for the better part of a decade.
Sealed.
Finn checked his internal sense of time. Less than an hour since they had descended out of a dark sky onto a sleeping island. One Emperor formally down, another sealed. Marco sealed, Katakuri sealed. Sakazuki and Newgate still fighting somewhere behind him, the sounds of it carrying clearly -- neither of them had stopped, and neither sounded like they were about to.
He turned toward the other shape.
Kaido had landed face-down.
He was not moving. The carbonization was complete and uniform -- head to foot, the black of it even and thorough, the kind of result that happened to things that were not designed to survive what had just hit them. No visible breathing. No Haki signature he could detect. No sound at all.
Finn stood over this and looked at it for a moment.
Then he crouched down and gave the figure a measured kick.
The carbonized exterior crumbled where his boot connected. Pieces of blackened material broke away and scattered across the dirt like burned charcoal.
He straightened up.
"That's it?" He looked at the charcoal remains with genuine uncertainty. "You said you were immortal. That was the premise. Where did immortal go?"
He stood there for another moment, scratching the back of his head.
The mythical Zoan ability -- the Blue Dragon, the specific awakened form that Kaido had spent decades developing into something genuinely extraordinary -- was sealed inside that body. If the body was dead, the ability was gone with it. He had been carrying a certain amount of anticipation about that acquisition. It was uncomfortable to have it end in scattered charcoal.
He sighed.
"One shot," he said, to the air. "Two of the Four Emperors." He looked at the Pluto barrel still visible in the dark sky above. "The ancient weapon really is something."
He supposed this was simply Pluto being Pluto. That the Iron Balloon had been reduced to Linlin current state, and the self-described immortal was apparently just ash now, was the ancient weapon demonstrating what eight hundred years of legend had been trying to explain. He could find another mythical Zoan at some later point. The world had more of them.
He filed the loss under acceptable and turned toward the sounds of Sakazuki and Newgate in the distance.
That engagement was taking longer than expected.