The pirates within Impel Down's sea-level first floor could not be killed without direct authorization. Otherwise, Rain Shiryu would never have ended up imprisoned on the sixth floor in the future.
But this time, if these pirates dared to escape again—Akainu would show no mercy.
This was the first floor built atop the sea.
Behind Akainu and his forces stood a massive iron fence, behind which was a colossal gate, and beyond that gate—endless ocean.
As Akainu's stern voice fell, an oppressive silence settled over the scene.
No one doubted Akainu's words. His strength was unquestionable—he had built his reputation in the New World, enough to send shivers through the bones of even the most hardened pirates.
"The brat from back then has grown into something terrifying," said Red Earl, his voice calm as his eyes swept over the navy soldiers behind Akainu. The stillness in his face belied the surge of Haki that exploded from him a moment later.
A terrifying wave of Conqueror's Haki swept through the air.
Plop.
Plop.
Plop.
One by one, weaker navy soldiers collapsed unconscious to the ground, unable to withstand the pressure.
Yet, beside Akainu stood over ten Vice Admirals and a second row of composed Rear Admirals. Their expressions didn't change in the slightest. Even under the Red Earl's domineering aura, their eyes remained calm and steady.
Akainu responded without emotion. "Since you were captured and sent to Impel Down, you should spend the rest of your life here. Why leave?"
"Ah, but we are beings of the sea," Red Earl replied. "It is our only true home."
Akainu sneered. "You're nothing but filth that pollutes it."
"You should say that to the World Government," Red Earl chuckled. "Let's see if you have the guts to repeat it to those Celestial Dragons."
Hearing that, Akainu snorted coldly. The magma swirling around his body surged hotter. "Enough nonsense. Either put on the sea stone handcuffs and return to your cell—or I'll send you to your death."
"Your strength isn't enough to kill us," said Bullett, his voice low and steady.
A monstrous aura burst from Bullett's body. His Conqueror's Haki mixed with his highly advanced Armament Haki, released into the open.
The sheer force of it made the magma lake in front of them ripple and churn, drawn toward Akainu by the force of Bullett's overwhelming presence.
"Hmph."
Akainu's expression darkened. "So, you've made your choice."
The temperature rose sharply as intense magma surged from Akainu's body. Without hesitation, he punched forward—his right arm wrapped in blazing magma, forming a gigantic fiery fist.
Bullett didn't speak another word. He clenched his right hand, Armament Haki instantly covering his arm. He stepped forward and launched a punch of his own.
A violent shockwave burst from the collision—air distorted and howled, a powerful clash between monsters.
Boom!
The impact shook the magma lake itself.
"It's useless to keep talking. Let's see how many of us you can stop," Mio grinned, slamming his palms into the ground beneath him.
Buzz… Buzz… Buzz…
A strange circular light spread out from Mio's position, expanding rapidly.
"Captain of the Black Crow Pirates… Kurokawa Mio," Akainu muttered, his eyes narrowing.
He had originally underestimated this young pirate. But seeing Mio now—standing in the center of the most dangerous criminals on the sixth floor—Akainu's heart sank.
This man was more dangerous than intelligence had led them to believe.
"Replacement!" Mio called out with a confident smirk.
Buzz.
The moment the word left his lips, the Red Earl grabbed a random pirate by the arm and yanked hard—ripping it clean off and flinging it over the magma lake.
A split second later—
Buzz!
Mio's ability activated.
Within the glowing circle, the massive gate behind the iron fence—Impel Down's rear gate—suddenly vanished.
It was replaced by the pirate's severed arm.
At the same time, a massive gate appeared in midair above the magma lake and crashed down with a thunderous bang, creating a makeshift bridge across the molten lava.
The thick iron gate resisted the magma's heat—at least for the time being—forming a new path.
"What?!"
Akainu's pupils shrank, shock flashing across his face. "This ability…"
He looked from the disembodied arm to the gate on the magma. "A space-related ability?"
Mio paid no attention to Akainu's stunned expression. He slowly stood, clapped his hands, and grinned. "Looks like a year of training paid off. Get up, everyone. Whether or not we escape Impel Down next time depends on you."
This was the second stage of Replacement: Object Substitution.
Some of the old monsters on the sixth floor were aware of Mio's ability development. That's why they feared him.
Over the course of a year, Mio had successfully refined his Devil Fruit powers to this level.
And this ability wasn't just limited to swapping gates.
It could do far more.
As Mio's words rang out, the pirates who had stood quietly outside the elevator earlier were momentarily stunned. Then—bloodthirst filled their eyes.
"That's right! Whether we get out or not—it depends on us!"
"Kill the bastards!"
"Charge! Damn navy scum!"
The pirates roared, charging forward.
The navy soldiers didn't hesitate. They drew their weapons and engaged the chaotic onslaught.
Still, Akainu and the Vice Admirals did not move—yet.
They simply watched Mio and his companions.
"What now?" Mio asked with a helpless shrug, looking at the Red Earl.
"What else? Kill and charge at the same time." An old pirate from the sixth floor grinned, stepped forward, and rushed straight toward a Vice Admiral.
"Hmph." The Vice Admiral snorted coldly, drawing his weapon and launching an attack.
Red Earl nodded in approval at the old pirate's response, then turned to Bullett.
"You want to take Akainu?"
"If you want him, I'll let you have him," Bullett replied, lifting his eyes.
Red Earl shook his head lightly. "Troublesome enemies like him are better suited for you. I'm starting to envy you guys with Devil Fruit abilities. If I escape, I'll find a good fruit myself."
"Talk about it after we escape," Bullett replied, then vanished.
Boom!
He reappeared instantly in front of Akainu. Their fists clashed violently once more.
The Vice Admirals of the navy also sprang into action, each seeking out an opponent.
The Rear Admirals worked in groups, surrounding stronger enemies to stall them and search for an opening.
But just then—
Outside the back gate, several figures slowly appeared.
Mio's lips curled upward in a smile.
At last, his eyes lit up. "Finally, we meet… my friends."