Impel Down, the world's greatest prison, stands in the Calm Belt of the first half of the Grand Line. Its security is absolute.
The prison itself is a colossal tower that descends into the sea, its foundation rooted deep on the ocean floor. Because it lies within the Calm Belt, it is naturally surrounded by massive Sea Kings. A Marine battleship fleet guards its perimeter at all times.
The structure is divided into multiple underground levels. In the dark corridors lie countless cells and interrogation chambers. Every cell is reinforced with Seastone to suppress Devil Fruit abilities and prevent escape.
Surveillance Den Den Mushi are installed throughout the prison. Their vision is transmitted to a central monitoring system, where larger Den Den Mushi project the images onto screens for the guards. Each small Den Den Mushi is equipped with an alarm buzzer in its shell.
Combined with the powerful jailers stationed inside, this has earned Impel Down its reputation as an "Impenetrable Iron Wall."
It is said that since its founding, no pirate or criminal has ever escaped.
Whether that claim is entirely true is another matter. Impel Down has existed for over a century. Even if someone had escaped, the World Government would have buried the truth. Like Enies Lobby, Impel Down represents the Government's authority and image.
Tonight, however, the world's largest prison welcomed uninvited guests.
"Is this Impel Down? The defenses are impressive," Nelson muttered as he looked down from the sky.
From above, only the uppermost structure was visible. The majority of the prison lay submerged beneath the sea.
There was only one entrance and one exit. A massive steel gate.
A fleet of Marine warships formed the first line of defense. Any assaulting force would have to break through them first.
Although no Marine Vice Admirals were stationed here permanently, the officers guarding Impel Down were formidable. Many likely possessed strength comparable to Vice Admirals and were serving here to accumulate merit.
"Impressive?" Redyat chuckled. "We're about to walk in."
"Then let's be the ones who shatter its myth," Teach said quietly, eyes gleaming.
It was night, but darkness meant nothing to him.
Only three people had come. Teach, Redyat, and Nelson.
Teach used gravity to remain airborne. Redyat could fly during the day and move freely through shadows at night. Nelson remained concealed within Redyat's shadow space.
This operation required Nelson's ability.
They bypassed the natural defenses with ease. The Gates of Justice, the whirlpool currents, and the Sea Kings of the Calm Belt were meaningless obstacles when approached from the sky under cover of darkness.
The iron triangle of Enies Lobby, Marine Headquarters, and Impel Down was rendered irrelevant.
"We begin infiltration," Teach said calmly. "I won't release Observation Haki here. Redyat, this is your stage."
Observation Haki could not sense those hidden within shadow space. And at night, shadows were everywhere.
Redyat nodded.
As he gazed down at the prison, a faint tremor stirred within his blood.
His father was below.
A man he had never truly known.
This would be their first meeting.
Yet his heart remained strangely calm.
Deep beneath the sea, on Level Six of Impel Down, the Infinite Hell, a middle-aged man leaned against the cold stone wall of his cell.
His wrists and ankles were bound with Seastone shackles. Thick chains secured him in place, and Seastone spikes pinned his limbs.
Suddenly, he shifted slightly.
The chains rattled.
The sound echoed in the suffocating silence of Infinite Hell.
In neighboring cells, pairs of tightly closed eyes opened.
The prisoners here conserved energy obsessively. Excess movement meant wasted strength. Hearing movement from that particular cell was unusual.
"That monster moved."
"Is he planning something?"
"Escape?"
Level Six housed only the worst criminals in history. Death row inmates. Erased legends. Names deliberately removed from newspapers.
Among them was one figure whose reputation dwarfed the others.
"Red the Aloof ," Patrick Redfield.
If anyone had even the slightest chance of escaping, it would be him.
Still, hope was a dangerous thing in this place.
Redfield was under extreme restraint. Even if freed from Seastone, how much strength could he still muster after years of confinement?
Most prisoners here had long since fallen from their peak.
Yet boredom was worse than despair. Even speculation offered relief.
Redfield slowly lifted his head.
His gaze seemed to pierce upward, through layers of hell, through rock and seawater, to the surface above.
He had already sensed them.
Father and son.
Though separated by stone and steel, their awareness intersected.
A faint smile curved Redfield's lips.
In the monitoring room on Level Four, Blazing Hell, a jailer frowned at the surveillance feed.
"Something's off. Redfield moved."
"Relax," another jailer replied. "They complain from time to time. If we run to the Chief Warden over every twitch, we'll look incompetent."
The first jailer hesitated, then nodded. "We'll monitor closely."
Den Den Mushi rotated their heads, scanning every corner of Infinite Hell.
The monitoring station on Level Four was dedicated specifically to Level Six. The threat level there demanded constant vigilance.
The current Chief Warden was Acel.
A veteran who had served in Impel Down for over forty years, Acel had become a jailer at twenty and Chief Warden in his forties. Now over sixty, he was the living embodiment of Impel Down's iron authority.
His Devil Fruit ability was the Paramecia-type Connect-Connect Fruit.
Through it, he could link individuals within Impel Down, criminals and jailers alike. He monitored movements through these connections.
Upon awakening his ability, he gained a terrifying power called Life Connect. Damage inflicted upon him could be distributed across those connected to him.
Within Impel Down, he was nearly invincible.
Some years ago, after the defection of one of Impel Down's three prodigies, King, who later joined the Beasts Pirates, Acel was temporarily demoted. It was largely symbolic. His record remained unmatched.
Impel Down had once trained three monsters to parallel the Marines' rising Logia prodigies.
Shiryu of the Rain, a genius swordsman proficient in Rokushiki.
Magellan, wielder of the Venom-Venom Fruit.
And King, an Ancient Zoan user with immense physical power and natural flames.
Now King was gone. The other two remained.
Above Impel Down, Redyat exhaled slowly.
"Let's move."
Shadows enveloped Teach and Nelson, pulling them into shadow space.
From within, they could see the outside world as though watching through a translucent veil.
Redyat's body dissolved into pure darkness.
The shadow slipped along the ground, unseen, and reached the massive gate. It flowed through the narrow gap beneath it and entered Impel Down without a sound.
In the pitch-black corridors, the shadow blended seamlessly. Even beneath the gaze of Den Den Mushi, detection was unlikely.
Its speed exceeded normal perception.
They reached the elevator shaft and descended along the structure to Level Five, Freezing Hell.
This level imprisoned pirates with bounties exceeding one hundred million Berries. Temperatures were lethally cold. Prisoners suffered frostbite until death. Packs of Military Wolves roamed the frozen forest.
No Den Den Mushi were installed here. They could not survive the extreme cold.
From there, Redyat located the hidden access route to Level Six.
Infinite Hell could not be reached by ordinary elevator. Only a handful of officials possessed the necessary authority and keys.
For Redyat, walls meant nothing.
The shadow seeped through the ceiling and descended into the darkness of Infinite Hell.
Few prisoners here retained peak condition. Most were diminished by time and restraint.
Redyat's current strength surpassed nearly all of them.
He moved directly toward the deepest cell.
If he wished to remain hidden, almost no one could detect him. Observation Haki could not penetrate shadow space.
Almost no one.
Except one.
Redfield had sensed them long before they arrived. Not through Haki alone, but through instinct.
The shadow slipped along the wall and entered the final cell.
Inside, chained and restrained, sat the legendary pirate.
Patrick Redfield awaited them.