The collision left no time for either Emperor to recover.
Arthur and Shanks remained locked together at the center of the ruined harbor, their blades pressed against one another as black lightning crawled across the steel. The force between them continued to pulse outward, scattering dust and splinters across the shattered pier. Beneath their feet, the remaining boards groaned under the pressure, while waves repeatedly crashed against the broken shoreline.
Neither man gave ground as Arthur's two swords strained against Gryphon, one blade holding Shanks' saber in place while the other remained angled toward his opponent. Shanks maintained his one-handed grip, his posture deceptively relaxed despite the tremendous force pressing against him.
For several seconds, they remained like that.
Shanks suddenly twisted his wrist, and Arthur adjusted at once, causing the pressure between their blades to vanish.
Both men moved at the same instant.
Arthur's right sword swept toward Shanks' shoulder while his left followed from below, forcing the red-haired Emperor to retreat half a step. Gryphon deflected the first blade, then turned just enough to intercept the second.
CLANG!
Arthur stepped forward.
Shanks shifted sideways.
Gryphon flashed toward Arthur's neck.
Arthur ducked beneath the strike, his body moving before his eyes had fully registered the attack. He pivoted on his heel and brought both blades upward.
Shanks blocked them.
The impact sent another burst of black lightning across the battlefield.
Neither was surprised.
They had already reached the point where ordinary reactions were no longer enough.
Every movement had to begin before the opponent completed the previous one.
Every opening existed for barely a heartbeat before disappearing again.
Arthur narrowed his eyes.
He's already reading me.
His Kenbunshoku spread through the battlefield.
He felt the movement of Shanks' body, the tension in his muscles, the subtle shift of his weight, and even the direction in which his intent was beginning to form. Yet none of those sensations remained stable for long.
Shanks' presence seemed to disappear from Arthur's perception for a fraction of a second.
Then—
CLANG!
Gryphon struck from the side.
Arthur caught it with his left sword.
Shanks immediately followed with a second attack.
Arthur's right blade intercepted it.
The two swords collided almost simultaneously.
Shanks' eyes narrowed.
Arthur's expression remained focused.
Neither had spoken.
They didn't need to.
Their Haki had already become the language of the duel.
Arthur suddenly saw it.
A possibility.
Shanks stepping forward.
Gryphon descending diagonally.
Arthur moving his right foot backward.
Then another possibility replaced it.
Shanks changing direction.
A thrust toward his chest.
Arthur turning his shoulder.
Then a third.
A feint.
Arthur's eyes sharpened.
Future Sight.
The world seemed to slow around him—not because time had changed, but because his perception had already reached the moment before it happened.
Shanks stepped forward exactly as Arthur had perceived.
Arthur shifted his body.
Gryphon passed through the space where his chest had been.
Arthur's left sword immediately swept toward Shanks' side.
Shanks withdrew.
Arthur's blade missed by inches.
A faint smile appeared on Shanks' face. "So you're using it."
Arthur said nothing.
He advanced.
His two swords moved in succession, one creating an opening while the other attempted to exploit it. Shanks blocked the first, avoided the second, and answered with a single slash aimed directly at Arthur's center.
Arthur had already seen it. He moved before the attack was fully launched. The blade passed harmlessly beside him.
But Shanks was already somewhere else.
Arthur's Future Sight showed nothing. His expression changed. Gryphon appeared behind him. Arthur spun around and crossed both swords.
BOOM!
The impact drove him backward.
His boots tore through the earth before he regained his balance.
Shanks did not pursue immediately. He stood several meters away, Gryphon lowered at his side.
Arthur stared at him.
Something was wrong.
He had seen the attack.
No—
He had seen several possible attacks.
But he hadn't seen that one.
Arthur's Kenbunshoku expanded again.
There was nothing.
No clear intention.
No stable image of what Shanks would do next.
Only a faint, distorted presence.
Across the battlefield, Shanks' expression remained calm.
Arthur finally understood.
He's interfering with my Observation.
Shanks moved.
Arthur's Future Sight activated again.
For an instant, the world ahead of him fractured into possibilities.
Shanks attacking from the left.
From the right.
A direct thrust.
A feint.
A delayed strike.
Too many possibilities appeared at once.
Arthur's concentration tightened.
Then every vision vanished.
Shanks was already in front of him.
CLANG!
Arthur barely caught Gryphon.
The force pushed him backward.
Shanks followed with another strike.
Arthur blocked.
Another.
He parried.
A third came from an angle his Future Sight had failed to reveal.
Arthur twisted his body.
The blade grazed his coat.
A thin cut appeared across the fabric.
Shanks withdrew.
Arthur looked down at the damaged coat for half a second before raising his eyes again.
Shanks smiled faintly. "Your Future Sight isn't enough."
Arthur's gaze hardened. "I figured that out already."
The red-haired Emperor lowered Gryphon slightly. "Then what are you going to do?"
Arthur tightened his grip.
He didn't answer.
Instead, he closed his eyes.
The watching pirates immediately noticed.
Law's brow furrowed. "What is he doing?"
Robin watched Arthur carefully. "He's not relying on his eyes."
Kuina's attention sharpened. "He's expanding his Observation."
Beckman said nothing.
He understood what Arthur was attempting.
Arthur stood perfectly still as the sounds around him gradually faded—the crashing waves, the wind, the movement of the crews, and even the distant creaking of damaged wood.
He focused on something deeper.
Kenbunshoku Haki wasn't merely about seeing. It was about sensing presence, intent, and will beyond what the eyes could perceive.
Arthur had spent years refining his Observation until he could distinguish countless details within a battlefield. He could sense movement before it became visible, feel hostility before an attack was launched, and glimpse possible futures through the flow of his opponent's actions.
But Shanks had shown him the weakness in that approach.
Future Sight could only reveal what his Observation could perceive.
If the perception itself was disrupted, the future became uncertain.
Arthur slowly opened his eyes.
Shanks was watching him.
For the first time, the faint smile on the Emperor's face disappeared.
Arthur had understood something.
The answer wasn't to see farther. It was to prevent Shanks from hiding the intent behind what he was about to do.
Arthur's Conqueror's Haki began spreading through his Observation.
The pressure was subtle at first.
Almost imperceptible.
But Shanks felt it and his eyes narrowed.
Arthur stepped forward. The atmosphere around him changed. His Kenbunshoku no longer felt like simple perception.
It carried his will.
A pressure that reached beyond the surface of Shanks' presence and pressed against the very flow of his Observation.
Shanks' expression became serious.
Arthur smiled faintly. "I think I understand now."
Shanks raised Gryphon. "Understand what?"
"How you've been hiding from my Future Sight." Arthur's two swords lowered slightly.
For the first time, Shanks' eyes showed genuine interest.
Arthur's Conqueror's Haki intensified.
Black sparks flickered around his body.
"You're not hiding your movements." He took another step. "You're hiding your future."
The air seemed to tighten.
Shanks' smile slowly returned. "Then show me."
Arthur's eyes sharpened.
The next instant, both Emperors vanished.
BOOM!
The battlefield erupted once more. But this time, Arthur no longer fought the future Shanks showed him. Arthur no longer chased the future Shanks showed him. He attacked the space where Shanks' intent was forming.
Shanks' eyes widened slightly.
Gryphon came up just in time.
CLANG!
Arthur's first sword collided with it.
His second followed immediately.
Shanks deflected it.
Arthur changed direction.
Shanks shifted.
Arthur followed.
For the first time, Shanks was being forced to react to Arthur's perception rather than control it.
From the edge of the battlefield, Beckman's expression changed.
"He figured it out."
Law glanced at him. "Figured what out?"
Beckman's eyes remained fixed on the duel.
"Shanks has been suppressing his presence through Observation Killing."
Robin's gaze sharpened. "And Arthur has found a way to interfere with it."
Kuina understood immediately. "So they're both fighting without allowing the other to see the complete picture."
"Exactly." Beckman nodded.
Another explosion shook the ruined harbor.
Arthur and Shanks crossed blades again, black lightning bursting between them.
This time, however, Arthur's movements were no longer being dictated by the future Shanks allowed him to see.
He was beginning to see through the silence.
And somewhere within that silence, Arthur felt the shape of a new technique taking form.
A technique born from the combination of Observation and Conqueror's Haki.
Arthur's eyes narrowed.
If he can blur his presence...
His two swords tightened in his hands.
Then I'll blur my future.
Shanks' gaze sharpened from across the battlefield.
Neither Emperor spoke.
They simply charged again.
And as their blades collided beneath the darkening sky, Arthur took the first true step toward mastering Observation Killing.
Shanks did not give Arthur time to settle into his new understanding.
The moment Arthur's two swords came forward, Gryphon answered. The red-haired Emperor crossed the distance with a sudden burst of speed, his single blade cutting toward Arthur's center. Arthur met him head-on, bringing one sword across his body while keeping the second angled behind it.
CLANG!
The impact rang across the ruined harbor.
Arthur immediately felt the difference.
Shanks' movements had become harder to read.
Not faster.
Not necessarily stronger.
More deliberate.
Every motion seemed to contain several possibilities at once, forcing Arthur's Observation to distinguish between genuine intent and deliberate misdirection. Shanks was no longer simply hiding his future. He was controlling how much of that future Arthur was allowed to perceive.
Arthur twisted one blade around Gryphon and redirected the strike. His second sword followed immediately, forcing Shanks to turn his wrist and deflect it.
The two separated.
Arthur did not pursue blindly.
He waited.
His Kenbunshoku spread through the battlefield once more, searching beyond Shanks' physical movements. He felt the shift of his feet, the tension in his shoulder, the subtle pressure of his Haki. Yet the information remained incomplete.
Shanks had become strangely quiet within Arthur's perception.
Arthur understood why.
Observation Killing.
It wasn't simply the ability to hide one's presence. At a higher level, it could interfere with the opponent's ability to construct a reliable picture of the future.
Shanks had spent years refining that control.
Arthur had only just begun to understand it.
Shanks suddenly stepped forward.
Arthur's Future Sight activated.
A possible future appeared.
Gryphon descending from above.
Arthur moved to intercept.
The image disappeared.
Another possibility surfaced.
A horizontal slash.
Arthur shifted his stance.
That vision vanished as well.
A third possibility emerged.
A thrust directly toward his chest.
Arthur moved—
But Shanks wasn't there.
The red-haired Emperor had already changed direction.
Arthur turned just in time.
CLANG!
Gryphon struck his left sword and sent it outward.
Shanks followed with a second motion, but Arthur's remaining blade rose beneath the saber and stopped it before it reached his body.
For a brief instant, their faces were only a few feet apart.
Shanks smiled. "You're starting to see it."
Arthur's eyes remained fixed on him. "I'm starting to understand it."
"That's different."
"Very."
Arthur pushed Gryphon away.
Both men retreated.
Around them, the ruined harbor had fallen strangely quiet. The earlier destruction had driven most of the spectators farther from the battlefield, leaving the two Emperors surrounded by broken timber, torn earth, and drifting dust.
Law watched from the edge of the safe zone.
"They're barely looking at each other anymore."
Robin's eyes remained on the duel. "Because they don't need to."
Law glanced toward her.
"Observation Haki allows them to sense what their eyes cannot."
Kuina nodded. "Their eyes are only confirming what their Haki has already detected."
Beckman folded his arms.
"At this level, looking at the opponent can actually be slower than sensing him."
A sudden burst of movement interrupted the conversation.
Arthur and Shanks collided again.
This time, neither launched a prolonged sequence of attacks.
One strike met one response, followed by another exchange and a precise counter before they separated again.
Their movements were becoming increasingly economical.
Arthur's Nitoryu created constant pressure from two directions, forcing Shanks to account for both blades simultaneously. Yet Shanks' one-handed swordsmanship compensated with extraordinary efficiency. He didn't attempt to match the number of attacks. Instead, he waited for the smallest opening and used a single precise motion to dismantle Arthur's rhythm.
Arthur recognized the principle.
He's making me spend more movements than he does.
His right sword came down.
Shanks parried.
Arthur's left blade immediately followed.
Gryphon shifted.
Arthur reversed the direction of his right sword.
Shanks stepped back.
Arthur advanced.
The distance disappeared.
Their blades crossed again.
CLANG!
Shanks suddenly released a burst of Conqueror's Haki.
Arthur's perception trembled.
For an instant, Shanks' presence seemed to vanish completely.
Arthur's eyes narrowed.
There.
Not ahead.
Not behind.
Nowhere his Observation could clearly reach.
Arthur stopped relying on Future Sight.
Instead, he focused on the pressure itself.
He could feel Shanks' will.
Faint.
Controlled.
Almost deliberately buried.
Arthur followed it.
His left sword moved before his eyes found the target.
CLANG!
Gryphon appeared against the blade.
Shanks' expression changed slightly.
Arthur smiled. "Got you."
Shanks' eyes sharpened.
Arthur immediately followed with his second sword.
Shanks withdrew.
The blade passed within inches of his chest.
For the first time, Arthur had attacked the location Shanks was actually occupying while his Observation was being suppressed.
Shanks landed several meters away. He looked at Arthur for a moment. Then his grin returned.
"You're learning quickly."
Arthur lowered his swords slightly. "I don't have much choice."
"Fair." Shanks raised Gryphon.
The pressure around him changed again.
Arthur felt it immediately.
His Observation became heavier.
Not blocked.
Challenged.
Shanks was pushing his own will directly against Arthur's perception.
Arthur responded instinctively.
His Conqueror's Haki expanded.
The two pressures met before either man moved.
The air between them distorted.
Dust lifted from the ground.
Loose fragments of wood rose and hovered for an instant before scattering in every direction.
Law's expression tightened.
"Captain Arthur using Haoshoku through their Observation."
Robin nodded. "He's not simply sensing each other anymore."
"Then what is He doing?"
"He's fighting for control of what the other is allowed to sense."
The explanation made Law's expression harden.
He looked back toward the battlefield.
Arthur and Shanks still hadn't moved.
Yet their Haki was already colliding.
To someone without advanced Observation, nothing appeared to be happening.
But to Arthur, the battlefield had become a storm of invisible pressure.
He could feel Shanks searching for him.
He could feel the red-haired Emperor attempting to suppress his presence.
Their wills collided.
For a moment, Arthur caught a glimpse of Shanks' intent.
Not an attack.
A feint.
Arthur almost smiled.
He waited.
Shanks moved.
Arthur did not.
Gryphon cut through the space beside him.
Shanks' eyes widened slightly.
Arthur's right sword flashed toward his ribs.
Shanks twisted away.
The blade missed.
But Arthur's second sword was already waiting.
Shanks barely raised Gryphon in time.
CLANG!
The force pushed him backward.
Arthur followed.
One sword attacked.
The other controlled the space around it.
Shanks blocked the first.
The second forced him to retreat.
Arthur changed the rhythm.
Shanks adjusted.
Arthur accelerated.
Shanks answered.
Their exchange became a silent contest of perception.
Neither was simply trying to strike the other anymore.
Each was attempting to control what the opponent could perceive before the attack even began.
Arthur's understanding deepened with every exchange.
Observation doesn't have to reveal the future.
His eyes followed Shanks' movement.
It can prevent the future.
Arthur's Conqueror's Haki flowed into his Kenbunshoku again.
The pressure around him became sharper.
More focused.
More intentional.
Shanks sensed it.
His smile disappeared.
Arthur moved.
This time, there was no hesitation.
He didn't wait for a future vision.
He didn't search for an image.
He reached directly for Shanks' presence and pressed his own will against it.
Shanks' perception flickered.
For the briefest instant, Arthur felt the same sensation he had experienced earlier.
The future became incomprehensible.
But this time—
It wasn't Shanks who had caused it.
Shanks' eyes widened.
Arthur had done it.
He had successfully disrupted Shanks' Observation.
The realization passed between them without a single word.
Arthur's grip tightened around his swords.
Shanks' expression slowly changed into a genuine smile.
"Now you've got it."
"I think I do." Arthur stepped forward.
Their Haki surged.
The next exchange came faster than anything before it.
Arthur's two swords crossed toward Shanks from opposite angles. Gryphon intercepted one, then the other, but Arthur had already altered the timing. He pulled one blade away and redirected the second before Shanks could regain his rhythm.
Shanks moved on instinct.
Arthur followed the pressure of his will.
CLANG!
Gryphon collided with the first sword.
Arthur's second blade passed close enough to tear another section of Shanks' coat.
Shanks twisted away.
Arthur stopped.
The red-haired Emperor landed lightly several meters away.
He looked at the damaged fabric, then back at Arthur.
Neither man spoke.
But the answer was already clear.
Arthur had crossed the first threshold.
He had not merely resisted Shanks' Observation Kill.
He had begun to reproduce its principle.
From the edge of the battlefield, Robin quietly exhaled.
"He's done it."
Law looked toward her. "Observation Killing?"
"Not perfectly yet. But enough." Robin nodded.
Beckman's eyes remained on Arthur. "Enough is all it takes."
Arthur heard none of them.
His attention remained entirely on Shanks.
The red-haired Emperor raised Gryphon once more.
His expression was calm, but his eyes had changed.
The testing phase was over.
Arthur had discovered how to interfere with Shanks' greatest observational advantage.
Now Shanks would have to find another way to break through Arthur's defense.
And as the two swordsmen slowly moved toward each other again, Arthur felt the next layer of their battle beginning to reveal itself.
Observation had reached its limit.
The answer would come from another form of Haki.
Armament.