Without any regard for the consequences, in the battle that would decide both their fates, he had burned through what should have been his greatest power: the Unique Skill he had pieced together as a mere mortal, a miracle that should never have belonged to him.
One Blade, Heart Eater had forcibly ended Severing Blade. Once Severing Blade had been activated, Infinite Sword would also turn gray, sealed and unusable for the next hour.
He had paid that price.
Kayaba frowned as he looked down at the shattered remains of the crimson shield, now breaking apart into meaningless crystal fragments.
Just to destroy this shield...?
No wonder Satoru had not cared at all whether Kayaba could read his attacks. He had simply poured out one Sword Skill after another at blinding speed. His target had never been Kayaba himself. It had been the crimson shield's durability. In the end, he had even sacrificed his own Unique Sword to defeat Holy Sword.
Kayaba's brow furrowed deeper.
"I never imagined... that beneath the surface, your pride would run this far."
The left hand that had always carried Kayaba's invincible defense now hung empty. He stared straight at Satoru, who held Sakura Fang with an expressionless face.
"That is the kind of person I am," Satoru replied evenly. "I move from one online game to the next, defeating players, and eventually turn my blade toward the developers. Usually, my victory means forcing them to release a patch. This time is just a little more exciting."
"Heathcliff was already dead the moment you revealed his identity."
"Then consider this me beating the corpse for my own amusement." Satoru gave a cold scoff.
Kayaba looked at him, then could not help laughing softly.
"But if Heathcliff's power was Holy Sword, what do you think you need in order to defeat Kayaba?"
"Simple. Bring out something only Kayaba can use." Satoru said it plainly. "For example, the support functions you wrote for yourself."
Kayaba paused, genuinely surprised.
"Are you serious...?"
"Of course." A cold smile traced Satoru's mouth. "Yurnero and Heathcliff, Infinite Sword and Holy Sword, have already settled their match. What comes next is naturally the battle between Satoru and Kayaba."
It was arrogance enough to be called a crime.
"Using the skill I created to defeat me and humiliate me still was not enough. Now, at the very end, you intend to challenge me as the administrator with authority over the entire game?"
Kayaba narrowed his eyes.
"Do you mean to kill all of Aincrad here?"
"This has always been my way. Nothing more."
"You are nothing like you were before. This could only be called reckless." Kayaba's voice was cold now. "No matter how fast you are, no matter how many Sword Skills you chain together, if I give myself the Immortality Command again, everything you do becomes meaningless."
"Is that so?" Satoru nodded. "Then that only means you will keep suffering pain from the depths of your soul."
His golden eyes fixed on Kayaba.
"The line between life and death, the road between survival and extinction. From this second on, this becomes an even crueler killing match. Every cut Sakura Fang makes from here will land on your soul, sever your mind, and grind your nerves apart. If you truly believe you have the will to withstand a hell of blades and fire, then add the Immortality attribute with pride."
There was an unsettling smile in his voice.
"This is not a joke. It is a warning left by those who came before. An immortal weakling is nothing but the eternal plaything of the strong."
The man opposite him listened in silence.
"A warning from someone who stepped into the Fluctlight Domain, then."
He began to laugh, and that laughter only grew louder.
His left hand, now free of the crimson shield, pulled a menu out of thin air. Without even looking, he tapped through option after option with mechanical precision, activating functions at terrifying speed.
Sword Skill Calibration System: enabled.
Avatar Adaptability Optimization: enabled.
FullDive Resources: adjusted to maximum.
Limit Acceleration Assist: raised from Level 3 to Level 8.
Neural Read Extraction Stimulus: adjusted from Safe to Dangerous.
Automatic Mental Care System: disabled.
"As this world's highest-ranking observer, of course I watched the entire course of your battle with Kaizuka, Suzuki-kun. Even before that, I had already formed a rough theory regarding Fluctlight acceleration."
Kayaba spoke loudly. His voice sounded strained, as though he were enduring something, yet he never wavered. His left hand continued scrolling steadily down the menu, unlocking balance-breaking functions with a kind of madness.
"Indeed, when a person's mind is forced into a state of heightened stimulation, the speed of thought multiplies. Time dilation begins to operate in the brain. Vision slows, the will concentrates, and in an instant one can think, judge, and decide. In the real world, however, such divine speed of thought is still limited by the reaction ceiling of the physical body."
"But in a FullDive environment, where every instruction from the brain is transferred by my program into a virtual body, everything changes."
Kayaba began to breathe as if in pain.
"As long as this virtual body does not reach zero HP, it exists according to the rules. It guarantees that the soul dwelling within it, having reached the realm of man and god, may bloom without restraint. Only a fantasy world born from science could allow humanity such abandon."
"A soul freed from its restraints has tremendous power to gather information. I imagine the brain is being forced to operate at a frantic rate as well..."
He hissed through his teeth.
"If it were only one person, that would be one thing. But if two people are in that state, and both of them want to send the other into the grave... two people made hypersensitive to external information, both consumed by fury, can almost be said to be tearing each other's souls apart."
"And if the opponent were merely an ordinary person who could not feel your rage and killing intent, they would not feel that pain in the soul. They would simply lose to sword speed that surpasses the system."
"That is the risk and price resonators bear when they enter this state."
"The Fluctlight Domain. In this Aincrad, it is the strongest skill any player can develop, though I never set it there in the first place... It simply came into being on its own in this first FullDive otherworld."
Kayaba slowly raised his head. His golden eyes flickered unsteadily, yet they looked almost the same as Satoru's.
For the first time, realization showed on Satoru's face.
"So unless your opponent is the same type as you, your anger cannot reach them so easily." Kayaba clenched his teeth, his face beginning to twitch.
"In other words, that PoH guy is the same..." Satoru said in a low voice.
"That is exactly what I mean. Because you lacked information, you made a slight error in judgment. After all, even you cannot force yourself into this state in every battle."
"However, rather than saying he is the same type as you and Kaizuka, it would be more accurate to say you forced him into it, just as Kaizuka's existence forced you."
"Then what do you mean by doing this now?"
"I am not as skilled as you two in this field, but by using the system to forcibly stimulate my brain nerves, I can just barely reach it... even if it feels as though an explosion full of razor blades has gone off inside my skull." Kayaba spoke haltingly. "I never expected the position to reverse. This time, the one using every ability he has just to catch up with a genius is me."
"If you did not do that, would you not avoid the pain of being hit?"
"Heh... heh heh. You have your arrogance, and I have my pride." Kayaba's eyes widened, the gold in them flickering in and out. His entire body trembled as he answered one word at a time. "This is the world I created. This is my ideal. How could I possibly step back now?"
"I see."
"Then experience the possibilities of your ideal world for yourself."
Satoru stepped forward.
"Kayaba."
The words fell.
He was already gone.
Yurnero's virtual body seemed to be pulled apart by a tremendous force. It did not break, but it was no longer shaped like a proper human being. The soul dwelling within that false body had conveyed the will to charge, and the virtual body faithfully tried to obey. It simply could not keep up.
Kayaba's virtual body, Heathcliff, twisted into the same distorted shape.
But in the instant they brushed past each other, Kayaba's left arm was severed and sent flying high. Absurdly enough, because it was now a severed limb and no longer needed to execute combat commands, the system that finally caught up restored the arm to its normal structure. It struck the ground, rolled several times, and dissolved into crystal fragments.
Everyone stared blankly in that direction.
This time, they truly could not see anything.
It was not like before, when the two figures had moved so fast they made the eye blur.
They could not even see the chaotic shadows anymore.
All that remained was black and red twisting and tearing together, the most distinctive colors of Yurnero and Heathcliff's outfits.
The nerve-raking clang of swords crashing together was gone as well. It was almost silent, except for a sound like wind passing softly through the air.
It was not that invisible ghosts were fighting. There was simply too little for the eye to catch, so little that it could not form an image.
A silent battlefield.
And yet, the unease in their hearts never vanished. As if by illusion, inside that quiet wind brushing past their ears, they could hear human roars and screams.
It sent a chill down the spine.
...
Pain.
Tearing pain.
Pain as if the entire body were being pulled apart and crushed.
It surpassed anything language could contain. If this had been real, he would have fainted long ago.
Yet the truly maddening thing was that even inside this agony, even as if dragged into hell itself, he could still see the sword before him and still think through how to counter it. The soul was so resilient... and so fragile.
Kayaba's body was being cut apart piece by piece. This virtual body was being destroyed, and his HP bar was falling beyond all hope of stopping it.
And yet, it was a sensation so intoxicating that one might willingly cast everything else aside for it.
Human potential...?
Ah...
In a daze, Kayaba suddenly thought of something.
Perhaps.
Perhaps the Seed he and Rinko had discussed before was not an advanced autonomous artificial intelligence after all. That child's growth was far too much like that of an ordinary person. There was nothing mechanical about it, as though it had emotion and affection. In exchange, it seemed to have lost the overwhelming power a perfect intelligence should possess.
It had lost the capacity to store all of human history, lost the ability to think through tens of thousands of years in a microsecond, lost the qualification to reach godhood through intellect.
The true Seed... was the fact that a human had stepped into this realm for the first time.
In that blurred, illusory field of vision, his thoughts spread out before him like frames of film.
Precisely because of that, precisely because he was in this realm, he could be certain.
He had already lost.
The HP of this virtual body, Heathcliff, would reach zero in 266.24 seconds.
It was a number and a conclusion he could reach with a simple thought.
Or rather, the result of his defeat was still moving steadily forward.
Because Satoru was getting faster.
Even after entering that empty, desolate realm, he kept racing on.
In this instant, he had already surpassed Makoto Kaizuka's adaptability. If time had been turned back two years, he would have been the wielder of Life-Farewell Halberd... Ha. In that case, Infinite Sword would never have been obtained by anyone, would it?
Should he continue?
Satoru.
Or...
You cannot stop now.
Unfortunately, human beings can never become gods. If they never pause, they will burn out.
Well... this was your victory from the start.
Let us end it.
The gold in Kayaba's eyes began to dim.
Along with this sky city.
...
I cannot see anything.
A sea of white.
It feels a little warm.
But now it is scorching.
This world seems endless.
I cannot even see myself anymore.
When I look down, I cannot see my chest, my waist, my abdomen, my lower body, or my hands.
Is it because the white light hides them, or because they no longer exist at all?
But... even without a physical body, I still feel as though I am racing forward.
"There is no end to that."
A... voice?
"No. I should say there is an end. But for someone like you, it may take a very, very long time of self-perception before you experience what ordinary people would call a single second. Though you will die immediately after that second."
Is that so...?
But.
It is so free.
"Continuing onward into endless thought is not impossible. But before that, is there not someone waiting behind you?"
"..."
Oh, right.
That person.
Sheeta.
'I will give you a chance.'
A chance?
'Yes. A chance. A chance for you, a believer walking this stony road.'
'Go and find it. Seize what you want. Then I will not have to take back the Spiritwork Cradle by force.'
'As for the deadline... let us make it your entire lifetime.'
'I will wait for you for your entire life without doing a thing. If you catch it, I will take the "it" that does not contain it. If you die without finding the answer, then I will take the "it" that contains it.'
'Hah... That was somewhat of a monologue, was it not? But this is the only recognition and respect I can grant you. It is certainly not mercy.'
"It seems I do not need to make you turn around. Someone has already forced you to leave this place."
The voice was fading away.
The speed of that dash was suddenly slowing as well.
It was as if they might vanish from this place at any moment.
"Good luck."
Vaguely, he could hear human emotion in that voice.
"Satoru, huh... That takes me back."
After that.
Everything went black.
...
"Gameplay completed."
"Repeat: Gameplay completed-"
In shops, in the Labyrinth Tower, on the streets, everywhere, in every corner, that announcement echoed in a synthetic female voice.
It was not only the players who looked up in confusion.
Even the soulless NPCs seemed to raise their heads together, gazing up at the endless blue sky.
In Yerika Village, a mother watching over Akasa's sickbed, trapped in the cycle of illness and healing, gently stroked her daughter's head.
By the lakeside on the Third Floor, a Dark Elf stood beside a gravestone, wearing a faint smile of remembrance.
Deep inside the Black Iron Palace, a man thrusting a rapier into an empty prison cell and a man in a raincoat leaning against a great tree in the Labyrinth Tower both let out sinister grins.
The bread in Argo's hand fell to the ground as she blankly looked up with the players and NPCs around her.
For some reason, tears welled in her eyes.