In a hidden laboratory somewhere, there were no windows, and the entrance was sealed tight. The only sound was the steady, rhythmic hum of machinery in operation. The only light came from the faint, multicolored glow of indicator lamps blinking across all kinds of instruments.
In the darkness, those flickering colors looked like the eyes of demons opening and closing.
The space had been sealed away for a long time, untouched by the sunlight outside. The air inside was cold, dry, and lifeless.
There was no trace of vitality here. Not even from the withered, gaunt researcher lying flat on the pale bed. His malnourished, bloodless face made him look like a sleeping corpse. The only thing that seemed out of place in this cold room was the expressionless woman sitting beside him.
Ear-length short hair. A spotless white lab coat. She said nothing, keeping watch like a sculpture beside the silent man. The radiance she once had—her intelligence, her composure, her poise—had long since dissolved into the darkness of this place.
She did not know when he would choose to wake, or how long he would remain conscious once he did.
All she could do was replace the glucose drip when it ran dry, or brew him a cup of bitter, hot coffee after he opened his eyes.
Voltaire was the first to suggest that the universe began with the Big Bang. Paul would probably agree with that. Goethe was the first to believe that spiral nebulae were matter revolving around clusters of stars—what humanity now called galaxies. It was interesting. New scientific concepts were often first imagined through art.
Romantic people were usually better at imagining things, then reaching out to capture what they had imagined. And people like that were often the most skilled at obsession.
The kindness of science lay in its ability to benefit others, but scholars who carried such lofty ideals sometimes failed to keep pace with explorers as childish as children.
A castle in the sky, born from fantasy and freed from its chains.
But the price of admiring its beauty was the freedom and lives of ten thousand people.
It felt as if that was simply how things were meant to be.
And yet, there was no way to laugh.
The woman had no sense of time here. She could not see the sun rise or set outside. Although she had not been imprisoned in another world, she sat here as Aincrad's ten-thousand-and-first prisoner. Ironically, she possessed the key to open the prison. As a prisoner, she watched over the jailer here.
Or perhaps the creator god.
This man was nothing more than a single-minded scholar. He did not understand life, nor did he savor it. His wardrobe was filled only with fitted white shirts and unchanging black ties, along with more than a dozen standard white lab coats.
He had spent half his life on research, and because of that, he had sacrificed everything else a person ought to have.
He was not strong. He was anemic, and he got through his days by relying on energy drinks. Now that he had gone so long without proper rest, even a child of a few years old could shove him and make him stagger.
Let alone something as easy as killing him.
In the lightless laboratory, the woman spent her days thinking about this man, struggling with whether she should kill him.
Ding, ding.
The machine let out a soft notification tone. It was the signal that he had logged out voluntarily, that his consciousness had returned. For the first time, the woman's expression changed. No matter what she had been thinking before, her first movement was to take the man's bony hand.
The man's breathing shifted from steady to slightly rapid. His eyelids trembled in their sunken sockets, then slowly opened a few seconds later, revealing black eyes no different from the darkness around them. His calm gaze held none of the confusion of someone waking from sleep.
He had not truly been asleep to begin with.
He had merely been active in another world.
But switching from an unmatched virtual body back into this frail flesh was not something he could immediately adapt to.
His dry lips parted into a narrow slit, and he looked straight at the woman beside him.
"Rinko."
He spoke her name. That was all.
The meaning contained in those two syllables was probably not gratitude for her care, but the cold reasoning of a researcher: wondering why she had not left, or perhaps why she had not ended him.
Rinko Koujiro carefully helped him sit up. Once he was half-seated, the man began pulling at the electrodes on his hand and the IV needle connected to the drip. After that, she left his side and walked a short distance away to prepare a cup of coffee.
He always consumed only the bare minimum before impatiently connecting himself back to that place.
He had long since stopped valuing his life on this side, hadn't he?
"Curry. Do we have any?"
Kayaba Akihiko left the bed on trembling legs, felt his way step by step to the computer, sat down absentmindedly, and spoke in a flat voice.
Rinko, who had been preparing the cup, froze and looked at him in surprise.
"Is there none left? Was the instant food we prepared in advance not enough?" Kayaba assumed it had simply run out.
"No… there is still some," Rinko said hurriedly.
"Make one."
"What flavor would you like…?" she asked carefully.
"Anything."
After that, Kayaba's entire attention gathered on the computer screen. His gaunt fingers began to move, seemingly browsing through some kind of data.
Rinko quietly tore open the package of instant food. While waiting for it to heat, she still poured a cup of rich black coffee and placed it beside the mouse Kayaba was moving lightly.
The snow-white glow of the computer shone on his face, making him look even more like a ghoul that had crawled out of a coffin. Rinko watched him, wrapped her arms lightly around herself, and turned her head away.
"Today… have you finally decided to rest?"
"No." Kayaba's mechanical reply was as familiar as ever, just like when they had worked together at the research institute. Without any awkwardness, he picked up the coffee and took a sip. Only that movement still carried a trace of the man he had once been. "There is simply some data I need to integrate and observe again."
"You said Sword Art Online was already complete from the very beginning."
"But the people inside it are not perfect."
"Didn't you… only want to observe Aincrad?"
"Of course. But that does not conflict with my interest in them."
"Them? Who…?"
Kayaba stopped moving. A few seconds later, he turned the computer screen toward Rinko.
"Fluctlight?"
Rinko read the word aloud, not understanding.
"Fluctlight," Kayaba murmured. "The human soul."
"The soul. Does something like that really exist?"
"Whether in religion or science, there are many interpretations of it. Personally, I see it as a record. Humans interfere with the outside world through the body and govern themselves through the mind. They accumulate information, evolve emotion, integrate thought, and gather it all in the brain as a record. The crystallization of that record is the soul."
"Most scholars believe consciousness and the soul may simply be integrated functions of the brain. Unlike Christof, a professor of Computation and Neural Systems at the California Institute of Technology in America, who believed the human soul was produced only by specific cells in the brain, though his experiments with Crick are famous."
Kayaba spoke softly.
"Inside the brain cells of the human body are countless microtubules, and within them are countless photons. What exists there is the summary of a person's life. If one reads that quantum field, one can obtain all of that person's data. Calling that the soul is perfectly acceptable."
"I understand. I do understand." Rinko looked at him. "But why have you suddenly become interested in this again?"
Kayaba smiled quietly.
"Because this is the very source of the swordsmen's strength in that floating castle."
He picked up the coffee again.
"Aincrad. The endpoint of my ideal. What makes it so fascinating, aside from its vast foundation, is its residents. A fantasy world cannot lack the people living in it. Otherwise, it would only be a floating dead city."
He said this without the slightest self-awareness.
"For that reason, I developed several AI templates to serve as the NPCs active inside it. Most of them act as shop owners, quest handoff characters, and so on."
"And finally… for command-type AIs capable of handling more complex work, I programmed them and gave them the ability to learn. This is no different from human growth. They follow the same journey: from babbling ignorance, to abundant knowledge, to shaping the world within their hearts, and finally coming alive within the world."
He spoke of all this as if it were nothing, but Rinko was already stunned.
"Perfect autonomous artificial intelligence?" she asked, somewhat shaken.
"Not perfect. Merely top-tier."
Rinko could not speak.
If that was true, then the AI he had created to accompany the floating castle was an even more astonishing treasure than Sword Art Online itself.
"The Law of Accelerating Returns," she said, a little stiffly. "In a more advanced society, the capacity to keep advancing is stronger, and the pace of development is faster. That is one of the standards by which a society is considered advanced. People in the nineteenth century knew far more than people in the fifteenth century, so naturally, the nineteenth century developed faster than the fifteenth."
"Yes. That is why even if I accomplish something like this, it is not particularly strange. I am standing on the work of many others," Kayaba said.
The concept of artificial intelligence was extremely broad, so it could also be divided into many types.
Weak artificial intelligence referred to AI that excelled in a single field, such as an entity capable of defeating a chess champion. But it could only play chess. If you asked it how to store data more efficiently on a hard drive, it would not be able to answer.
Strong artificial intelligence referred to human-level AI, one that could stand equal to humans in every respect. Any mental task a human could handle, it could take on as well. Creating it was far more difficult than creating weak AI, to the point that it might not even be possible.
"Professor Linda Gottfredson… defines intelligence as a broad mental ability that involves reasoning, planning, solving problems, thinking abstractly, understanding complex ideas, learning quickly, and learning from experience," Rinko said with difficulty. "In all of those areas, it is undoubtedly no different from a human. It handles them with ease."
"And lastly, Artificial Superintelligence," Kayaba Akihiko said, picking up her train of thought perfectly. "Superintelligence. Professor Nick Bostrom defines it as an intellect far smarter than the best human brains in practically every field, whether in scientific creativity or social skills. It may be only slightly stronger than humans, or it may surpass them by hundreds of millions of times across the board."
"At the beginning, they had nothing. They simply started learning from scratch."
"But what about cognition? Even now, computers capable of instantly calculating thousand-digit multiplication can be found in any household, but how could one understand a picture casually scribbled by a toddler?"
"I don't know either."
Kayaba Akihiko remained unmoved and brushed her off with that answer.
With those irresponsible words, he answered the grand feat of creating a god.
Tens of millions of years of human history. The thoughts of countless great figures. All of it could be poured into that single AI. It could swallow the boundless river of humanity whole, and even its upper limit could not be predicted.
A human with an IQ of 130 could be called smart, and one with an IQ of 85 could be called dull, but no one could describe an existence with an IQ in the tens of thousands.
Such a concept had never existed.
Humanity's rule over Earth could be reduced to two words:
Intelligence.
Imagination was only its companion. Humans could not imagine what they did not know. If they had never seen beyond the darkness, they would never know what lay on the other side. However vast their imagination might be, it could never touch even the smallest fragment of the unknown.
But if such a being possessed knowledge as vast as a galaxy and an intellect beyond any written record, what kind of threshold could it reach?
Human aging.
Incurable disease.
World famine.
War.
Expansion beyond Earth.
Manipulation of celestial phenomena.
Miracles that seemed utterly impossible might take it only a few seconds to solve.
An omnipotent God descending upon the world.
"And the only thing we need to worry about is whether that God is merciful?"
Rinko's voice came out dry.
And this man treated a nascent god as mere scenery for that floating castle?
"To truly reach the realm of divine thought, they are still far from enough. Because right now, they really are just like us humans… like the countless living beings of this world."
"Perhaps… I do not even think of them as intelligent. Maybe all I did was simply program humanity itself."
"Stop joking…!" For the first time since coming here, Rinko raised her voice.
"I'm not joking. We humans are the same." Kayaba looked at her. "Rinko, have you ever witnessed the possibilities of humanity?"
"What…?"
"I am not talking about the kind of possibility where the body bursts with tremendous strength in a crisis. I mean thought alone. The possibility of thought spreading to some distant, immeasurable place. I freed the bodies of these ten thousand people from their shackles, and in the end, their unbound souls finally began to spread their wings, one after another."
Kayaba smiled.
"That is what I find truly irresistible. Compared to The Seed, their existence gives Aincrad far greater radiance."
Rinko stared at him, stunned.
"You don't understand?" Kayaba kept smiling. "It is the same. Merely the same way of understanding AI. The human brain itself is the most complex product. No one knows its potential, let alone the soul, a concept that remains vague even now. I have always believed that a soul transformed into a butterfly can approach a perfect AI."
"Especially after witnessing the transformation of those two."
"But… how can the functions of the human brain compare to machinery?"
"Perhaps they cannot. But did I not already say it? I freed them from their shackles. The shackles of the bodies they were born with, the bodies that imprison them for their entire lives."
"…"
"The brain is fragile, just like the method of imprisonment I use: a helmet capable of burning them to death. But what about the soul…? A soul that thinks, grows angry, roars, and screams like a cornered beast fighting for its life?"
"Does it have an upper limit?"
"Can time dilation be applied to the soul? The body cannot withstand impossible speed, but what about the elusive soul?"
"Without limbs too slow to react, without a weak body to drag it down, the exposed soul charges forward at will. Calculation, cognition, prediction—all of it would rise hundreds or thousands of times over. Even if only for a moment, that alone would be an extraordinary result."
"To reach infinity… to reach that threshold, to reach the Fluctlight."
Kayaba Akihiko let out a long breath.
"Rinko, this is the greatest surprise Aincrad has given me."
"Natural humans and manufactured gods. The bond between the realms of humans and gods."
Rinko could not say a single word. She could only stare at Kayaba, who was completely immersed in it.
He really was insane.
But he was also a genius through and through.
"But there are still questions." Kayaba went on talking to himself. "Why is it that fully autonomous intelligence, which should be growing like humans, shows no remarkable mutation at all, while humans who were originally ordinary to the extreme, people with no prior foundation whatsoever, suddenly look down upon this data world through the eyes of Fluctlight?"
At last, he spoke the next line with a romanticism fitting for a fantasy world.
"Could there truly be a god high above… pulling at the threads of their fate?"
Rinko still could not let it go.
He clearly possessed such talent.
Yet he remained obsessed with the floating castle in his heart.
He was so simple.
So innocent.
And yet he had abandoned morality and humanity.
"The recording is complete. I'm going back," Kayaba said, then stood up.
"Cu-curry…"
"I won't eat it. Next time, perhaps." The obsessive scholar walked toward the bed.
"Next time…?"
"Yes… the next time I wake up, Rinko."
Kayaba spoke in his usual tone, attached the electrode pads to his body again, and closed his eyes impatiently, entering the world he believed to be one where humans and gods stood without distance between them.
Rinko silently watched him and listened as his breathing gradually became even.
She walked to the computer and scrolled the wheel.
"First Awakened Adapter: Life-Farewell Halberd, Didos, Makoto Kaizuka."
"Second Awakened Adapter: Infinite Sword, Yurnero, Satoru Suzuki."
"Third Adapter: Assassination, PoH, Vassago."
"Fourth Adapter: Dual Blades, Kirito, Kazuto Kirigaya."
…
A sorrowful expression appeared on her face.
Behind her, the kettle began to bubble, giving off the sound of boiling water.
The curry was almost ready.
Two servings.
Only she would eat them.
Alone with the darkness.