The first thing that changed was the sense of distance. The world seemed as though it had become curved. Suddenly, this periphery, space itself crumpled. He merely unleashed his Intrinsic Demon Art, yet the aftermath alone was damaging the world.
"Listen well. This is my own form of respect shown to one standing at an extreme of foolishness."
Demon King. Academia.
Even within the distortion of space, he stood arrogantly and continued his explanation.
"Even a fool like you must know that planets orbit around the center of the sun, right? I'll assume you believe that. Because if I have to explain from there, there's no answer.
A planet's orbital speed is approximately 30 km per second. 87 times faster than the speed of sound. Considering that the sword tip of a Qigong Master who can fly and leap barely exceeds the speed of sound, movement within this land is truly insignificant."
There would be no need to explain. Unless it was someone like the Blue Tower Lord or me, the Sword Saint was a Qigong Master who had devoted his entire life to the sword. He wouldn't know magical studies.
Nevertheless, the Demon King continued his explanation.
To share the wonder he had felt.
"However, the speed of light is 300,000 km per second. It reaches ten thousand times that distant speed."
Light flashed in the Demon King's mind. A speed at which 'seeing' cannot be established. He knew he had reached it only after it had passed by. It could never be measured by conventional means, but the Demon King, full of curiosity, eventually found a way to measure that speed.
"Now. Then, think about it. We are navigating this universe at 30 km per second. So then, the light shot from here would be 30 km faster than the speed of light. Just as swinging a sword on a running carriage makes it that much faster. If you think about it intuitively, wouldn't that be the case?"
The Demon King's explanation was easy for even a layman to understand, and the Sword Saint also roughly grasped it. The Demon King nodded and continued his explanation.
"It was a 1/10,000th margin of error, but I created a precise speed measurement device that could distinguish that much. It utilized the interference properties of light, but since you wouldn't be able to understand it, I'll omit the detailed explanation. Anyway, so I measured how much the speed of light would differ. And do you know what result came out?"
A thought that anyone could have come up with. But an experiment that no one could carry out due to various limitations. The Demon King was the first to succeed, and discovered the most fatal secret of great nature.
"It was the same."
Invariance.
The Demon King recalled the shudder and wonder he had felt at that time. At first he couldn't understand, wondered if the device was broken, and struggled to find what was lacking. But the truth always repeated the same answer.
"Always, at any time. The speed of light was the same. It was invariant, absolute. That value was always the same! Truth betrayed intuition!"
The Demon King, filled with ecstasy, spread both arms wide.
"The truth is, it lies beyond our perception and intuition. It doesn't matter if you can't believe it, if you can't understand it. There was only one conclusion. The speed of light is absolute!"
The Sword Saint had only been listening to the Demon King's story. It wasn't that he concentrated on the Demon King's lecture. It was because the unknown rules surrounding the space were binding him.
'Slow. Everything is.'
The Sword Saint concentrated his consciousness on his body and sword and spoke.
"What meaning does that have?"
The Sword Saint spat out a sentiment that a layman might make. The Demon King, filled with rapture, felt that great temperature difference and rapidly calmed down.
"That is the reason you cannot win. If the speed of light is invariant, all the physical quantities we defined change. Distance, mass, even time. They change form to match that truth."
It was a realm the Sword Saint could not understand. No, was it only the Sword Saint? Even intellectuals, magicians, and scholars who were considered the best would take a long time to bring this truth into the realm of understanding. Even I, who have mind-reading abilities, my reading speed can't keep up with understanding.
"I could tell you how it changes... but you wouldn't understand even if you heard it. Then learn it with your body. Just as you've always done."
The Demon King looked at the Sword Saint as if pitying him and unleashed his Intrinsic Demon Art.
"Light is too fast, so I'll change it only to the extent you can understand. Now, receive this."
Absolute Speed Control.
Subsonic.
The body slows down as if soaked in water. At the same time, the entire world stretches out far in a straight line. Wind, sound, everything becomes viscous, and the sky turns pitch black so nothing can be seen. We hadn't moved a single step, but the world swelled like foam, creating a distant void space.
I had thought the Demon King's ability was heterogeneous, but his magic wasn't spatial magic.
'Speed'. And not just any speed, but controlling the speed of light, which is the limit speed of the world.
What he was shrouded in wasn't space. It was a region where speed was extremely limited, which merely had the effect of expanding space.
The Intrinsic Demon Art crushes existence. If one had Qigong or an Intrinsic Demon Art and could protect the body with one's own rules, they could at least endure. In this heterogeneous space, enduring was the best one could do. Even the Blue Tower Lord and Shade were barely alive.
The same was true for the Sword Saint.
"---."
'A power that makes me slow? Thread Slash.'
Even in the midst of that, he squeezed out the Principle and slashed. Slowly but surely, the sword moved and slashed the domain surrounding the Sword Saint.
But nothing happened. For the first time, bewilderment was felt from the Sword Saint.
'First time... experiencing this. A strange sensation. Beyond being heterogeneous.'
He didn't know.
Even the Sword Saint who held the Principle in his hands couldn't even get a sense of this Intrinsic Demon Art. It was a realm that couldn't be understood by intuition. It had departed from the track of common sense.
"I've taught you everything. Try to overcome it. Absolute Speed Bullet. The fastest object in this world."
Amidst all this, only the Demon King's voice was heard clearly.
A space where everything became distantly slow. Within it, a sphere approaching absolute speed flew in. Fast enough to stand out alone, overflowing with dangerous presence.
The Sword Saint tried to move. But no matter how much force he applied and swung his sword, the speed couldn't keep up.
'Interval Slash... No. There's no response.'
What changed wasn't weight. The rule of absolute speed. Since a limit was defined, the sword speed couldn't keep up with it. The more force he applied to increase speed, the heavier the tip of the sword became.
'Vertical Slash... It's not a direction problem either. What in the world is this world?'
Even with the Principle, one cannot twist the world to one's will. One must decide what one is slashing, what image one is going to manifest.
But in a world where common sense had collapsed, the Sword Saint couldn't get his bearings. If one were to say he couldn't understand because he was a fool who only trained his body, that would be too harsh. Even an ordinary person wouldn't be able to understand.
'As expected. Worthy of calling himself the Demon King.'
It couldn't be helped. The Sword Saint decided to admit defeat for now. Instead of overcoming this world, he focused solely on himself.
'Middle Stance Slash.'
The Sword Saint took the middle stance.
The Principle of returning to the middle stance regardless of any situation, any posture. Returning to the posture that is first engraved in the body when learning swordsmanship, he slightly shook the tip of his sword.
'Center Slash.'
The vibration gradually grew. The swaying tip of the sword bisected the Absolute Speed Bullet.
It was enormously powerful and heavy, but that didn't matter. The Sword Saint's sword perfectly split the center of the bullet. The Absolute Speed Bullet split in two and grazed past the Sword Saint. A moment later, a massive explosion rose slowly compared to its scale.
"Hmm?"
The Demon King tilted his head.
"Strange. That's a bullet that can't be slashed with such a structure. Can a Qigong Master who has reached the Principle force that much?"
It wasn't a situation he couldn't understand. Even if the Demon King's Intrinsic Demon Art was mysterious and powerful, it was still an Intrinsic Demon Art. While it could overlap with other Intrinsic Demon Arts, it couldn't ignore them. The Principle would be similar.
Shaking his head, the Demon King fired dozens of Absolute Speed Bullets.
"Let's see how long you can keep this up."
The Sword Saint glared and began to slash all the flying Absolute Speed Bullets.
Within the Demon King's Intrinsic Demon Art, there was a limit to speed. Slashing dozens of Absolute Speed Bullets at that slow speed was indeed worthy of admiration for the Sword Saint. But soon he reached his limit.
Before he could even return to the middle stance, one Absolute Speed Bullet approached his side. No matter what, it was too late. The tip of the sword headed to block the Absolute Speed Bullet with a considerable delay, but within the limit speed, it had reached an impossible realm.
But.
It was slashed.
Even though the sword hadn't arrived yet, the Demon King's Absolute Speed Bullet split in two.
"Hmm?"
While the Demon King was dumbfounded, the Sword Saint still swung his slow sword. It was an afterthought. The Absolute Speed Bullet had already been slashed, but he belatedly moved his sword. And when he placed his sword in the empty space, the blade vibrated with a *ting*.
Only then, we could all understand.
"...Hah, really. It's absurd."
The sword hadn't arrived, yet it had already slashed the bullet. And the Sword Saint swung his sword as if to repay that. It wasn't that he swung the sword and therefore it was slashed. It was slashed, therefore he swung the sword.
Cause and effect had been reversed.
"He fixed the result of slashing."
"A slash in advance."
"It's no longer the realm of Qigong or magic, is it."
Now even the Demon King was bewildered. The opponent's realm had far exceeded prediction.
The pinnacle of Qigong.
The pinnacle of magic.
The two were completely different. They would never be able to understand each other. But, in a sense, because they were exact opposites, they were similar.
Interest appeared in the Demon King's eyes. Just how far the Principle could overcome, his eyes sparkled with curiosity.
"Absolute Speed Control. Photon Impact."
"Keep slashing."
Countless lights flashed. Light forged in a world where absolute speed was restricted. It was a phenomenon close to the materialization of light. The Demon King alone even reproduced the White Tower Lord's Intrinsic Demon Art.
Facing that overwhelming destruction, the Sword Saint took up his sword. After swinging through the empty air a couple of times to check the sword's speed, he steadied his stance and prepared to slash the Demon King's attack.
While the two fought a heaven-shaking battle, I, who had desperately fled even in the slowed state, barely escaped from the Demon King's Intrinsic Demon Art.