[Seiji's POV]
It was almost impossible to imitate the frequency of living beings. There were things like heartbeat, breathing patterns, muscle twitch, organ movement, nerve firing, cellular activities and even blood flowing.
This made living beings have chaotic vibrations that changed a thousand times every fraction of a second. It was almost impossible to tune my sword to match that frequency.
But demons were different. They were not quite living beings even though they were not dead either.
I spent months trying to figure out what their rhythm was. It was complex but I was able to find it in the end.
I called it the Demon's Key, and every demon shared this frequency.
Demons were almost perfect beings except for their fatal weakness to sunlight and wisteria. But being perfect means being static and unchanging, and the demons were just that. They were not like other living beings who were completely chaotic and unpredictable.
Not only that, all demons without exception came from Muzan's blood, so they shared the same frequency. Once I figured out the Demon's Key, it worked for every demon I encountered.
It didn't matter how armoured they were, it didn't matter if they blocked it perfectly. Any blade I wielded became a weakness to them.
The only thing they could do was dodge and run.
"You were more complex than any demon I've encountered, but you still shared the same Demon's Key," I said while turning towards him.
Kokushibo remained in his place, absolutely stunned at his state. He did not even heal himself and just remained half-armed and half-faced.
How long had it been since he was actually cut?
"How is that possible?"
Kokushibo asked while turning back. His face was cut in half diagonally, and his three remaining eyes looked at me like I was a being more supernatural than he was.
"Commitment, focus and sheer will," I joked, "I'm kidding, I just hate you that much."
There was no amusement in his eyes. For the first time since I met him, I read emotions in his eyes. He was no longer that living weapon devoid of humanity. I saw wonder, anger, excitement, and caution.
'Let's put fear in there,' I thought to myself and brought my sword up.
The grip I had on my sword changed like swaying water while my muscles tensed and relaxed rapidly, all so that I could maintain the vibration of my sword.
As a result, my sword released an eerie sound that I could not hear. But it must be lethal because I saw blood coming out of Kokushibo's ears.
The frequency was the bane of demons. It was a literal song of death for them.
I shot towards him like a bullet. Obviously not fast enough, considering he had enough time to heal his body and meet me with a perfect form.
But for onlookers, it was an instant. We were so fast that most people could not tell our slowest speed from the fastest. They were all quick enough to escape the naked eye.
Kokushibo exhausted all his techniques in trying to block my attack. But even the most simple swing of my blade cut through everything like butter.
Just like that, centuries of practising defensive sword skills went to waste. All blocks, or parries, were equally pointless in front of my blade. The battle shifted. It was no longer a clash between two swordsmen.
In Minecraft terms, it was a clash between a pro and a hacker. An attack that could not be blocked was so outrageous, especially when both of us were nearly equal in skills.
But I didn't feel an ounce of guilt. Demons had been abusing their inexhaustible stamina and regeneration since forever. This was just a taste of their own medicine.
It took losing his limbs six times and being cut in half eight times until Kokushibo started running.
"Isn't that cowardly?" I mocked and ran after him through the forest.
He was fast but not faster than me, so he still got sliced up here and there as he ran. If my sword was a Nichirin blade, he would've been in big trouble. Lucky for him, it was just a very well-made sword.
He ran, but as he ran, his mind worked to come up with a strategy. When he finally got an idea, he stopped.
He landed horizontally on a big tree trunk and bounced back with incredible force. The tree shattered into splinters from the force.
He attacked me.
The best defence was offence, that was the theory behind his new strategy.
His plan was so utterly predictable that I laughed out loud. He couldn't look at me while running, so I had been the sole abuser of our overpowered eyes.
His sword sliced through the air and came at my torso. I twisted my body in a heartbeat and easily moved above his swing. On the other hand, my sword sailed past all defence and chopped off the upper portion of his head.
Our bodies passed each other like flashes of light, and I was unharmed while he lost four eyes and a forehead.
I bounced back on a tree like he did, but my action barely shook the tree. I did not have raw power like he did so I couldn't waste momentum, leading to more graceful actions.
Kokushibo was in mid-air when my sword weaved multiple slashes towards him. But this time, my attack was blocked...
!!!!
...by a branch of a random tree, which Kokushibo cut off with his last attack.
"That's a dangerous technique you've invented, but like all else, it has a weakness," Kokushibo said as we remained suspended in the air.
I smiled. Indeed, the weakness of this technique was that once my sword was tuned to cut one thing, it cut other objects worse than a normal sword.
I could change the vibration of my sword and match it to another object like steel rather quickly but not fast enough to do so in the middle of a battle of this calibre.
"Smart," I commented, and then the fight ensued again. This time, it was not one-sided like previously.
We exchanged attacks once more; this time, Kokushibo used different objects on the ground to block my attacks. Sometimes he would use wood he cut from a tree, other times he would kick up a rock and use it as the point of our clash.
That revealed to me once more how different Kokushibo was compared to other demons. To adapt as easily as that was human nature. It was Demon Slayer's nature to be exact.
He took a few seconds to adjust his fighting style, and then he was comfortable enough to go full power once more.
"Moon Breathing: Fourteenth Form,"
I jumped back as far as I could and landed with a ready stance.
This time, I finally used the power I created during this one year.
My legacy.
I've imagined this many times before in the past. It was always my plan to create my own Breathing Style after I learned every other style. I thought it would be the combination of every existing Breathing Styles, and that it would be the perfect Breathing Style.
It's funny how things turned out in the end. Instead of a perfect technique, I had to come up with something completely new, different from everyone's expectations including my own.
I thought my masterpiece would be called something cool, like Sky Breathing, Star Breathing, Eclipse Breathing and maybe even Space Breathing. Something that would strike at the hearts of anyone who heard it.
But in the end, it turned out to be much simpler and raw. The name would only strike at the hearts of those I hate the most.
...
"Demon Slaying Arts: First Method,"
Kokushibo exploded first. The forest yielded under the brutality of his technique. His sword slashes expanded as they flew outwards, growing bigger than the tallest trees in the forest.
There were slashes inside his slashes. Tiny moon blades acted as the blades of grinders as they tore through anything and everything. The organic and non-organic all died under his demonic power.
"Catastrophe, Tenman Crescent Moon"
...
When the attack reached halfway, I shot forward at my fastest speed. I outran sound and reason.
Demon Slaying Arts was like the Bible in the sense that it was a compilation of everything I've learned in my life, made into one style.
I selected the most malicious and lethal demon-killing techniques I know to create one ultimate form.
And at its core was a new type of power fate never planned to create.
The world was not ready for the power I've brought to life.
"Frequency of Death,"
I moved at the speed of Thunder Wind Breathing. I shot forward in a straight line like Thunderclap and Flash. In my hand was a blade that hummed a tune of death.
The vibration was subtly different from the previous one. It sang a melody that could kill a demon. It became a sword that was more lethal than a Nichrin blade.
A technique worthy of its name.
...
...
[IMAGE]
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