"A Crimson Blade, you ask? I simply gripped the hilt, and the sword turned red, Elder Brother."
.....
Good grief, Yoriichi...
Of course, I hadn't allowed myself even a shred of expectation.
The visions of causality told me that the Yoriichi of the original timeline had joined the Demon Slayer Corps before me and taught the Breathing Styles... but looking at his current social ineptitude, I have no idea how he managed to communicate with anyone back then.
Could it be... I know Rengoku is a different case, but surely everyone else didn't actually hate him for being so obtuse, did they...?
***
It has already been half a month since Yoriichi's wedding.
Nearly a month has passed since I placed the order for Yoriichi's Nichirin Blade and handed over my own shattered sword for repairs.
I understood that his sword would take priority since I requested it so, but by now, my repaired blade should have arrived....
'I'm sorry! Young Tsugikuni! Materials have run dry, so work started late. It's going to take a bit longAh!'
Looking at the report delivered by Niimiya's Kasugai Crow, it seemed it would still be a while before the work was finished.
In the end, I had to temporarily withdraw from the front lines. The Master of the Mansion told me that since I had just recently eliminated an Upper Rank Demon, I was permitted to rest a while longer.
Meanwhile, good news arrived: within those fifteen days, another Hashira had manifested the Slayer Mark. It was the Wind Hashira, Shimotsuki Shusui.
He claimed it appeared during a desperate struggle against a Demon. Immediately after the manifestation, he challenged Minase Hiyori to a rematch, but since Minase also manifested her Mark, the result of their duel remained unchanged.
What weighed more heavily on my mind was that Shimotsuki's Mark, like Amano's and Minase's, was not permanent. Unlike Yoriichi and myself, these Mark-bearers only showed the mark when entering combat. Under normal circumstances, it vanished from their skin.
This didn't mean their lifespans were any safer. According to Yoriichi, while their bodies experience no physiological change when the Mark is hidden, Amano, Minase, and Shimotsuki are all living on borrowed time, just like me.
This implies that once the Mark is manifested—whether it remains permanently or only during battle—one's lifespan is destined to be cut short. I still cannot fathom why only Yoriichi and I possess permanent Marks.
Could it be related to the lineage of the Tsugikuni...?
And then.... the Transparent World is also an issue.
Currently, it is a realm reached only by Yoriichi and myself.
Unlike the Mark, which grants extreme precision and physical enhancement at the cost of one's life, the Transparent World heightens all senses to their ultimate peak. It allows one to see through the internal structure of the body, predict the opponent's movements, and execute perfect, refined techniques—all without any known side effects.
However, I cannot say one is superior to the other. Their utilities differ. Even with the raw power and breathing efficiency of the Mark, it is useless if you cannot land a hit; conversely, predicting movement is futile if the body lacks the speed to act upon that foresight.
Since the Transparent World carries no risk to one's life, I'd like to declare it the superior trait, but the problem lies in the difficulty of attaining it. Compared to the Mark, which is relatively easier to trigger, I have no clue how one intentionally reaches this state.
I'll set aside Yoriichi, that natural monster who was born into the Transparent World. In my case, I reached it simply because I was on the verge of death. I have no practical advice to offer others.
If more Demon Slayers could reach the Transparent World, killing Kibutsuji Muzan would be a simple task.
Sigh. What am I to do?
"Don't you agree, Shimotsuki?"
I asked, looking down at Shimotsuki, who was sprawled face-down on the ground.
This man... despite being trashed by Minase, he came to me to request a duel, and his current state was the inevitable result.
"Can you even hear me anymore?"
Shimotsuki Shusui, the Wind Hashira. You truly are a blockhead.
You likely have no idea that I didn't even include you in the list of the 'Five Special War Potentials.'
I sighed and was about to give his cheek a light slap to wake him up.
"So this is where you were! Young Michikatsu! I see Lord Shimotsuki is here as well!"
A thunderous voice echoed across the training grounds. In the entire Demon Slayer Corps, there was only one man with such boundless, high-spirited energy.
"Ah, Lord Rengoku."
"Hahaha! Haven't I told you that you may speak to me casually!"
Rengoku Tenjuro approached with his characteristic, boisterous laughter.
"But, you are my elder...."
"Then what about Shimotsuki?"
Rengoku spoke while looking down at the silent, prone Shimotsuki.
"The defeated have no right to speak."
Since he told me I could speak casually if I won our first duel, I've been doing so. And just now, he was utterly crushed again.
"Regardless, what brings you here? Has an emergency occurred?"
"Young Michikatsu! Would you care to spar with me?"
Suddenly?
***
After dragging Shimotsuki out of the way, Rengoku and I stood facing each other, wooden swords in hand.
It wasn't as if this was my first time sparring with Rengoku.
Aside from Amano, who was my Tsuguko and with whom I frequently exchanged techniques, it had been nearly a year and a half since I last sparred with another Hashira due to our busy schedules. However, I had crossed blades with every Hashira at least once, excluding the physically ailing Master Banda.
Among them, Rengoku stood out; unlike Shimotsuki, our duel had ended in a draw because our wooden swords snapped at the exact same moment.
But the situation now was different. I had attained both the Slayer Mark and the Transparent World, while Rengoku had yet to reach either.
"This will be quite difficult for you, Lord Rengoku."
At my words, Rengoku laughed heartily and—
"Haaaaaaaa—!!!!"
Fwoosh—!
With a mighty shout, flame-patterned Marks manifested on both of his cheeks.
"The Mark has already been manifested!"
I stared at him, flabbergasted. Is manifesting a Mark supposed to be like transforming into some legendary warrior from a folk tale?
Rengoku settled into his stance, ignoring my bewilderment.
"As your senior who saw you into the Corps, I cannot afford to lag behind forever! I shall take a lesson from you!"
Hmph—!
Flame Breathing
First Form: Unknowing Fire—!!!!
Rengoku charged forward with the momentum of an erupting blaze.
Multiple mirages of flame flickered and converged into a single, devastating horizontal slash.
Hoh.
Moon Breathing
First Form: Dark Moon, Evening Palace
I countered with a horizontal slash of my own.
Flame Breathing is characterized by its aggressive, disciplined nature. It involves many wide, powerful slashing motions and sudden dashes.
Its strength lies in the power of a single strike. In terms of pure cutting power, it is superior to almost any other style. Even my Moon Breathing, Eighth Form: 'Piercing Moon Crescent,' was developed by referencing the mechanics of Flame Breathing.
The drawback, however, is that the movements are discrete rather than continuous. Because every strike involves an explosive dash or a massive swing of the Nichirin Blade, a less-skilled practitioner can be left vulnerable to a Demon's counterattack in the gap between forms.
In other words, a gap appears when the strike ends.
Moon Breathing
Fifth Form: Moon Spirit Calamitous Eddy
Using this agile and swift technique, I unleashed a flurry of strikes over a wide area, aiming for the opening created by his finished move. Ordinarily, the match would end here.
However, my opponent was a Hashira—the man who stood at the absolute pinnacle of Flame Breathing. He would never simply allow such an obvious weakness to be exploited.
Flame Breathing
Fourth Form: Blooming Flame Undulation—!!!!
My wide-range slashes were swept away by a swirling vortex of flames centered around Rengoku.
Even though I had not yet activated the Transparent World, he was undeniably strong.
Moon Breathing
Flame Breathing
Rengoku and I prepared our next attacks simultaneously.
Fourth Form: Solar Eclipse
Sixth Form: Flowing Blade-like Flames—!!!!
Rengoku's blade, which carved through the air as if the flames themselves were flickering, collided with my sword, which traced a circular path as if to gouge out the moon from the sky.