[I hereby declare that Uchiha Sasuke is the perfect successor to Thunder Breathing—the next Thunder Hashira. After all, Sasuke is a pillar!
Wasn't there even a fan creation of Sasuke storming the Infinity Castle? Hahaha!
That scumbag boss really has too many enemies. There are just too many people who want him dead—from Sasuke to Ultraman, it's endless.
Didn't expect Sasuke to be this compatible with Thunder Breathing, but it makes sense. He already uses a Kusanagi Sword, so the sword forms of Thunder Breathing suit him perfectly.
It's definitely better than Agatsuma Zenitsu and Kaigaku—one can only use the First Form, and the other is so cowardly he couldn't even use the First Form at all.
Agatsuma Zenitsu: "Senpai, do you know how many points I dropped just to get matched with you?"
And Kaigaku… honestly, what a disgrace among the Upper Ranks. Did that scumbag boss not even bother with background checks when recruiting new hires?
Then again, think about it. Muzan's been alive for hundreds, maybe thousands of years. Either pretending to be a child or dressing as a woman to dance for powerful figures, all just to get them to help him find the Blue Spider Lily. But he probably never imagined that the flower blooms in broad daylight, where demons can't even go. Hahaha!
A final boss acting like this really is an embarrassment. Then again, he only acted bold once in his entire life, and got chopped into pieces by Yoriichi. One moment of bravery, a lifetime of paranoia, huh?]**
After washing up, Kaede Kitahara sat down and began writing in his diary as usual.
That entire day, he hadn't just been guiding Uchiha Sasuke—he had also been training Thunder Breathing himself. With his experience of maintaining the Eight Gates as a constant state, his progress far outpaced Sasuke's.
Inside the Uchiha compound, Sasuke's body trembled slightly.
He had used Lightning Release chakra far too many times today. While his progress in Thunder Breathing was impressive, the strain on his body was just as severe.
Unlike Kaede, he didn't have the Uzumaki Clan's Sage Body to support him. For now, all he could do was apply medicinal ointments to speed up his recovery.
Fortunately, when he had trained Chidori in the past, he had often suffered burns from lightning, so he had already prepared plenty of specialized medicine.
The moment he sensed the diary updating, he opened it immediately.
When he read the contents, he froze.
He hadn't expected Kaede to rate him so highly—to call him the best successor of Thunder Breathing.
Sasuke knew full well that his progress lagged far behind Kaede's. Being praised like this made him feel a little embarrassed.
Thunder Hashira…
He recalled that Kaede had briefly mentioned it earlier. In each generation, the strongest practitioner of a breathing style would be given the title of "Hashira."
They were the pinnacle of their respective styles.
Apparently, there were other breathing styles as well, but Kaede hadn't gone into detail, and Sasuke hadn't pressed him. He knew Kaede carried many secrets, and in his current position, asking too much might only push him away.
Now, Sasuke felt nothing but gratitude toward him.
He could also tell that Kaede was teasing him a little.
Sunny Sasuke is a pillar too, huh…
As for Agatsuma Zenitsu and Kaigaku… they must be other users of Thunder Breathing.
Sasuke had no idea where Kaede had learned this sword style from. What was clear, however, was that it came with a complete training system—one that could lead directly to Kage-level strength.
Compared to something like Kakashi's Chidori, this was far rarer. It was a true secret art.
"Thunder Breathing? What new trick is that kid up to now?"
Within the Senju Clan's territory, Tsunade, having just finished her training, frowned slightly as she read the diary.
But what truly shocked her was the mention of Muzan—this so-called "scumbag boss" who had lived for hundreds, even thousands of years.
What kind of terrifying ability was that?
Was he even human?
The last time Kaede had mentioned someone living that long, it had been the Otsutsuki Clan—whom he had outright called a race of gods.
And yet, when he spoke of this Muzan, his tone was filled with disdain.
Even her grandfather, the God of Shinobi, hadn't lived anywhere near that long.
"Demons… that can't exist in daylight?"
At a secluded hot spring, Jiraiya lowered his binoculars and read the diary, his expression twisting slightly.
"Chasing immortality until you're neither human nor demon… sounds just like Orochimaru."
The image of Orochimaru flashed through his mind.
To him, it was the same kind of existence.
"Yoriichi? Chopped into pieces?"
Namikaze Minato also read through the entry, a look of confusion crossing his face. Unlike before, where he could at least grasp part of the context, today's contents left him completely at a loss.
"Thunder Breathing… a new technique?"
Uchiha Itachi studied the entry thoughtfully. It seemed to be some kind of sword style.
Which meant Sasuke, under Kaede's guidance, was growing stronger.
That was… good.
[During the battle in the Infinity Castle, the moment that scumbag boss Muzan got blown up like a bullfrog, he must have finally realized how disastrous it was to skip background checks when hiring. All those cold-blooded, man-eating subordinates of his actually had the potential to be moved by love!
Except for one—Kaigaku. That guy was pure trash.
Zenitsu must have deliberately tanked his ranking for who knows how long just to get matched with him.
Hahaha, when the Sound Hashira heard the report from the Kasugai crow, he was probably completely stunned. "Wait, you soloed an Upper Rank Six? Then what were we doing when we teamed up to beat one? Was I holding you back?"]**
Reading the diary's continued mockery of Muzan, everyone couldn't help but smile. Even if they didn't fully understand it, it somehow felt amusing.
Then, suddenly, a video appeared below.
Following their now-familiar routine, they immediately opened it.
At the beginning, outside a quiet, secluded mansion, a man dressed in a white suit and cloak stepped forward through the mist.
The moment he appeared, everyone's hair stood on end.
A powerful aura radiated from him—but it wasn't the presence of a human powerhouse.
It felt like something else entirely.
Like a monster wearing human skin.
Aside from Sasuke, those watching the diary were all experienced fighters, and they trusted their instincts.
Could this be what Kaede had mentioned before?
A demon?
A creature that only appeared at night?
There were tales of demons in the shinobi world as well, but most were either fabricated or the work of shinobi disguising themselves.
"Could he be that 'scumbag boss'… Muzan?"
Hatake Kakashi murmured under his breath.
The man didn't look human at all—especially those eerie crimson eyes in the darkness.
He stepped into the house.
Inside, there were others.
A man lay there, his body covered in festering wounds, wrapped in bandages, barely clinging to life. Beside him stood an ordinary woman.
Compared to Muzan, the grotesque man actually seemed more human. His appearance was horrifying, but his essence was unmistakably that of a human being.
"We're meeting for the first time, aren't we, Kibutsuji Muzan?"
The man lying there spoke.
The moment he did, everyone froze.
That voice…
It was unmistakably familiar.
It sounded exactly like the Fourth Hokage, Namikaze Minato.
Even Minato himself was momentarily stunned, almost thinking it was truly him.
But there was a difference.
The man's voice was softer, weaker—lacking the vitality that Minato's carried.
Was it just a coincidence?
"What a hideous appearance, Ubuyashiki."
Muzan looked down at the man before him, the last leader of the clan that had caused him endless trouble, a trace of mockery on his face.
"So you've finally come," Ubuyashiki said, turning his head toward Muzan. Though he couldn't see, he could sense the presence of the enemy his clan had pursued for a thousand years.
"Our clan… the Demon Slayer Corps… we have hunted you for generations."
He even had his wife describe Muzan's appearance to him.
At that moment, everyone fully understood.
This terrifying figure was indeed the creature Kaede had described—a monster that had lived for centuries, even millennia.
No longer human.
A being that had endured for a thousand years.
By their reckoning, that meant stretching back to the era of the Sage of Six Paths—or even beyond.
"I knew you would come," Ubuyashiki continued. "You hate me. You hate the Ubuyashiki Clan. That's why you would come here personally to kill me."
"I find this utterly tedious," Muzan replied, his gaze cold. "A clan that has interfered with me for a thousand years… and its leader has fallen to such a pathetic state. How unsightly."
"You already reek of death, Ubuyashiki."
At those words, Ubuyashiki struggled to sit up.
"Of course I do," he said, coughing violently. "The doctors told me half a year ago that I had only days left. And yet, I'm still alive."
He let out a strained breath.
"The only thing sustaining me… is my obsession with destroying you, Muzan."
Silence fell.
Though the exchange had been brief, combined with the diary's earlier entries, it revealed something chilling.
There existed creatures in this world—beings wearing human skin, known as demons.
They could not survive in sunlight.
And they devoured humans.
At their head stood this elegant man, indistinguishable from a human at first glance.
And opposing him…
Was the Ubuyashiki Clan, supporting an organization called the Demon Slayer Corps.
Their leader was a man with no trace of cultivation, a man who could barely even survive.
And yet, he stood at the center of it all.