— — — — — — —
"Master! It's not that I won't use it—it's that it failed! For some reason, my spatial abilities aren't working here!"
Nakime shouted in a panic.
"What?!" Muzan's face twisted in shock. "Are you sure? Try again! Now!!"
"I've tried! Ten times! Every single attempt failed!" Nakime was on the verge of tears.
"Oi! Oi! Oi!"
"Why are you in such a rush to leave?"
At that moment, Renzo strolled in at a leisurely pace, a cheerful smile on his face as he looked at Muzan. "Muzan Kibutsuji, the famous Demon King, I came all this way just to see you."
"I even planned a little sunbathing session for you—why are you trying to run away? That's not very hospitable, is it?"
Muzan's expression darkened instantly.
Sunbathing?
"Are you kidding me?! You're literally trying to kill me!"
"What the hell are you? Why can't Nakime use her spatial abilities?!"
Muzan's mind was working overtime, scrambling for answers while simultaneously stalling for time.
Renzo saw through him immediately but played along. He, too, needed time—for a different reason.
"Because," Renzo answered slowly, "you're already trapped inside my domain: Takamagahara's Projection."
"In this domain, your spatial techniques are useless. The only way out? Defeat me." Renzo smirked as he spoke.
While he talked, he silently activated his mind-reading ability, diving into Muzan's thoughts.
Logically speaking, as the final boss, Muzan should have had unshakable resolve and immense mental fortitude. It should have been difficult for Renzo to read his mind.
And yet, to Renzo's surprise—
Muzan's mental power, while strong, was nowhere near Renzo's level. Both in quality and quantity, he fell short.
Even worse, his willpower was... mediocre. In fact, many of the Hashira had stronger resolve than him.
"Seriously? This is the so-called ultimate big boss?"
Renzo was baffled—but also pleased.
If Muzan was this weak mentally, then reading his memories would be a piece of cake.
Sure enough, Muzan didn't even notice his mind was being invaded, let alone resist it.
"I see… It's because he's a coward. All these years, he never recovered from the fear instilled by the great Yoriichi. If anything, it's only gotten worse."
Renzo smirked as he pieced it together.
Muzan, the so-called Demon King, had been traumatized beyond repair.
"Takamagahara's Projection? A domain?! Since when did humans have abilities like this?!"
Muzan gasped in shock.
Of course, he was genuinely shocked—but he was also stalling.
The name Takamagahara wasn't just any ordinary title. It referred to the home of the gods in Japanese mythology.
Muzan had no idea why Renzo was willing to chat with him instead of attacking outright.
Was he just toying with him?
Did he enjoy watching him struggle in vain?
If that was the case, Muzan would gladly play along.
As long as he could escape, nothing else mattered.
"Heh..." Renzo chuckled. "Humans? Of course not. But I'm not just a human, am I?"
Then, as his grin widened, he added, "And since I've already gotten what I came for, it's time to wrap this up. Muzan Kibutsuji, let's start with a little sun exposure, shall we?"
Renzo had finished extracting Muzan's memories—including the research notes of the doctor who had originally created the Blue Spider Lily medicine. Muzan, paranoid as ever, had memorized every detail. That saved Renzo a lot of trouble.
Slash!
Without warning, Renzo swung his blade, sending two flying slashes straight at the ceiling.
Boom!
The entire roof shattered.
"Sunny Day!!"
Renzo raised his hand, gathering an orb of light resembling a miniature sun.
The glowing sphere shot upward, rapidly expanding as it reached the sky. In mere moments, it erupted into a blinding, sun-like radiance, flooding the entire area with light.
"AAAAAAAHHHHHH!!"
"NOOOOOOO!!"
"Where did this sunlight come from?! Isn't it nighttime?!"
"Impossible!!"
As the golden rays washed over them, the demons caught in battle with the Demon Slayer Corps screamed in agony. Smoke sizzled from their bodies as their skin began to burn away, turning into ash.
Although the effect was significantly weaker than true sunlight—only about one percent of its actual power—it was still enough to terrify the demons.
Frantically, they scrambled toward the safety of the Infinite Castle's shadows.
"Could this be… Renzo's doing?"
Tomioka Giyu murmured in disbelief.
Who else could possibly pull off something like this?
"Just how many hidden abilities does Renzo have?" Giyu wondered. "Creating a sun at night… Even if it's not as powerful as the real thing, the fact that it can harm demons at all is terrifying!"
"Wait!"
"Where do you think you're going?!"
"Don't even think about running! Get back here and fight!"
The Hashira weren't about to let this golden opportunity go to waste. Renzo had just created the perfect battlefield—how could they not take advantage of it to wipe out the demons?
"AAAAAHHHH!!"
Muzan and Nakime shrieked as the artificial sunlight scorched their flesh.
Then, in a sudden act of desperation, Muzan grabbed Nakime and threw her toward Renzo before dashing in the opposite direction at full speed.
Halfway through his escape, his body suddenly exploded into more than 1,800 pieces, scattering in all directions in a desperate bid to flee.
For someone hailed as the ultimate big boss in the Demon Slayer World, this was downright embarrassing.
He didn't even have the guts to fight Renzo and instantly resorted to his final, most desperate survival tactic—running away.
The title of the "King of Cowards" was now truly well-earned.
"Heh! You think I'll let you get away?"
Renzo let out a cold chuckle. With a flick of his wrist, his blade, Kyoka Suigetsu, flashed through the air, effortlessly beheading Nakime.
Then, raising his sword above his head, it became completely enveloped in a platinum-colored glow, sunlight continuously gathering and condensing around it.
"Sunlight Slash!!"
In the next moment, he swung his sword down.
A massive, blazing slash composed entirely of sunlight erupted from the blade, stretching over ten meters in length as it shot toward Muzan's scattered remains.
Upon reaching the core of Muzan's fragmented body, the slash exploded, engulfing a hundred-meter radius in radiant light.
The attack was simply too fast. Muzan's 1,800 pieces hadn't even managed to spread far before being consumed by the scorching sunlight.
"AHHHH!!! NOOOO!!!"
Standing his ground, Renzo calmly listened to Muzan's final, despairing scream, shielded by a psychic barrier.
Using his mental perception, he carefully confirmed that not a single piece of Muzan remained. Simultaneously, as Muzan perished, the other demons across the battlefield began disintegrating into ash.
Only then did Renzo relax.
"It's finally over. Mission complete."
Sheathing his sword, he stretched lazily before turning toward the exit of the Infinity Castle, walking away at an unhurried pace.
He had initially expected to use Kyoka Suigetsu to deal with Muzan directly, but the guy was such a coward that he didn't even put up a fight.
Still, fusing the Harsh sunlight skill he got from Eevee with his swordsmanship and unleashing it as a massive, expanding explosion had been a successful experiment.
---
"These demons… are disappearing?"
"Our side too! Does that mean…?"
Everyone stared at each other, realizing the same thing.
"It's Renzo! He must've killed the Demon King!"
"Hahaha! That's insane!" Rengoku Kyojuro burst into hearty laughter. "We haven't even taken down a single Upper Moon Demon, and he's already finished off the Demon King?!"
"It's more than that," Kanae added with a smile. "Don't forget—we haven't seen Upper Moon One, Kokushibo, at all. If he didn't simply happen to be absent, then the most likely explanation is that he attacked Renzo… and got taken care of before Muzan."
A soft chuckle sounded from the distance as Renzo emerged from the ruins of Infinity Castle.
"Sharp as ever, Kanae. You got it in one."
"Call me big sister, little Renzo," Kanae playfully scolded, her cheeks tinged with a faint blush. Then, her expression turned serious. "So… Muzan is truly dead?"
Everyone turned their expectant gazes toward Renzo.
They had already pieced things together, but they wanted to hear it directly from him.
"Yes," Renzo nodded with a small smile. "The Demon King is dead. There will be no more man-eating demons. You're free to celebrate now."
"OOOOHHHH!!!"
"We did it!!"
"Father, Mother, my little brother, my little sister—you hear that?! The Demon King is dead! The demons are gone! Your souls can rest in peace now!"
"Dad… sob…"
"My love…"
"This is the best day of my life!"
Tears streamed down the faces of the Demon Slayer Corps warriors as they whispered to the spirits of their lost loved ones.
Every single Hashira had lost family and friends to demons.
That was why they had joined the Demon Slayer Corps—to take revenge, to prevent others from suffering the same loss.
For generations, Demon Slayers had passed down their will, sacrificing everything for one goal: the eradication of Muzan Kibutsuji and the annihilation of all demons.
And now, that dream had become reality.
Words could not begin to express the overwhelming joy and relief they felt at this moment.
"Thank you, Renzo! Thank you for giving us this future!"
Led by Kanae, the Hashira stepped forward and bowed deeply to Renzo in gratitude.
The battle had been swift, and they hadn't even managed to kill a single Upper Moon Demon themselves.
But this fight had shown them the immense gap between themselves and the Upper Moons—let alone Muzan.
Had it not been for Renzo, they would have suffered immense casualties.
Even then, it was doubtful they could have exterminated all the demons, let alone Muzan himself.
Everything—every victory they now celebrated—was thanks to Renzo.
Moreover, the intelligence, the extraction of Infinity Castle from the underground, and all their strategic advantages had been his doing.
They all had the same thought: Renzo hadn't needed them at all.
He could have solo-cleared the entire Infinity Castle like it was an RPG dungeon, wiping out Muzan and his demons without any help.
But he had chosen to include them.
Perhaps it was so they could witness the moment the demons were eradicated.
So they could fight for their fallen comrades.
And for that, they were endlessly grateful.
.
.
.