"Why, you say?"
Upon hearing Muzan's question, Riezel tilted his head slightly.
"At this point, you're still asking why? Does it even matter?"
Riezel's words made many blood vessels appear in Muzan's eyes.
"I just want to survive! What have I done wrong?!" Muzan shouted in anger.
Indeed, in a way, Muzan was quite innocent.
Before he was even born, the shadow of death had tightly wrapped around him.
While in his mother's womb, he was so weak that his heart stopped beating several times. Even though he was eventually born by sheer luck, he was in a state similar to a stillborn and almost died right after birth.
Although he had desperately clawed his way back from the brink of death and managed to survive, he was still diagnosed with a terminal illness and was told he wouldn't live past twenty.
If he had just died then, he would have been someone with a tragic life, a pitiful soul countless people would feel sorry for.
In that sense, Muzan was indeed very innocent.
However—
"You have sacrificed too many lives just to stay alive." Riezel said calmly. "Is your life the only one that matters, while other people's lives are worthless in your eyes?"
"Huh? Hahahahaha—!"
Muzan paused for a second before bursting into laughter—an exaggerated, wild laugh.
"You mean to say that sacrificing others' lives to survive is wrong?" Muzan said with a sneer on his face. "What about humans? Aren't humans committing the same thing as me?"
"They also eat meat to survive, they kill living beings, putting the corpses of animals on their tables as nutrients to keep themselves alive, eating them up."
"What they can do, why can't I do?"
"Just because they cook their food to look less bloody, they're not wrong?"
"Or are you saying that because they eat animals instead of humans?"
"But I'm not human either! I'm a demon! In my eyes, humans are just talking animals!"
Muzan shouted at Riezel with an angry expression.
"Why?! Why is it wrong for me to survive?!"
Clearly, Muzan was still filled with resentment over his current fate.
Unfortunately, his words only earned him Riezel's cold gaze.
"If you really can't understand, let me put it more bluntly..."
Looking calmly at Muzan, Riezel began to explain.
"It's because everyone wants you dead and no one wants to see you survive, so no matter the reason, this is the only outcome you can expect."
"In short, no one gives you a damn."
"Got it?"
Hearing this, Muzan's expression froze.
"You should have thought about this long ago."
Riezel continued, his voice became cold.
"Since you started killing others without reason, they have every right to kill you without reason either."
"In fact, the reason has always been there; you just didn't see it as valid."
"Yeah, I get it, you're not human. But you know... if you can kill humans, and humans can kill animals, why can't we kill you too?"
"With someone as cold-blooded as you, talking about deep-seated hatred is probably beyond your grasp. Trying to explain family bonds to you would be a waste of time since you'd just find them strange, right? So, I won't explain further."
"However, there's only one thing you need to get..."
"You simply shouldn't exist in this world."
Riezel stated each word deliberately.
"Your death will give more people the chance to keep living, instead of one day unexpectedly losing their most precious life, just like you see your own."
"Do you get it now?"
"Demon."
As Riezel's words reached Muzan's ears, he fell into complete silence.
At this moment, Muzan's expression ceased to be filled with anger, hatred, or resentment. Instead, for some inexplicable reason, a profound calmness settled over him.
As Tamayo and Yushirou stumbled out from a pile of rubble, looking disheveled as they witnessed the scene, they also fell silent.
Especially Tamayo, a woman who harbored centuries-old hatred toward Muzan, watched as the demon who had been the object of her hatred for so long now only had his head held in Riezel's hand.
Although her eyes gleamed with intense satisfaction, Tamayo clenched her fists and found herself speechless for reasons she couldn't explain.
In this tense and quiet moment, Riezel turned his empty hand and retrieved the Blue Spider Lily from his storage space.
"For every beginning, there is an end... After a thousand years, it's time for you to atone for your sins."
Riezel released the Blue Spider Lily, letting it fall to the ground.
*Whoosh!*
Suddenly, a flame ignited from the blue flower, burning it to ash.
Seeing this, the jumbled thoughts in Muzan's mind seemed to vanish as if his soul had been completely drained, leaving him staring blankly at the burning Blue Spider Lily, the blood vessels in his eyes gradually fading away.
It was as if his life, his dreams, his everything, had disappeared along with the burning flower.
In his final moment, Muzan uttered only one sentence.
"…I'm a demon, but I'm not a monster..."
Muzan stared at Riezel and spoke sincerely and slowly.
"In my eyes, you and Tsugikuni Yoriichi are the true monsters..."
Unfortunately, Muzan's words didn't provoke any psychological reaction from Riezel.
"Thanks for the compliment."
After Riezel responded calmly to Muzan's 'compliment', a red fluctuation emanated from his hand, forming crimson waves that enveloped the barrier cube.
*Bzzz—*
In the next moment, Muzan's head, enclosed in the barrier cube that imprisoned him, was instantly decomposed into nothingness by Riezel's Decomposition Magic.
Like shattering glass, this scene resulted in Muzan completely disappearing from the world.
"…"
Silence pervaded the ruins.
Riezel calmly turned around, slowly sheathing Hermit that emitted high temperatures into its scabbard as if he had done something insignificant.
Tamayo and Yushirou looked at Riezel's back, feeling a mix of emotions.
"It's over…"
Yushirou mumbled in a daze.
"Yeah…"
Tamayo closed her eyes, her tone tinged with sorrow and mourning.
"Everything… finally comes to an end…"
===
It really did end.
Just as Muzan was instantly disintegrated into nothingness by Riezel's Decomposition Magic, completely disappearing from this world, within the Infinity Castle, countless demons who were fighting fiercely against the Demon Slayer Corps all froze in place.
They stood motionless.
They lost their aura.
As the demon blood within them rapidly disappeared at an astonishing speed, they ceased existing as creatures known as demons.
One by one, they turned into ash, gradually dissipating as if they were being illuminated by sunlight, disappearing without a trace in the blink of an eye.
Every member of the Demon Slayer Corps, who had fought valiantly with bloodshed, looked at each other, unable to snap out of their daze for a long time.
After a while, someone finally spoke as if awakening from a trance.
"...Is it over?"
Such a voice awakened everyone.
"Is it... over?"
"It's over..."
"It's over!"
"IT'S OVER—!!!"
They began dropping their weapons, tears streaming down their faces little by little.
Immediately after, cheers loud enough to shatter the ceiling erupted, causing all the members of the Demon Slayer Corps to either cry out or embrace each other, their faces filled with excitement and joy.
"It's over!"
"It's all over!"
"Kibutsuji Muzan is dead!"
As everyone cried and laughed, many Kasugai Crows also flew around, spreading the news.
"Head Instructor Tsugikuni Yoriichi has defeated Kibutsuji Muzan!"
"Kibutsuji Muzan is successfully defeated!"
"Kibutsuji Muzan is successfully defeated!"
In the Kasugai Crows' sharp voices, only one sentence remained—'Kibutsuji Muzan is successfully defeated!'
"Su-Succeed!"
Mitsuri cheered, surrounded by the corpses of numerous tigers.
"Excellent!"
Muichirou also rarely showed an excited expression.
"Namu Amida Butsu..."
Just as Gyoumei stepped out of the lotus pond, he heard the news and immediately clasped his hands together, tears streaming down his face.
"He did it... Elder Sister..."
Shinobu stood beside Gyoumei, holding Douma's golden iron fan, and for the first time, a sincere smile formed on her face.
"Finally dead..."
Obanai stopped in his tracks, unraveling the bandages that had been wrapped around his mouth.
"Truly... quite splendid, Head Instructor!"
Tengen burst into laughter in front of Obanai.
"That guy..."
Sanemi held the head of a small demon, watching silently as several Kasugai Crows flew through the air.
"Lord Head Instructor... Impressive."
Even Giyuu, after a moment of silence, made such a statement.
"Big Brother..."
Tanjirou, Zenitsu, and Inosuke lay battered on the ground, looking up at the sky with broad smiles.
Lastly, Kyoujurou emerged from the destroyed arena, dragging an injured arm, his resolute face adorned with a smile radiant enough to illuminate everything.
"Well done, Young Tsugikuni..."
Recalling the incredible youth who once declared on the Mugen Train to protect him, Kyoujurou felt that he might never forget that encounter that day.
At this moment, every member of the Demon Slayer Corps cheered and rejoiced, not stopping for a long time.
===
Meanwhile, in the Swordsmith Village.
By now, the sun had already risen.
"Master..."
""Father!""
At this moment, Amane and her children shed tears of joy because Kagaya stood up without difficulty or help.
When they saw his figure, the decaying traces on his body gradually disappeared.
Feeling the long-lost strength and vitality flowing through him, Kagaya realized for the first time that he could move simply because he was still alive.
"He... He won... He won..."
Kagaya smiled with tears streaming down his face.
After a millennium, the curse of the Ubuyashiki family finally disappeared on this day.
Under the sunlight, Kagaya and his family embraced each other, welcoming a new and vibrant day with tears of joy.