"It really has been... so long since I last saw this."
With his eyes lowered, Ubuyashiki Kagaya gazed up at the night sky.
"When was the last time I looked up at the stars like this? Was the sky then as beautiful as it is now?"
Because of his illness, Kagaya's eyesight had worsened day by day. Indoors, he managed, but outside he always needed someone to help him walk, or else he'd risk stumbling simply because he couldn't see his own feet.
A simple fall might mean nothing to most people, just a little pain, but for the frail Kagaya, it was different. Even swinging a sword could send his pulse into chaos and trigger muscle spasms. For him, one careless fall could easily lead to serious injury.
"Congratulations on your recovery, Oyakata-sama!"
At that moment, all the Hashira knelt together before Kagaya, bowing respectfully to celebrate his restored health.
"Ah... Namu Amida Butsu."
Himejima Gyomei, overwhelmed with emotion, wept as if a dam had burst, unable to hold back his tears. "This is truly the protection of the gods and Buddhas... The gods must indeed watch over a kind and just person like Oyakata-sama. Nightingale-san is truly a blessing sent by the heavens..."
Nightingale... she really did it!
Kochou Kanae screamed with joy in her heart, her face unable to hide her delight.
The stars above were beautiful, captivating even, but Kagaya soon lowered his gaze to what was far more precious to him.
His children—the Hashira of the Demon Slayer Corps.
"Sanemi, you've got even more wounds than before... Gyomei, if I look carefully, you're even more muscular than before. You all must have endured hardships I can't even imagine..."
With his sight restored, Kagaya could finally see details he'd long missed.
Compared to his memories, everyone had changed—some more, some less. These changes brought Kagaya both comfort and heartache.
"We're terribly sorry to have worried you, Oyakata-sama."
Sanemi bowed his head, his tone humble.
"Namu Amida Butsu... Slaying demons is our duty, nothing more," Gyomei replied solemnly. "The one who truly suffered most is you, Oyakata-sama, toiling so hard even while gravely ill. Now that hardship has turned to happiness, we must thank Nightingale-san properly."
Speak of the devil—Nightingale emerged from the house just then. Only now did everyone notice the deep furrow in her brow, and that she was muttering to herself.
"Unwilling... I can't accept this..."
"Nightingale?"
Kanae called to her, but there was no response; Nightingale kept whispering to herself.
"I can't accept it! No matter what I do, I can't cure it... No, even if I do cure him, the illness clings to him, shadowing his every step. I can't find the source, and there are no pathogens... I can't accept this!"
Gyomei frowned slightly.
"What's happened, Nightingale=san?"
Everyone's gaze grew tense, even those who'd initially resented Nightingale—like Sanemi and Iguro—now looked at her with some respect.
Biting her lower lip, feeling both embarrassed and frustrated, Nightingale finally spoke up.
"I... I didn't truly cure his illness."
What threatened Kagaya's health wasn't just the centuries-old curse. The curse mainly destroyed his immunity, making him vulnerable to countless diseases—something more savage than HIV.
So, before even attempting to treat the curse, Nightingale first had to tackle a whole host of secondary illnesses.
For the curse itself, she relied on her unique skills and Noble Phantasm, supplemented by other methods—since her abilities could remove debuffs and even curses.
With those powers, Nightingale managed to dispel the curse from Kagaya... only for it to return two minutes later.
Cleansed, then back again. Cleansed, then back. This cycle repeated until night fell.
This curse is disgusting... and what's with that "bordered" effect?
(In FGO, buffs with borders can't be removed.)
"But..." Kanae asked hesitantly, "Oyakata-sama really does seem much better than before."
"I can't eliminate the curse completely, but the illnesses it brought, I can handle. I've also extended his life as much as possible."
Nightingale explained, "He should have another ten, maybe twenty years."
"That's..."
Kanae clenched her hands, biting her lip in frustration.
"No need for that, Kanae. To feel this healthy again, to have even ten more years—this is luck beyond what any Ubuyashiki before me has ever known. Why would I complain?"
Kagaya smiled, light and gentle. As the patient himself, he soothed everyone's worries.
"Besides, as long as we defeat Kibutsuji Muzan during this time, the curse that's plagued our bloodline for a thousand years will end with me."
His eyes sparkled, softer and warmer than ever before. Meeting his gaze, the Hashira felt a surge of determination.
"Yes! We'll wipe out every last demon, defeat Kibutsuji Muzan, and restore Oyakata-sama's health once and for all!"
"I believe in you."
Suddenly, a terrible shadow seemed to fall over them. Even the starlight above dimmed as if swallowed by darkness.
No one could see it, but everyone felt it—somewhere, a pair of crimson eyes opened, bearing down on them with crushing force.
"Kibutsuji Muzan... So if we take him out, we can cure the curse, right?"
Nightingale's voice was low and heavy, turning the air thick as mud. "In other words... he's the pathogen. The virus that must be eradicated. Isn't that right?"
Ever since confirming this was the world of Demon Slayer, Nightingale knew about the infamous but—frankly—overrated final boss, Kibutsuji Muzan. She'd never really cared about him, even though she had the power to end him. She simply hadn't felt the need to seek him out.
Nightingale—or rather, Fenghuang—cared most about those in front of her. Her approach was more like Himmel's: even knowing there was a demon king threatening the world, she'd never turn her back on anyone in need right now.
She hadn't gone after Muzan on principle. The only reason she'd killed Dōma and the others was because they picked a fight with her first.
But now—after taking Kagaya as her patient—she had finally set her sights on Kibutsuji Muzan.
At the same time...
CRASH!
A test tube slipped from Muzan's hand, shattering on the floor and spilling pale blue liquid everywhere.
Standing tall in his immaculate suit, Muzan stared at his now-empty right hand, bewildered.
His control over his own body was near perfection—he could command every cell. Yet just now, he'd failed to hold onto a test tube? Let it fall and shatter?
What was that chilling sense, as if some terrible predator was watching me...?
Muzan couldn't understand it.
No, no! I am the strongest, the most perfect being on this earth, the apex of the food chain—how could anything possibly frighten me?!
He shook his head violently, laughing off the absurd premonition.
That's right. I am immortal. I am fearless. Kokushibo is dead! The Sun Breathing style is extinct! Once I crack the secret of sunlight, even my last weakness will be gone. Then nothing in this world can kill me!
Having convinced himself, Muzan returned his focus to his experiments. Since his underlings had failed to find the Blue Spider Lily, he'd spent years searching for substitutes.
So...
"What did you just say?!"
A collective shout shattered the quiet of night, echoing throughout the entire estate.
"You just said... Kibutsuji Muzan!"
"Do you know how to find that bastard?!"
"Even we Hashira have never seen him in person—"
"Do you know where his lair is?!"
"Nightingale-san!!"
Surrounded and peppered with questions, the Hashira buzzed around Nightingale like a nest of hungry chicks clamoring for food. She frowned, feeling the din was almost unbearable.
Still, not a single one laid a hand on her—not even the brash Sanemi, who held himself in check out of respect for Nightingale's deed in saving Kagaya.
Even if she hadn't broken the curse for good, she'd dramatically improved Kagaya's health and given him at least ten more years. Someone like Sanemi might never say "thank you" aloud, but his attitude had clearly shifted.
At this, Kagaya gently raised a finger to his lips, and the Hashira—who'd just been as noisy as a fish market—fell instantly silent.
"Nightingale-san, could you explain what you mean? I'm quite curious about your words myself," Kagaya said, his gaze gentle and bright. "I'm beginning to believe, you truly are a miracle sent to us by the gods and Buddhas. One surprise after another."
Nightingale looked around at the earnest, expectant faces, then turned to Kagaya as their leader.
"My student, Kochou Shinobu—she wanted the power to destroy demons. But she's small, and it's hard for her to sever a demon's neck. So I gave her a way to kill demons without decapitation—using wisteria poison."
"While researching demon-killing poisons, I studied demon blood. And I discovered—the reason demons fear the sun is because they lack a vital medicinal herb."
What Nightingale spoke of was none other than the Blue Spider Lily—what Muzan had sought in vain for a thousand years.
"A herb that could help Kibutsuji Muzan withstand sunlight...?" Kagaya's expression grew solemn. "That makes sense. Sunlight is the only thing that can kill Muzan. He must have tried countless ways to overcome it in a thousand years... If he knew the herb he needed was here, he'd stop at nothing to get it."
"And he'd come himself, not send any of his minions," Nightingale added. "Because the herb works on any demon."
"Muzan is far too jealous and prideful. He'd never allow any of his minions to become perfect before he did."
Kagaya laughed quietly, as if mocking Muzan's pettiness.
"Isn't that perfect, then?"
Sanemi's temple throbbed with rage, hatred for Muzan pouring from every word. "If that coward dares show his ugly head, I'll cut it clean off!"
"But... isn't this plan extremely risky?" Kanae asked worriedly. "If we fail, and Muzan gets the herb and conquers sunlight..."
"Then we'll have lost our only way to kill Muzan," Gyomei finished for her. "The world would be plunged into a hell beyond imagining..."
"What about spreading a false rumor? Trick them into thinking we have the herb, when we don't..." Iguro suggested quietly.
"Would Muzan believe it? He's so cautious and paranoid—would he really take that risk for an uncertain rumor? Especially with Nightingale here, who's already defeated three Upper Moons?" Kanae wondered.
Kagaya rubbed his chin, thinking for a moment before turning again to Nightingale.
"So, Nightingale-san, do you know where the herb is?"
"To be precise, I don't know its exact location," Nightingale replied calmly. "But I know who can help us find the Blue Spider Lily."