The news that Tanjiro and his crew had slain an Upper Moon demon without any casualty sent a ripple across both factions. The Demon Slayers were in an uproar.
This was the second Upper Moon that had been killed in just few months. This was unprecedented in history.
At least, now the demon slayers were motivated, feeling enthusiastic about slaying more demons.
The Infinity Castle wasn't taking the news happily, though.
A dark shadow was cast over Muzan's face as the Twelve Kizuki felt unbearable pressure washing over them. Even Kokushibo locked his brows tightly.
"Foolish humans..."
Muzan's voice echoed with heavy restraint, barely containing his rage.
The Twelve Kizuki quivered under the oppressive weight of the voice.
"You all have become so complacent that even weak humans can kill you, eh?"
His grin, usually cold and indifferent, was laced with anger. Slowly, his anger cooled off into temporary calmness.
"Nakime..."
The one-eyed demon quivered at the mention of her name, yet she obeyed by bowing.
"I have asked you repeatedly to find the Demon Slayer's Headquarters. Any progress?"
Even though she feared the consequences, she refused to lie and complicate matters.
"N—"
Before she even completed her words, Muzan had already acted. His arm transformed into an enormous grotesque snake that clamped its jaws shut on her.
"Eeeeeaaaaaaaaahhhhhhhhhhhhhh!!!!!!!"
Nakime's wail sent a shiver down the spine of the other demons. This was the worst they'd heard her suffer. Kaigaku tensed involuntarily.
'So this... is what being a demon under Lord Muzan means.'
He began regretting his choice, attracting Muzan's attention towards him.
"You want to run?"
Muzan's inhuman eyes loomed over him. Then a chilling smile spread across the face of the Demon Progenitor.
Kaigaku paled at the sight, terrified.
Muzan dropped the quivering body of Nakime and slowly walked towards him.
His arm, which had taken the form of a snake suddenly shifted into a stinger and stabbed Kaigaku in the heart, pumping blood into the Upper Moon's body.
"Ugh! Uwaaahhh!!"
The demon cried as he rolled in agony, the bitter pain of evolution gnawing at his soul.
This act surprised the other demons. Why had Muzan suddenly decided to give Kaigaku more of his blood? They would come to know later.
Ignoring their thoughts and the pained demons, Muzan shifted his gaze to the Lower Moons.
Those demons barely kept their composure. Well, except for that eccentric demon Kurayami. He remained the same, oddly calm and collected. Infact, his crescent eyes seemed to glow brighter.
"I would have killed you all if it weren't for the fact that Kokushibo personally handpicked you. Still... I won't let you know peace if you bring no results." He paused. "Especially you... Kurayami. You remind me of someone rather unpleasant."
Kurayami's voice, barely a whisper, reached his ears.
"Very well, Lord Muzan. I will thoroughly amuse you."
His reply earned a scoff from the Demon Progenitor, though he didn't dwell on it.
Instead, he turned back to Kaigaku. "The Butterfly Mansion has already been exposed. Though it seems none of you deemed it worthy of attacking since the Hashira's disappearance."
"Kaigaku. You must vanquish that place... else, my curse would vanquish you instead."
Kaigaku trembled, the echoes of pain from the evolution lingering within him.
"I shall heed your command, Lord Muzan."
He bowed with gritted teeth. Then he looked at every single Upper Moon. Daki, Gyutaro, Akaza, and finally Kokushibo.
'I will... without a doubt, surpass you all!'
His determination rose like a great wall, seemingly unstoppable.
....
[Eternal Paradise Cult]
"Hooo..."
Shinobu exhaled a hot breath, then opened her eyes.
She had been meditating for hours, deep in concentration. She had expected to at least achieve some results, but surprisingly, her gain was massive. She could harness hamon without much difficulty.
Though, she didn't expect that Douma's smiling face would be the first thing she saw when her eyes opened.
"Mm? Shinobu-chan surely has great talents~"
He flattered with a flattering smile that made Shinobu's eyes twitch.
Why the repetition...
"Ugh! You're annoying."
She shot him a glare, annoyed. What was he even doing here.
As if he didn't notice her annoyance, Douma smiled brighter and produced a small ice sculpture of Shinobu.
"Shinobu-chan, take a look. Isn't this simply beautiful?"
The twitch on Shinobu's eyes grew stronger, almost turning into a popped vein.
'You bastard-!'
"Mn, mn. I knew Shinobu-chan would appreciate it."
He laughed heartily, then stood up like a noble lady. He suddenly remembered Lord Kokushibo—that man was like a noble lady. Graceful and elegant.
'Uwah! I miss my colleagues...'
He sighed, feeling down.
"Anyway. Shinobu-chan has such obvious talents for Hamon. Would you like to try training now?"
Shinobu took a deep breath, preparing herself for the illusion again.
'Once I'm done with a few days of training, I want to return to the Butterfly Mansion. I miss Kanao and the three girls.'
'?'
Her thoughts abruptly shifted into alarm when she saw a golden fan sweeping at her neck.
Clang!
She responded with a swift counter of her nichirin blade. Unsure whether this was reality or an illusion, she fought cautiously.
...
Meanwhile...
Douma watched Shinobu, frozen in her seated position. The instant she opened her eyes, he had pulled her into an illusion.
His face, usually full of smiles, was now a mask of indifference.
'Things are going to be advancing quite quickly... I'm sure Muzan wouldn't be so patient whenever it concerns the Blue Spider Lily, would he?'
'I have to prepare too... He might send that noble lady. Like, who knows?'
With the thought in mind, he submerged himself in an illusion where he faced off against Kokushibo. The world around him bled into a plain land stretching hundreds of meters. This was his newly created technique called Reality Simulation.
With it, he could immerse himself into any situation he wanted.
'Even censored acts...'
The thought disappeared when he saw that terrifying demon though.
"I see."
Kokushibo's six eyes locked onto him perfectly. He didn't say any other useless words. Instead, he drew his sword.
"Come."