The space twisted the senses, and when Misaki now known as Zero suddenly appeared here, she felt an intense sense of dislocation.
The entire area seemed upside down. She looked up, and countless staircases and corridors spiraled overhead and around her. The warped space defied human geometry, pressing the coffin-like weight of gravity against her feet.
She wanted to understand where she was, but her curiosity was not particularly strong. At this moment, far more pressing thoughts and sensations dominated her mind.
A rapid, urgent sound of the biwa echoed incessantly. Above her, at the end of a staircase, a woman played the instrument, and from her, fear radiated and twisted outward.
Suddenly, with the sharp note of the biwa, Zero found herself transported to another space. In front of her stood a woman dressed in an ornate black kimono, her gaze cold and indifferent.
"Lord Muzan," Zero immediately knelt, her respect unquestioning. No understanding was required; the act of kneeling was enough.
She didn't care about the blood still staining the floor or the convulsing lower-rank demon nearby. Muzan, supreme and self-centered, did not want questions. His whims ruled absolute.
"You are the last of the lower-rank demons to arrive," Muzan said, his gaze piercing through Zero. "Explain yourself."
"My lord, I needed time to heal my injuries. I also had to find some blood for sustenance," Zero said softly.
Muzan's eyes narrowed slightly, but he accepted her explanation. He could still feel his absolute control over this insignificant creature the power to grant or take life effortlessly.
Even when it seemed she might escape his grasp, that was merely an illusion born of overthinking. No demon could truly defy him, except in death or in special cases like Tamayo.
"Aside from you, only one lower-rank demon remains," Muzan said coldly. "You are too weak to be of any use. That is why you are no longer needed."
The Twelve Kizuki were created to help Muzan locate the blue spider lilies. Based on the initial partnership with Kokushibo, the hierarchy was extreme. The gap between upper and lower ranks was massive, and no lower-rank demon had ever risen to the upper ranks through merit. Strong demons seemed destined from birth, while the weak could never surpass their limits.
For Muzan, the lower ranks were worthless. He could create hundreds of them at will. Only the upper ranks held value.
For centuries, upper-rank members had remained unchanged, their power cliffs defining the hierarchy. The difference between Upper Six siblings and Upper Five Gyokko or Upper Four Hantengu might be minor, but Upper Three could be killed easily. Upper Three, Akaza, was still weaker than Upper Two, Douma. And Upper One, Kokushibo, was a force even Muzan had to respect.
Any upper-rank demon could effortlessly annihilate all lower-rank members. After centuries of tolerating these weaklings, Muzan's patience had finally run out.
If they were useless, better they die and become his sustenance.
"Ah, Lord Muzan has arrived early! And enjoying a few treats, perhaps?"
A playful, carefree voice rang out. A man with pale oak hair and prismatic eyes appeared, dressed in lavish clothes.
"Are the remaining two snacks left for us, your subordinates?" he teased.
"Mind your attitude toward Lord Muzan," said another, a young, muscular man with short dark red hair, sternly pushing the flamboyant man's hand away. "And stay away from me."
"How terrifying! Lord Muzan is beginning to eliminate the Twelve Kizuki," whispered a frail, elderly figure descending the staircase. Compared to the others, he exuded no dominance.
"Don't worry, Hantengu. If Lord Muzan has a good appetite, he'd devour us one by one," said a strange demon emerging from a porcelain pot, a mouth in place of its eyes, twisting like a genie from a lamp.
"Lord Muzan remains as beautiful as ever! Even in another body," gushed a well-dressed, blushing female demon.
These were the Upper Ranks. Zero bowed nearly to the floor. The presence they exuded pressed down like a predator upon its prey.
"So, Lord Muzan, after all this time, has allowed us to gather. Surely this means something significant," teased Douma, Upper Rank Two, his demeanor dangerously casual.
"Blue spider lilies, and eliminating the Demon Slayer Corps your two objectives remain unfulfilled," Muzan said, cold and furious. The veins on his neck bulged with anger and impatience.
"I am beginning to doubt whether your existence is necessary."
Even so, his words were enough to subdue the Upper Ranks instantly. Upper Six Daki, Upper Five Gyokko, and Upper Four Hantengu prostrated themselves. Upper Three Akaza knelt on one knee, while Upper Two Douma mimicked him lazily. Only Upper One Kokushibo remained seated, unmoving.
The hierarchy and power of the Upper Ranks were clear. For Muzan, three strong Upper Ranks would suffice. Any one of them could easily kill the Lower Ranks.
"But today, you are gathered for a task," Muzan said, looking at Zero. She could no longer control her body, forced to stand before him, tearing out the numbered eyeball from her socket.
"There is a troublesome individual you must deal with either die at his hands, or at mine."
Muzan crushed the eyeball and flicked it into the Upper Ranks, blood seeping into their heads. Zero gritted through the pain, not daring to cover her missing eye. Muzan enjoyed asserting authority at every opportunity.
"Interesting," Douma said, recognizing the image of the Demon Slayer in Zero's memory. "Is she the sister of the child I devoured?"
"Fool. Lord Muzan wants your attention on someone else," Akaza snapped, fists clenched, the war thrill boiling.
"Such skill. I didn't know a swordsman like this still existed," Kokushibo murmured, gripping his sword, excitement surging.
He believed this swordsman, Shiro Mukai, though young, was the second strongest he had encountered, rivaled only by the legendary master he remembered.
Muzan observed Kokushibo's excitement but tolerated it. Kokushibo was not a subordinate, only a partner powerful and independent, yet still one of Muzan's sharpest weapons.
"Where is this interesting individual?" Douma asked. "I can send my men; someone this reckless should be easy to find."
Muzan's veins twitched, but he allowed it.
"Your usual duties remain unchanged," Muzan said coldly. "But if you spot this person, gather everyone to kill them. Do not act alone. Understood?"
Upper Ranks Four, Five, and Six acknowledged immediately. Akaza frowned but complied. Douma smiled lazily, unconcerned. Kokushibo remained silent, his stance revealing his distrust of his peers. But as Muzan's orders, he would not defy them.
"If you encounter this individual head-on..." Kokushibo's hands twitched, blood long dormant now warm with anticipation.
"Daki, I have high expectations, but you and your brother are talented. Talent, however, is the least valuable thing in this world," Muzan said to the youngest, softening slightly.
"If you face that monster, do not engage first. Preserve yourself; your survival serves me more."
"Yes, Lord Muzan!" Daki exclaimed, while her brother, Gyutaro, remained silent, fully aware of Muzan's reasoning.
Yoshiwara, a chaotic district, provided the perfect intelligence network. Daki's limited intellect was supplemented by Gyutaro's analysis. Among the Upper Ranks, Gyokko competed in information gathering but Muzan still stressed Daki's safety.
"You will use human authorities to ensnare him," Muzan explained, praising Gyutaro's cleverness. "Let him taste being trapped and betrayed."
This method of using humans against humans maximized Muzan's advantage.
"Daki, Gyutaro, this mission is yours."
"Yes!"
Finally, Muzan turned to Zero. A massive, bloodied, eye-covered tentacle emerged from the shadows, ready to devour her.
Zero did not move. Muzan paused.
"Due to your performance, you shall live," Muzan said coldly. Perhaps he was appeased by having dealt with the Lower Ranks, or by Zero's fearless demeanor.
Yet survival did not mean mercy. A spike of blood pierced her neck, forcing her to kneel, convulsing. Muzan's cold voice instructed:
"Digest this blood or die. You and Enmu will focus on the demon slayer with the earrings. Now, move."
At his command, the music of the biwa began again, and all were transported out of Infinity Castle.