Oboro listened carefully as Doma recounted his betrayal of Muzan alongside Kokushibo. The revelation was staggering: Akaza, the formidable Upper Moon Three, had been devoured by Gyutaro. Gyutaro and his sister Daki had eliminated both the Fifth and Third Upper Moons in one decisive strike, marking their complete allegiance to a new cause.
However, Doma's treachery extended far beyond simple betrayal. He exposed every detail of Muzan's current abilities, revealing the Demon King's deepest secrets. Despite bearing the heavy psychological burden of his past encounters with Yoriichi Tsugikuni, Kokushibo's samurai spirit remained unbroken; death held no fear for him. Similarly, Doma's lack of basic human emotions rendered him incapable of experiencing genuine terror, even when facing his own mortality.
Their surrender wasn't born from cowardice. Both demons had reached the same calculated conclusion: In a direct confrontation, Muzan's side would most likely fall. More importantly, they sought something greater: a transcendent power that would surpass their current limitations.
Muzan and the Inheritor had both demonstrated the ultimate evolutionary potential of demon blood. Muzan's newfound abilities originated from the Inheritor's consciousness. Since Oboro had transformed the Inheritor, everything Muzan possessed ultimately traced back to Oboro's influence.
After his lengthy explanation, Doma finally revealed their ultimate objective: "We want to become successors."
Oboro's expression remained thoughtful. "Nakime hasn't activated her Blood Demon Art to summon you to the Infinity Castle yet. This means Muzan remains unaware of your betrayal. Once he discovers the truth, you're both dead men walking."
Nakime's terrifying ability could instantly transport any of the Twelve Demon Moons to the Infinity Castle, Muzan's primary location for meetings and maintaining control, regardless of their location. Doma and Kokushibo understood this perfectly, which explained their desperation.
"Are you interested in killing Muzan?"
The cool night breeze swept across them as the white-haired Oboro smiled knowingly.
"To Muzan, we're merely tools for his use," said Kokushibo for the first time, his voice carrying centuries of suppressed resentment. "The blood battle rule among Upper Moons dictates that strength determines position. Since he believes in power above all else, it's only natural that sufficient strength should allow us to replace him."
Oboro felt genuine satisfaction at this response, though he wasn't surprised. Doma's betrayal stemmed from his twisted fascination with immortality and, more specifically, with Oboro himself. This perverted demon was utterly captivated by Oboro, recognizing that remaining loyal to Muzan would likely result in death and eliminate any future opportunities for interaction.
Doma understood Oboro's impact on this world perfectly. While ordinary people, such as the Ubuyashiki clan and the Demon Slayer Corps, viewed Oboro as disturbed—a twisted mind that derived pleasure from death and chaos—this perspective resonated deeply with Doma's own nature. He saw Oboro as a kindred spirit: a being who transcended humanity's rotting morality and mundane emotional attachments.
Unlike Muzan, who, despite being the progenitor of demons, still succumbed to anger, lost control over trivial matters, and displayed the same "foolish" emotional patterns as humans, Oboro represented something purer in Doma's twisted worldview.
Kokushibo's motivations ran deeper, rooted in the profound emptiness that had consumed him since his human days. His eternal obsession with surpassing his younger brother, Yoriichi Tsugikuni, remained undiminished, even after losing his human memories. That burning desire and obsession had carved itself permanently into the depths of his soul.
The symbol of Yoriichi's overwhelming power was forever etched in Kokushibo's consciousness. Even as one of the Upper Moons, he felt pathetically weak compared to his deceased brother's legendary strength. Kokushibo refused to accept his limitations; he would surpass Yoriichi, no matter the cost.
He had originally decided to follow Muzan because of the Demon King's promise of demonic power. Now, he betrayed that same master for the same reason: to seek even greater strength from Oboro.
The tragic irony remained inescapable: Kokushibo would never truly surpass the long-dead Yoriichi. Even if he acquired power that substantially exceeded his brother's, he would still consider himself inadequate. He was destined to remain a perpetual loser, trapped by his own psychological limitations.
"Very well. I'll satisfy your desires."
Oboro extended his finger, allowing a single drop of blood to form at the tip.
"I believe what happens next will prove quite exciting."
The unexpected arrival of the two Upper Moons had simplified his plans considerably. Now, Muzan the Demon King would come to him, so he wouldn't need to actively hunt him down.
Within the Infinity Castle, Muzan stood motionless on a floating platform. His expression was carefully controlled, but his eyes radiated deadly coldness. The dense network of veins and blood vessels visible across his face betrayed his barely contained fury.
He had learned of Doma and Kokushibo's treachery.
The two remaining Upper Moons knelt on the platform below, not daring to breathe audibly. Hantengu trembled in terror, and the newly appointed Upper Moon Six sweated profusely beside him.
Two of the original six Upper Moons had betrayed him, and one was dead. Yesterday, another newly promoted Upper Moon Six fell to two Hashira of the Demon Slayer Corps. Currently, aside from Nakime, who controlled the castle itself, only these two demons remained under his command.
These losses were the heaviest Muzan had suffered since becoming the Demon King and acquiring his enhanced powers. Even during the most intense three-way battles between Muzan, the Demon Slayer Corps, and the successors, only the Lower Moons were completely eliminated, while the Upper Moons remained largely intact.
Gyokko's consumption by Gyutaro was already a serious blow to Muzan.
"Since when have even the Upper Moons become so utterly useless?"
The oppressive atmosphere in the Infinity Castle grew suffocating as Muzan spoke with icy indifference.
Hantengu clutched his head, his entire body shaking as he wept continuously. The Upper Moon Six beside him watched sweat steadily drip onto the platform.
Muzan's immediate instinct was to kill the remaining two Upper Moons to vent his rage, but rational calculation prevented him from doing so. Despite their apparent uselessness, both demons had sufficient talent to reach their current positions. Training new demons to the level of the Upper Moons required significant time, energy, and favorable circumstances, which were hardly realistic in the short term.
The situation with the Lower Moons was even more problematic. Recently, the replacement rate had become absurdly high. Only after Muzan personally infused new blood into the Lower Moons did they grow strong enough to avoid immediate destruction by the Hashira.
"I will kill them both myself."
After a prolonged silence, the new Upper Moon Six gathered his courage and stammered out his offer, referring to Doma and Kokushibo.
"You?" Muzan's eyes narrowed dangerously.
The demon was clearly lying, terrified of being killed for angering his master. The idea of an Upper Moon Six challenging two higher-ranked demons was laughable. Doma alone could destroy him effortlessly. The power gap between their respective eras was insurmountable.
Muzan's expression suddenly shifted to a cold smile. "Excellent. I'll give you that opportunity.
"Let's see if you can actually accomplish such a feat."
At his signal, Nakime struck her biwa. Instantly, every door and gate throughout the Infinity Castle began to open and close rapidly, exchanging positions as rooms and platforms rotated chaotically through dimensional space.
"Betray me?" Muzan murmured to himself.
Such defiance was absolutely intolerable. He could guess at Doma and Kokushibo's motivations; they believed he would lose the upcoming conflict. Regardless of their reasoning, neither traitor would escape their fate.
Nakime's Infinity Castle would inevitably draw them in. This separate dimensional space was completely inaccessible to uninvited guests, so Oboro posed no immediate threat to Muzan there.
Even if Doma and Kokushibo had encountered Oboro, what difference would it make?
As the castle's spatial configuration transformed, two familiar figures appeared on platforms on either side of Hantengu and Upper Moon Six.
Kokushibo appeared in his traditional samurai attire, and Doma wore his religious founder's robes and held an iron fan.
"Ah, this familiar atmosphere is truly nostalgic," Doma said, spreading his arms wide and sighing with apparent pleasure. "Every visit here fills me with such inexplicable joy."
"Perhaps it's because coming here guarantees I'll meet you, Lord Muzan." Doma's rainbow-colored eyes turned toward the figure above, radiating murderous intent.
Despite facing the extremely dangerous Muzan, Doma's expression remained completely unchanged, showing no trace of fear. He appeared exactly as he had when he served as Muzan's loyal subordinate, as if no betrayal had occurred.
BANG!
Without warning, Doma's head exploded, showering the platform with blood and bone fragments.
Muzan hadn't even bothered with questions before executing his former subordinate. His gaze shifted to the silent Kokushibo before addressing the terrified Upper Moon Six.
"Didn't you claim you would eliminate the traitors? There's still one remaining. Proceed."
Upper Moon Six's pupils dilated in terror as he stared at Kokushibo. Upper Moon One, the strongest demon after Muzan!
"What's wrong?" Muzan asked with false innocence.
"I, I—"
Upper Moon Six slowly rose to his feet, drenched in sweat.
How could he possibly challenge Upper Moon One? Either Kokushibo would kill him or Muzan would execute him for being a coward. There was no possibility of survival.
"He's going to die!" The demon's despair was absolute.
"I'd advise taking action quickly," a familiar voice suddenly interrupted, laced with dark amusement. "Being killed by Upper Moon One, well, the former Upper Moon One, isn't particularly painful. But if you anger Muzan, based on what I know, you'll likely endure excruciating torture before death."
"Or perhaps you prefer being tortured? Do you consider it a reward?"
Without warning, that familiar laugh echoed through the castle.
Muzan's carefully controlled expression cracked as his pupils contracted in shock. He spun toward Doma's body and watched in disbelief as the demon regenerated a new head and stood upright.
Complete stunned silence.
Muzan could feel the power of souls granting him enhanced cellular control. With a mere thought, he could prevent any Upper Moon from regenerating, causing their flesh and blood to turn against them.
He didn't need to take direct action; he could simply will Doma's cells to cease functioning permanently.
Yet somehow, impossibly, Doma had returned to life!
"Lord Muzan, your expression at this moment is absolutely delicious," Doma said, deliberately twisting his newly grown head left and right to test its mobility. His tone became unnaturally strange as he stared directly at his former master. "Surprised? You should be quite familiar with the sensation of losing control, just as when the Inheritor first appeared."
"The power you acquired and the secrets you learned, I possess as well."
You should be celebrating for me."
Doma's smile blazed with twisted satisfaction.
Muzan's features contorted with rage, and he unleashed his soul power instinctively, generating a crushing mental pressure that spread throughout the castle in invisible waves.
Everything touched by this psychic tide seemed frozen in time and space. Upper Moon Six immediately collapsed unconscious, and Hantengu transformed into a statue. Even Nakime dropped her biwa and hugged herself, trembling uncontrollably.
But Doma and Kokushibo remained completely unaffected.
"It's useless. Give up," Kokushibo stated in his deep, measured voice.
Muzan's eyes trembled as the impossible reality crashed over him. How could this be happening?
"Though I'm not a woman, adding you to my collection would certainly be the happiest moment of my existence, Lord Muzan. It would be truly special beyond measure," Doma added with perverse enthusiasm.
"You dare!" Muzan's fury exploded.
Had two worthless pieces of trash, who only survived through his charity, dared to speak to him this way?
"Oh? Are you angry?" Doma's tone remained mockingly pleasant. "But before you decide how to deal with us, you should probably welcome your guest."
He's been waiting patiently for quite some time."
Doma raised his eyebrows and chuckled in a sinister way.
"What?" Muzan's senses suddenly detected an impossible presence. His heart lurched as he began to turn in the indicated direction.
The soft rustling of fabric reached his ears, clothes shifting in movement.
Through his peripheral vision, Muzan caught sight of a black haori that he recognized with terrifying familiarity.
A figure materialized beside him like a specter, appearing with ghostly silence.
Though he had never seen Oboro directly, that iconic coat was unmistakable.
It was him!
He was here!
Muzan's mind went completely blank. This development was beyond anything he had calculated.
How had he entered the Infinity Castle?
"We finally meet, Muzan Kibutsuji."
The soft tap of wooden geta sandals against the platform floor echoed ominously as Oboro spoke from directly beside him.
Muzan's hands and feet went numb, and he stumbled backward several stiff steps to create distance from the newcomer. He swallowed hard; his throat was suddenly dry.
"Originally, locating you would have required considerable time. After all, your caution is quite remarkable. But I never expected these two to come seeking me out, accelerating our inevitable meeting."
Muzan stared at the white-haired elder before him, who was smiling peacefully and leaning on a wooden staff. His expression radiated calm serenity.
The Demon King found himself unable to speak, as if he had lost the ability entirely.
Oboro observed Muzan's defensive posture, his ancient eyes gleaming with deep understanding.
"Do you want to escape?"