Tamayo's Arrival

Life is like the gently flowing stream in the Butterfly Mansion courtyard, moving forward calmly and regularly.

Moyu maintained his cultivation rhythm. Every morning, before the first rays of sunlight had completely dispelled the darkness, he would already be sitting in the secluded Valley behind the mountain, practicing Advanced Mental Strength Meditation Method.

The process of meditation is both cultivation and adaptation. He could clearly perceive that his Mental Energy was like a piece of iron being repeatedly forged, becoming more and more resilient and solid under the impact of the information flow. He understood that when his Mental Energy was strong enough to process all the information received by the Six Eyes without any burden, this cloth strip could be removed.

During the day, aside from necessary cultivation, he would occasionally stroll around the Butterfly Mansion. Although blindfolded, the world unfolded in another form in his six-eyed perception: the flow of energy outlined the contours of all things, the rhythm of life was like a spectrum of different frequencies, and even the trajectory of petals drifting in the wind was clearly visible. This unique vision allowed him to move as usual, even more comprehensively than when he saw with his eyes.

"Mr. Moyu!"

One afternoon, Mitsuri Kanroji's cheerful voice came from the entrance of the courtyard. She was carrying a small bamboo basket, and her pinkish-green eyes curved into crescents when she saw Moyu sitting quietly under the eaves.

"Oh my, Mitsuri's here." Shinobu Kocho peeked out from the pharmacy, holding a pestle in her hand, a gentle smile on her face.

Moyu tilted his head slightly, looked in Mitsuri's direction, and nodded gently.

Mitsuri trotted over and sat down next to Moyu, proudly opening her basket. "Look, look! I tried making sakura mochi today! The kind with lots of red bean paste! Miss Shinobu, Mr. Moyu, please try some!"

The basket was neatly filled with pink cherry blossom mochi, their translucent skins revealing glimpses of the deep red bean paste filling inside, and emitting a faint cherry blossom fragrance.

Shinobu Kocho washed her hands and came over, picked one up and tasted it, her eyes lighting up slightly. "Mmm~ the sweetness is just right, and the outer skin is very soft and chewy. Mitsuri's skills are getting better and better."

Moyu picked one up and slowly took a bite. The sweet red bean paste melted in his mouth, mixed with the faint fragrance of cherry blossom leaves. After swallowing, he simply commented, "Not bad."

"Really? That's great!" Mitsuri clapped her hands happily, then remembered something and pulled out a small bow woven with colorful threads from her pocket. "Oh right, this is for Nezuko- chan! I can put it on her when she wakes up!"

Mentioning Nezuko, Mitsuri started talking non-stop. "Nezuko- chan is so cute... By the way, Mr. Moyu, when will your eyes get better? Even though you look cool blindfolded..."

She chattered on about everyday trivia, her tone light and cheerful, brimming with the innocence and enthusiasm unique to young girls. Shinobu Kocho occasionally chimed in, and the two talked about the Butterfly Mansion's recent developments, the team members' training progress, and even the latest fabric patterns in town. Moyu mostly listened quietly, offering brief responses only occasionally, creating a warm and relaxed atmosphere.

Such afternoons were common at the Butterfly Mansion. Sometimes Mitsuri would bring snacks, and sometimes Shinobu Kocho would brew new flower tea. The three of them would sit on the veranda, watching the Wisteria and fade in the courtyard, chatting about trivial everyday matters. Although Moyu a man of few words, his attentive manner was reassuring.

At dusk, after Mitsuri returns home, Moyu will end his day's cultivation.

As the last rays of the setting sun disappear below the horizon and night falls over the courtyard, a small figure will come running out of the house with a "thump, thump, thump".

"Mmm!"

Nezuko, dressed in a pink kimono and barefoot, skipped and twirled joyfully in the moonlit courtyard. She couldn't be exposed to sunlight, so nighttime was when she was most active. Moyu would sit on the veranda, watching her chase fireflies in the yard, or squat by the pond, curiously "watching" the fish swimming in the water; her focused expression was exceptionally adorable.

Sometimes Nezuko would run to Moyu's side, tilting her little face up and making "ooh ooh" sounds, carefully showing him the fireflies she had caught. Moyu would reach out and gently touch her soft hair, or take the smooth pebbles she handed him, which he had picked up from somewhere. Nezuko seemed to be able to sense the calm yet powerful aura emanating from Moyu, and she was exceptionally quiet and obedient when she was around him, blinking her big pink eyes. Occasionally, she would sit down next to his legs and curl up into a small ball.

Shinobu Kocho would join them at this time. She would bring warm herbal tea and share it with Moyu, while she herself would hold a teacup and watch Nezuko play in the courtyard, her purple eyes filled with a gentle smile.

"Nezuko looks very energetic today," Shinobu said softly.

"Hmm." Moyu responded, the steam from the teacup in his hand displaying a unique energy outline in the perception of the Six Eyes.

Such nights are peaceful and serene, as if the cruelty of fighting demons has temporarily faded away. Nezuko's innocent and carefree demeanor always envelops the Butterfly Mansion in a warm glow.

Days passed by like this. Moyu's cultivation progressed steadily, his Mental Energy grew slowly but surely through continuous meditation, and his adaptation to the six eyes improved more and more.

Until one seemingly ordinary night.

Moyu had just finished a round of deep meditation and was sitting on the tatami in his room, slowly adjusting his breathing. In the courtyard, Nezuko had finished playing and was being taken back to her room to rest by Shinobu. Most of the Butterfly Mansion was dark, except for the pharmacy and Shinobu Kocho's room, which still had a faint light on.

Just then--

Suddenly, at the edge of his six eyes' perception, he detected two extremely subtle yet strangely familiar energy fluctuations.

The aura of a ghost.

Moreover, these were not ordinary ghosts. Of the two auras, one was calm and profound, bearing strong traces of drug and blood research; the other was wary and sharp, filled with protective hostility.

Tamayo, Yushiro.

Moyu's brow twitched almost imperceptibly.

Moyu stood up, his "gaze" beneath the black cloth bandage directed towards the Ubuyashiki. The two ghostly auras were cleverly concealed by some kind of power, probably Yushiro's Blood Demon Art, but it couldn't fool the Six-Eyed. He could see that Kagaya Ubuyashiki's aura was steady, and he was not surprised by the arrival of these two uninvited guests.

After a moment's hesitation, Moyu pushed open the door, his figure silently disappearing into the night. He didn't disturb anyone, including Shinobu Kocho in the next room. Azure energy condensed into an imperceptible vortex beneath his feet, and in the next instant, he was already dozens of feet away, speeding towards the Ubuyashiki.

The Ubuyashiki residence quickly came into view. The two ghostly auras were inside the main house, very close to Kagaya Ubuyashiki's aura.

Space distorted slightly, and "Cang" activated his teleportation. His figure appeared in the shadows of the main hallway without making a sound.

Voices could be heard coming from inside the house.

"... Thank you for coming, Ms. Tamayo." It was Kagaya Ubuyashiki's gentle but weak voice.

"It is I who should thank you, Ubuyashiki." A calm and gentle female voice rang out; it was Tamayo. "Thank you for trusting a 'demon' like me and for providing such a safe and secluded meeting place."

"Trust is mutual, Ms. Tamayo," Ubuyashiki said gently.

Tamayo's voice turned serious, "After long-term research, and with the blood samples of the Twelve Kizuki sent by Mr. Moyu, I have successfully developed four kinds of potions."

Moyu listened quietly in the shadows of the corridor, his six eyes clearly seeing the scene inside the room: Kagaya Ubuyashiki was half-lying on the tatami, his face wrapped in bandages, his breath weak but steady. His wife, Amane Ubuyashiki, was kneeling beside him. Opposite him was Tamayo, dressed in a kimono with a gentle demeanor, and Yushiro, who stood behind her like a guard, his face full of vigilance.

Tamayo took out four small glass bottles from her medicine box, each containing a liquid of a different color.

"The first one," she picked up a bottle containing a pale golden liquid, "Is a medicine that turns ghosts back into humans. I've completed theoretical verification and preliminary live experiments, confirming its effectiveness. It takes time for the medicine to take effect, but it can ultimately reverse the ghost transformation."

Kagaya Ubuyashiki leaned forward slightly. "So, it's for Nezuko Kamado..."

"Yes," Tamayo nodded. "I already knew about Tanjiro and Nezuko's situation when I was in Asakusa. Nezuko has never eaten anyone and has a strong will, so her body should have a much smaller reaction to the medicine. This medicine can be given to her."

"The second one," Tamayo picked up the second bottle, which contained a deep purple, viscous liquid, "Is an Aging potion. It can greatly accelerate the cell division of demons, causing them to Aging rapidly and become weak. It's specifically designed to counter the regenerative abilities of demons."

"The third type," the last bottle contained a bright red liquid that rippled slightly as if it were alive, "Is poison. Developed specifically for Muzan Kibutsuji's unique constitution, it combines multiple ingredients that Regeneration Suppression and destroy cell structure. Once injected into his body, it will disintegrate him from the inside. Combined with the Aging agent, it forms a deadly synergy; the faster his cells divide, the faster they are destroyed, creating a vicious cycle."

"The fourth type is a regeneration-inhibiting drug. When Muzan faces a Muzan situation, he can split himself into countless fragments to escape. As long as one fragment survives, he can regenerate. This drug specifically prevents the regeneration and fusion of these fragments."

Tamayo placed the four bottles on the tatami mat and solemnly said, "My suggestion is that during the final battle, we combine several of these potions and infuse them into Muzan's body..." She looked at the bottles on the ground, "Significantly weakening him and dragging the battle out until dawn might completely end the curse."

A brief silence fell over the room. Kagaya Ubuyashiki seemed to be deep in thought.

Just then, Moyu pushed open the shoji door in the corridor.

"Who?!" Yushiro instantly stepped in front of Tamayo, his pupils contracting and sharp fingernails extending.

Tamayo was slightly taken aback, but when she saw the person clearly—his distinctive white hair and calm yet vast aura—she immediately recognized him. "Mr. Moyu."

Kagaya Ubuyashiki wasn't surprised; instead, he smiled knowingly. "Moyu, you noticed after all. Please come in."

Moyu entered the house and sat down next to Tamayo, facing Ubuyashiki. "I sensed their presence, so I came to check on them."

His tone was indifferent, as if he were just casually visiting. But Yushiro's vigilance did not relax at all. He stared intently at Moyu, especially at the eyes covered by a black cloth, instinctively feeling a great threat.

"Mr. Moyu has arrived at just the right time," Ubuyashiki said gently. "Tamayo has brought crucial research findings. What are your thoughts on the final battle?"

Moyu glanced at the four medicine bottles, his gaze lingering for a moment, especially on the pale gold Demon Transformation Medicine.

"The medicine is very good," he said bluntly, "But it might not be necessary for Muzan."

Ubuyashiki and Tamayo both looked at him.

"With my current strength, I am more than capable of dealing with Muzan and the other Upper Rank Demons." Moyu's voice was completely calm, simply stating a fact.

Ubuyashiki was silent for a moment, then slowly said, "I believe in Moyu- kun's strength. But Muzan has lived for a thousand years, is cunning and suspicious, and has countless ways to protect himself. The more prepared we are, the greater our chances of winning. The development of this drug is not only to add another way to kill him, but also to prevent any unforeseen circumstances..."

Moyu said no more. He understood Ubuyashiki's considerations. As the Oyakata-sama of the Demon Slayer Corps, he had to consider all possibilities and be responsible for the entire organization and for ending the thousand-year curse. The existence of the medicine provided an extra layer of protection.

"That works too." Moyu nodded.

Just then, footsteps sounded again outside the door.

"My Master, you wanted to see me—" Shinobu Kocho's voice rang out as the shoji door opened, then abruptly stopped.

Her purple eyes froze instantly, and the usual gentle smile on her face stiffened. Her gaze was fixed on Tamayo and Yushiro inside the room, those two beings emanating a distinct ghostly aura.

Almost instinctively, Shinobu's hand rested on the hilt of her Nichirin Blade. A chilling, sharp killing intent emanated from her petite frame. It was the instinct of a Pillar who had endured countless battles and harbored an extreme hatred for demons.

"Please be patient," Kagaya Ubuyashiki said calmly. "Please come in and close the door."

Shinobu Kocho's fingertips turned slightly white on the hilt of her sword. She took a deep breath, forced herself to release her grip, went inside, closed the door, and knelt down beside Moyu. But her gaze never left Tamayo and Yushiro, her purple eyes churning with complex emotions: astonishment, wariness, and a hint of suppressed, deep anger.

"These two are Miss Tamayo and Mr. Yushiro," Ubuyashiki introduced gently. "Miss Tamayo is a special demon. She has long since broken free from Muzan's control and has dedicated herself to developing a drug to destroy Muzan and turn demons back into humans for hundreds of years. She has come today to provide crucial research results."

He briefly summarized Tamayo's introduction and the effects of the four medicines.

Shinobu Kocho listened quietly, a smile returning to her face, but it was more formulaic and... colder than usual. Her gaze swept over the four medicine bottles, and her eyes flickered slightly when she heard that the "Demon Transformation Medicine" was effective on Nezuko.

But when she looked at Tamayo again, that cold scrutiny did not melt away in the slightest.

"I see." Shinobu's voice was soft and sweet, yet carried a hint of distance. "Ms. Tamayo's research is truly admirable. I am also sincerely grateful to Nezuko."

She paused, her purple eyes fixed on Tamayo: "But, Miss Tamayo, you were once... also Muzan's subordinate, and you also ate people, right?"

The air froze instantly.

Yushiro's eyes flashed with anger, but Tamayo gently stopped him with a raised hand.

Tamayo met Shinobu's gaze calmly, her serene eyes filled with deep guilt and sorrow. "Yes. It is an undeniable and irreparable sin. Even though I have long since broken free from Muzan, I cannot erase the past that consumed innocent lives. I... do not ask for forgiveness."

Her voice was calm, yet heavy as if soaked in blood.

Shinobu Kocho's smile remained unchanged, but Moyu could clearly sense the violent fluctuations in the energy within her body. It wasn't just anger, but also pain, struggle, and a deep-seated hatred. Tamayo's identity as a "demon" and her history of cannibalism touched Shinobu's deepest wounds.

For Shinobu, Nezuko was a special exception, a miracle of "never eating people," and a sister-like figure she was willing to protect with her life. But Tamayo was different. No matter how friendly she appeared or how much she contributed, her past was like an insurmountable chasm, standing between Shinobu's reason and emotions.

Rationally, Shinobu understood Tamayo's value, the importance of cooperation, and her Oyakata-sama's considerations.

But emotionally... deep within those violet eyes surged a deep-seated hatred and absolute rejection of the existence of "ghosts".

"I understand," Shinobu finally said softly, her tone returning to its usual gentleness, but beneath that gentleness lay an icy aloofness. "To eliminate Muzan, I will cooperate. If assistance is needed in the subsequent research and preparation of the drug, I will do my best."

She didn't use the word "cooperate," but rather "coordinate." Every word she chose conveyed a sense of distance.

Kagaya Ubuyashiki looked at Shinobu, a flicker of understanding and tenderness crossing his eyes. He understood each of the Pillars, and he understood Shinobu's inner wounds. He didn't press the matter, but simply said gently, "Thank you for your hard work, Shinobu. We can discuss the specific details later."

Tamayo nodded slightly, making no attempt to close the distance. She understood this barrier, a barrier stemming from her own sins, which she could neither resolve nor hoped to resolve.

The meeting continued for a while. Shinobu Kocho listened quietly throughout, only responding briefly when asked questions. Her gaze mostly lingered on the pattern of the tatami mat, or occasionally glanced at Moyu. It seemed that being near him calmed her cold and sharp emotions somewhat.

By the time the discussions came to an end, it was already late at night.

"Well then, Ms. Tamayo, Mr. Yushiro, please rest in the guest rooms provided. We'll finalize the follow-up plans tomorrow," Ubuyashiki said, his voice already sounding tired.

Tamayo and Yushiro bowed and took their leave, guided by the members of the Hidden Team. As they walked down the corridor, Yushiro turned back and glared fiercely at Moyu and Shinobu Kocho, especially Shinobu, whose eyes were full of warning.

Only the Ubuyashiki couple, Moyu, and Shinobu Kocho remained inside.

The atmosphere was somewhat somber.

"My Master," Moyu suddenly spoke, "Let me check on your health."

Ubuyashiki slightly, then smiled and said, "It's an old problem, no need..."

Moyu had already stood up and walked to his bedside. He raised his hand, hovering it over the chest of the Ubuyashiki, a soft white light emanating from his palm.

Amane Ubuyashiki watched nervously, but did not stop him. She knew that Moyu's abilities were extraordinary.

Energy slowly seeped into the Ubuyashiki's body. Moyu's six eyes clearly "saw" the cold and filthy curse power that was wrapped deep within the Ubuyashiki's bloodline. It was a Muzan curse originating from Muzan against the Ubuyashiki Clan, which continued with the existence of the Demon King and could not be eradicated.

Moyu did not attempt to touch the curse, as it involved deeper rules and causality, which he could not yet break with his current understanding of reversal techniques. But what he could do was restore some of Ubuyashiki's own life force.

Warm energy, like the spring sun, flowed through his organs, which had withered and weakened by the curse, nourishing every failing meridian and replenishing the vitality constantly consumed by illness. Ubuyashiki felt a long-lost warmth spread from his chest throughout his body, and the ever-present heaviness and suffocation seemed... to have lessened somewhat. Although the curse remained and his body was still weak, the flame of life that seemed on the verge of being extinguished at any moment had become much more stable and bright.

After a long while, Moyu withdrew his hand, and Ubuyashiki slowly sat up straighter, moving his arms in surprise and taking a few deep breaths. "I feel... much more relaxed. Moyu- kun, this is..."

"A temporary relief," Moyu said calmly. "I can't break the curse, but your body can be strengthened. At least, you can stay conscious until the final battle."

Kagaya Ubuyashiki was stunned. He stared at the white-haired, black-banded young man before him, whose veiled eyes seemed to see through everything, including the short and painful fate that Kagaya had long since accepted. This sudden act of saving his life stirred up complex emotions within him.

"Thank you," he finally said solemnly, his voice trembling slightly.

Amane Ubuyashiki lowered her head deeply, her shoulders trembling slightly.

"I should go back too." Moyu turned around and walked towards the door.

"Moyu- kun," Shinobu Kocho called softly, and followed him.

The two walked one after the other back to the Butterfly Mansion. The night was deep, and the starlight was dim. The chirping of insects rose and fell in the grass.

Ren silently walked half a step to Moyu's side. After a long while, she finally spoke softly, her voice barely audible in the night breeze. "You already knew about Tamayo."

"Mm," Moyu replied.

"Why... why didn't you tell me?" Shinobu's voice was devoid of emotion.

"There's no need," Moyu said. "Whether you know or not won't affect her research or the results. It will only make you feel bad sooner."

Ren paused for a moment.

"... Just now, I was very angry," she admitted, her voice low. "Seeing her reminded me of my sister... and all the people who were eaten by ghosts. I know she's different, I know she was helping, but..."

"Don't force yourself to accept it," Moyu interrupted her, his tone calm. "Just do what you're supposed to do. Your feelings don't need to be sacrificed for the greater good."

Shinobu Kocho raised her head and looked at Moyu's blindfolded profile. In the moonlight, his outline appeared somewhat blurry, yet incredibly clear.

The knot of unease in my heart seemed to have been somewhat dispersed by the night breeze.

"Mmm." She responded softly, a genuine, faint smile returning to her face. "Let's go back quickly. It wouldn't be good if Nezuko woke up in the middle of the night and couldn't find anyone."

She was sleeping soundly.

"Really? Moyu- jun can even 'see' this~"

"Um."

The sound of their footsteps gradually faded into the night, disappearing into the direction of the Butterfly Mansion.