On the third night, shortly after sunset, Kokushibo and his companions finally arrived at the residence of Rengoku Shinjuro.
As before, Kokushibo maintained the guise of a blind swordsman, his demonic features carefully concealed.
Shinjuro welcomed them with his usual booming enthusiasm so loud that it made Yushiro visibly uncomfortable.
Still, faced with the overwhelming presence of a former Hashira, Yushiro held his tongue.
Upon hearing that Kokushibo had returned with a physician, Kyojuro Rengoku immediately brought his younger brother, Senjuro Rengoku, into the living room.
"Father!" Kyojuro bowed deeply. Then, turning to Kokushibo, he added with equal respect, "Adoptive Father!"
Kokushibo regarded him briefly, then motioned for him to come closer, resting a hand lightly on his shoulder.
"This is the physician," he said, gesturing toward Tamayo. "She will examine your mother."
He deliberately added, with faint amusement,
"You may address her respectfully."
Kyojuro, ever earnest, nodded immediately.
"Thank you for coming. Please… you must save my mother!"
Yushiro stiffened, irritation flashing across his face.
"…Show some respect," he muttered under his breath. "Lady Tamayo is "
Tamayo raised a hand slightly, stopping him before he could continue.
"It is fine."
She stepped forward, her expression calm and professional.
"May I examine her condition?"
"Of course," Shinjuro replied at once.
Kyojuro quickly led the way toward the bedroom.
Yushiro moved to follow, but Kokushibo's hand stopped him mid-step.
"What are you doing?" Yushiro snapped quietly.
"It would be inappropriate," Kokushibo replied evenly, "for you to enter uninvited."
Yushiro clenched his fists but ultimately relented, forced to remain behind.
Thus, Tamayo and Shinjuro entered the bedroom, leaving Kokushibo seated calmly on the tatami in the living room.
Around him sat an uneasy trio:
Kyojuro, Senjuro, and Yushiro.
The tension was… palpable.
After a moment, Kokushibo spoke, his tone casual.
"You have been with Tamayo for only a few years," he said, glancing toward Yushiro. "Yet your devotion is absolute."
Yushiro initially ignored him.
But at the mention of Tamayo, his expression shifted.
"It has nothing to do with time," he replied firmly. "Lady Tamayo saved my life. That is enough."
Kokushibo leaned slightly closer.
"…You care for her."
Yushiro froze.
"I "
The words caught in his throat. Realizing too late what he had revealed, he turned away sharply.
Kokushibo said nothing further, though the faint curve of his lips spoke volumes.
Nearby, Kyojuro sat quietly with Senjuro, unable to follow the conversation, yet maintaining an unwavering smile hopeful, patient.
Inside the bedroom, Tamayo conducted her examination.
Ruka Rengoku lay resting against her bedding, her breathing shallow, her complexion pale.
Shinjuro stood nearby, unable to conceal his concern.
Tamayo worked methodically observing, questioning, listening.
Her demeanor remained composed throughout.
After a preliminary assessment, she spoke gently.
"I will need to conduct a more thorough examination. May I ask you to step outside for a moment?"
Shinjuro hesitated.
Then, at Ruka's quiet nod, he complied.
As he stepped into the living room, Kokushibo tilted his head slightly.
"…It seems you were asked to leave."
Shinjuro exhaled, a hint of awkwardness crossing his face.
"It is necessary," he said simply.
He began preparing tea for his guests.
Kokushibo accepted a cup and, with deliberate mischief, passed it toward Yushiro.
"Careful," he said lightly. "It may contain wisteria."
Yushiro nearly dropped it.
"…You !"
Before he could react further, Shinjuro laughed.
"It is ordinary tea. Wisteria is used against demons, yes but it is not something one would serve as a drink."
Yushiro relaxed slightly, though his glare toward Kokushibo remained.
Time passed slowly.
Kyojuro finally spoke, unable to contain himself.
"…Will Mother recover?"
Before Kokushibo could answer, Yushiro replied bluntly,
"If Lady Tamayo has taken the case, then there is hope."
Kyojuro nodded, holding onto those words.
Kokushibo said nothing, though he did not contradict him.
At last, the door slid open.
Tamayo emerged.
Shinjuro and his sons immediately gathered around her.
"What is her condition?" Shinjuro asked.
Tamayo spoke clearly, her tone measured.
"The illness has progressed over many years. It resembles what is known as a chronic pulmonary disease what some physicians might call tuberculosis."
Kokushibo's gaze sharpened slightly.
So that was it.
In this era, such an illness would indeed be considered nearly incurable.
Tamayo continued,
"However… it is not beyond treatment."
Hope surged instantly.
"But," she added, "I did not anticipate this specific condition. The necessary medicines are not with me, and some will be difficult to obtain."
Shinjuro's expression dimmed but only slightly.
Hope remained.
"As long as there is a chance," he said, "that is enough."
Tamayo inclined her head.
That night, despite Shinjuro's insistence, Tamayo declined to stay.
Under the cover of darkness, Kokushibo, Tamayo, and Yushiro departed.
The Rengoku family stood at the entrance, watching until their figures vanished into the night.
On the road, silence lingered for some time.
At last, Tamayo spoke.
"…Why?"
Kokushibo did not respond immediately.
"You have no reason to aid a Hashira," she continued. "Nor to involve yourself with his family."
Her gaze was steady.
"This is not about Flame Breathing. Nor that child."
She paused.
"You act with purpose."
Kokushibo exhaled softly.
"…And you concern yourself with my intentions, even now."
Tamayo did not deny it.
He continued,
"You are correct. I have no interest in Flame Breathing itself."
His voice lowered slightly.
"My enemy is not limited to Muzan… nor to the Demon Slayer Corps."
The air grew still.
"For some time now," he said quietly, "I have felt it."
A presence.
Unseen.
Unfathomable.
"…Something is watching."