"Why?! Why is it that I set out first, yet you still arrived before me, big brother?!"
Hiru puffed his cheeks, trudging behind Yoriichi with his box on his back. "Don't tell me your physical abilities haven't declined at all! You were holding back during our last race, weren't you?! I'm mad! Really mad!"
"Hmm, because there's something I want you to agree to," Yoriichi slowed his pace and, as always, reached out to gently ruffle Hiru's hair. "And you already agreed, didn't you?"
Hiru pouted. "You're so sneaky, big brother... If you're about to say something like, 'Keep living as a demon and help humans,' forget it. I'm not as kind as you. When I see people even worse than demons, all I can think is—maybe it's better to just destroy this world.
After all, without humans, demons would eventually die out too. And nature is way more beautiful than any city."
Yoriichi simply ruffled his hair again before withdrawing his hand. "You mentioned Miss Tamayo was in Nara?"
"Yeah. The mark points that way," Hiru replied, following closely behind. "Too bad it's the end of the year—no merchant caravans around. It would've saved us a lot of trouble to travel with one."
"It's fine. Think of it as training."
"Who even wants that kind of training..."
Despite his grumbling, Hiru still obediently followed Yoriichi on foot toward Nara.
Traveling with Hiru brought Yoriichi both joy and mild frustration. During this journey, for instance, he discovered a trait he'd somehow missed for decades—Hiru was easily distracted by anything beautiful or unusual. Once his attention wandered, he'd stray off course and get lost, all without realizing it.
Because of that, what should have been a month-and-a-half journey stretched into three. For at least two of those months, Yoriichi would suddenly notice Hiru wandering off, but couldn't bring himself to call him back right away—he'd simply wait until Hiru noticed on his own before correcting their path.
...
When they finally reached Tamayo in early spring, she was visibly astonished.
"Mr. Yoriichi, Mr. Hiru—it's been such a long time."
Though decades had passed, Tamayo remained stunningly beautiful. Dressed in a pale kimono, her violet eyes still carried that faint, sorrowful air—only now, they also held a trace of confusion.
"I've come to ask a favor, Miss Tamayo," Hiru began.
"Please, go ahead."
"I want you to create a drug that can kill me."
Tamayo froze. "...I'm sorry—what did you just say?"
"Actually, about three months ago, I tried to kill myself by stepping into the sunlight," Hiru said with a sigh, opening his hands. "But as you can see... I'm still alive."
Tamayo's pupils contracted sharply, her voice trembling. "You... you mean you've overcome sunlight?"
Hiru nodded slightly. "As you know, Miss Tamayo, I've spent years developing a medicine to restore my humanity. But the results... haven't been very good.
And those attempts seem to have made me slightly... resistant to Wisteria."
Tamayo turned to Yoriichi, her expression tightening. "Then... even you, Mr. Yoriichi, can't end him?"
Hearing that, Yoriichi—who had been quietly observing the room—lifted his gaze and shook his head. "I don't know."
Her confusion deepened. "...May I ask why?"
"I no longer have the courage to face Hiru's death a second time," Yoriichi said calmly, his words breaking through Tamayo's composure. "Even if he's now immune to Wisteria and sunlight, I still wish for him to live."
"That's why," Hiru added evenly, "I want you to make that drug before my brother dies. Because I'm not sure I'll have the courage to follow him if he goes before me."
Tamayo fell silent for a long moment, looking between the two equally calm men. Finally, she nodded. "I understand. I'll do my best. For now, please stay here."
...
Later, Tamayo drew a vial of Hiru's blood and began experimenting to neutralize its vitality. Outwardly, her clinic claimed to have closed temporarily to treat a critically ill patient.
She tested several of her anti-demon poisons on Hiru, but none had any effect. He even remarked that one of them tasted sweet. After asking her about the ingredients, he took the recipe to Yoriichi, who was practicing swordsmanship, and persuaded him to make strawberry daifuku using rice flour mixed with the medicine.
Hiru then happily devoured more than ten of them with pure joy on his face. He said that, though the taste was strange, being able to experience a flavor other than blood for the first time since becoming a demon deeply moved him.
...
Half a month later, while Tamayo was still buried in her research, Yoriichi came to her alone.
"Is there something you need, Mr. Yoriichi?"
After a moment's silence, he nodded. "Yes. I have a few questions."
Tamayo set her work aside and sat properly across from him. "Please, go ahead."
"I want to ask about Hiru," Yoriichi said, his hand absently brushing the hilt of his blade. "Now that he's the primordial demon, how does he compare to Muzan?"
"Compared to Muzan, Mr. Hiru's cells are extremely active, but far gentler," Tamayo said, her brow furrowed with faint melancholy. "Still, there's no denying he's also a Demon King. Any human who comes into contact with his blood could easily be turned into a demon."
"To what extent would someone have to be exposed to become infected?"
"Drinking or injecting his blood would be the most direct way," Tamayo explained. "But given how potent his blood is, even skin contact—or touching an open wound—could be enough."
Her eyes dimmed with concern. "What worries me most is that the blood he gave me wasn't even his most concentrated sample, yet just handling that diluted blood nearly caused me to begin assimilating."
"You were turned by Muzan, weren't you? How could Hiru assimilate you?"
"Because after I freed myself from Muzan's control, his blood no longer protects—or threatens—me," Tamayo explained patiently. "As the primordial demon, Muzan had absolute control over the demons he created. Our regeneration and Blood Demon Arts are all tied to how much of his primordial blood remains within us. The more we have, the stronger and faster we are.
After you gravely wounded Muzan over fifty years ago, I've spent decades using my own power to consume the remnants of his blood within me. Now, I have almost none left. That makes me extremely vulnerable to being infected again by any primordial blood."
She paused, then added softly, "Think of it this way—if I were a drop of water, Muzan's and Mr. Hiru's blood would both be like ink. I spent years clearing out the old ink from within me until I became clear again. But once clear, that drop of water can't resist being stained by a new drop of ink.
And as for Mr. Hiru—he's a demon who has conquered sunlight. I truly cannot imagine what he would become if he were ever to lose your restraint, Yoriichi. In this world, if he wished to destroy it, it would be all too easy."
Yoriichi lowered his gaze, silent for a long while, then rose to his feet. "...I understand. I'll go speak with Hiru."
As she watched him leave, Tamayo's violet eyes softened with sorrow. "...I only hope both of you can find peace."