Just when Yosuke found himself at a loss, Hakuji and Gyutaro returned to the Butterfly Mansion from outside.
The two went straight to Yosuke's room to report in.
"Yosuke-sama, we've returned!"
Gyutaro grumbled, "What a shame! Hakuji and Ume both ran into Upper Ranks Three, One, and Six—but I didn't even get to meet a single one of them."
Yosuke smiled and shook his head. "As long as you all made it back safely, that's what matters. The Twelve Kizuki have taken a serious blow, so there'll be a lull for a while. But battles won't stop coming anytime soon. Rest here at the Butterfly Mansion for now. I also need some time to sort through a few things myself."
Hakuji looked curious. "Sort through… what things?"
Yosuke's smile faded, his face turning solemn. "I'm investigating whether Kibutsuji Muzan and I were deliberately turned into demons… by someone—or perhaps by some organization."
"What? Deliberately? That's impossible, Yosuke-sama! You're overthinking this, aren't you?"
Both Hakuji and Gyutaro were stunned—almost finding the idea absurd.
But Yosuke's expression remained grim. "I'd like to believe I'm just overthinking it too… but when I piece together the few clues I've found so far, it all points to one thing: from the very day I became a demon, things were never as simple as they seemed."
A chill ran down Hakuji and Gyutaro's spines.
If both Yosuke and Muzan had been deliberately turned into demons, then the one behind it all must be utterly terrifying.
After exchanging a few more words with the two, the Butterfly Sisters, Tamayo, Koyuki, and Ume all came to Yousuke's room as well.
They, too, had noticed something off about Yosuke—he had been unusually withdrawn these past few days.
When Yosuke explained his suspicions to them, everyone was left speechless with shock.
A heavy gloom clouded all their faces.
Yosuke forced a gentle smile again. "All right. For now, it's just my own speculation. Maybe I really am just imagining things. Go about your business as usual—don't worry about me."
"Yes, sir."
After that, Yosuke spent all his days shut inside the Ubuyashiki estate, searching for clues within the records and archives the Ubuyashiki clan had preserved.
What Inatama Kain (the thieving crow demon) had stolen from the Demon Slayer Corps headquarters were only copies—the original manuscripts were still stored safely in the Ubuyashiki household.
Since Kagaya Ubuyashiki had already lost his sight and could no longer assist directly, he asked his wife Amane to help Yousuke instead—after all, the more hands, the better.
Inside the spacious study, the only sounds were the soft rustling of pages being turned by Yosuke and Amane. Kagaya sat quietly to the side, sifting through his memories for anything he could recall about the lineage of the Divine Priests.
After several days of searching, Yosuke finally found a record relating to himself and Kibutsuji Muzan's transformations into demons.
"When the bloodline neared extinction, the Ubuyashiki clan received guidance from the Divine Lord."
"A demon appeared among their kin. Only by pouring one's heart and soul into defeating that demon would the clan's bloodline endure."
This passage immediately caught Yosuke's attention.
Why would the so-called Divine Lord know that defeating a demon would preserve the clan's bloodline?
From Yosuke's fragmented memories, he recalled that after Muzan's death, the curse upon the Ubuyashiki descendants had indeed been lifted, and they went on to live long lives.
Could that truly have been the work of a god?
Had the Ubuyashiki clan truly received divine revelation?
Yosuke's mind then drifted to a certain man—Tsugikuni Yoriichi, the natural-born nemesis of the Demon King.
According to the natural order, when balance is broken, nature resets itself—returning things to equilibrium.
In the age when demons ran rampant, Yoriichi appeared out of nowhere—blessed with transparent perception, bearing the mark, and gifting humanity the Breathing Techniques to fight against demonkind.
Could Yoriichi himself have been a vessel of divine revelation—perhaps even the divine revelation itself, sent by the gods to humanity?
The Divine Priests had long maintained close ties with the Ubuyashiki clan, existing even before Yosuke and Muzan's transformations. Yet, throughout all this time, almost no one had paid attention to that mysterious family.
Had he not stumbled upon these hints now, their existence might still be veiled in obscurity.
A thousand years had passed without leaving a single trace—shrouding the Divine Priests in an unfathomable layer of mystery.
The more Yosuke read, the deeper his unease grew.
He noticed a chilling pattern—throughout the centuries, at every critical turning point, some special person or event would arise to restore the balance between humans and demons.
For instance, after the great battle centuries ago when Yosuke and the Demon Slayer Corps fought against Muzan:
Though the Demon Slayers suffered devastating losses and Muzan's army surrounded them, the Corps somehow survived.
Could Muzan truly have been incapable of eradicating them? Of course not.
Something had happened during that period—something history had never recorded.
The Demon Slayer Corps and the demons had clashed for a thousand years, yet neither side ever truly vanished. That couldn't be coincidence.
Someone—somewhere—had been pulling the strings all along, treating everyone as pieces on a vast chessboard.
And Yosuke himself was one of those pieces.
At Yosuke's request, Amane continued searching through the archives and eventually found a record detailing the aftermath of that ancient battle between Muzan, Yousuke, and the Demon Slayer Corps.
Yosuke carefully turned the brittle pages.
After the final confrontation with Muzan, the Corps had been devastated—barely one in ten members survived.
The then-head of the Ubuyashiki clan, Ubuyashiki Kayaga (1st), had perished in battle, and his successor, Ubuyashiki Kiriya(1st) assumed leadership.
With Muzan's surviving demons hunting them down, the Corps was driven to the brink of extinction.
At that desperate moment, a woman from the Divine Priest family arrived, marrying Ubuyashiki Kiriya and bringing with her the Divine Lord's revelation: Mount Akaiiwa (Red Rock Mountain) would be the Demon Slayer Corps' sanctuary, a place where Muzan's demons could not pursue them.
Heeding the divine message, Kiriya led the Corps to Akaiiwa, where they recuperated and eventually flourished once more.
Strangely, after the move, Muzan's demons abruptly ceased their pursuit—and vanished from sight entirely.
After reading the record, Yousuke furrowed his brow.
"Another… divine revelation."
He silently pondered.
Just what role did this mysterious Divine Lord and the Divine Priest family play in all of this?
Were they benevolent saviors… or hidden conspirators with an unseen agenda?
Night had grown deep. Kagaya, whose frail body could no longer endure the long hours, had dozed off against the wall.
For several days he had accompanied Yosuke and Amane in their search through the archives, pushing himself beyond exhaustion. Seeing this, Yousuke decided it was time to stop for the night.
Before leaving, Yosuke asked Amane for a vial of her blood—hoping that by studying it, he might uncover some clue tied to her lineage as a descendant of the Divine Priests.
After receiving the blood sample, Yosuke spoke softly.
"That'
s enough for tonight. Take care of Kagaya. I'll be going now."
Amane nodded gently. "Please have a safe journey, Yosuke-san."