Crossover: The Problematic Deity of Arcadia

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Stepping in from the back garden into the Butterfly Mansion, Ryo caught sight of the current head of the Demon Slayer Corps, Kagaya Ubuyashiki, across the corridor.

The man wore a plain kimono, his skin pale and sickly. Faint purple markings spread across his forehead—signs of some long-running pain.

He looked like someone whose days were numbered.

Following behind Ryo Yagami, Shinobu and Makomo immediately recognized the man and bowed respectfully.

"Lord Ubuyashiki."

"Shinobu. Makomo," Kagaya greeted them softly. He remembered them—not surprising, given how he'd memorized the backgrounds and quirks of every member of the Corps.

Not because he needed to, but because he wanted to. If these people were willing to risk their lives fighting demons, he refused to let them be forgotten.

He smiled gently and spoke with sincere politeness. "Would the two of you mind giving me a moment alone with Mr. Yagami? I'll be staying here for a couple of days. If you have any questions, feel free to come see me afterward."

"Understood." x2

The two women nodded, then quietly headed to another part of the Mansion.

Before leaving, Shinobu gave Ryo a look, as if she wanted to say something, but ultimately stayed silent.

Ryo glanced at the pair as they left, then turned his eyes back to Kagaya with some curiosity. "Interesting. For someone with your condition to have lived this long… you're really something."

"You could see the curse just by looking?" Kagaya gave a wry smile, covering his mouth as a cough slipped out. 

Ryo raised a brow. "Not curious how to break it?"

He'd never made a big deal about his origins, but someone like Kagaya probably suspected his background had ties to gods or myths.

Even so, Kagaya shook his head. "Once Muzan Kibutsuji is dead, the curse will lift."

Hearing that, Ryo chuckled softly. "You make it sound like Muzan's immortality is being bought with your suffering."

"It basically is," Kagaya admitted with a faint, bitter smile. "According to scraps left in our family records, this illness didn't exist in our bloodline a thousand years ago. But ever since the Demon King Muzan emerged… it's been with us."

Ryo rubbed the bridge of his nose, looking amused. "You people are weird."

"Oh? How so?" Kagaya looked genuinely intrigued by the comment.

This man, supposedly tied to the divine, was confused by his illness?

Ryo explained casually, "This world was supposed to be normal… and yet you've got Breathing Styles, demons, supernatural powers, and curses—but no cohesive system to tie it all together."

He gave a short laugh. "It's like some god was playing a prank."

Ryo gave up trying to figure it out. All of this scattered, inconsistent power had no real future—nowhere to go. It paled in comparison to the clear, structured strength of the Little Garden.

At least there, you could see where things were headed—and actually reach for them.

"If that's the case," Kagaya said calmly, "then maybe this god never shed a single tear for us."

It was a bleak statement, but not a hopeless one. Whether a god existed or not didn't change his goal—or the Corps' mission.

Kill Muzan Kibutsuji. End the cycle of demons devouring humans and humans retaliating with bloodshed.

Ryo shrugged and grinned. "Fair enough. Not gonna invite me to sit down?"

"Please." Kagaya gestured politely toward the tea room.

As they entered, they found Kanae Kocho already kneeling by the tea table.

She smiled at their arrival, then quietly sat beside Ryo, pouring tea for them with practiced grace—trying her best to blend into the background.

Ryo glanced at her. When she wasn't speaking, Kanae had this serene, classical beauty to her.

That is… when she wasn't being a total airhead. Especially around Kanao.

Shinobu had said it before—Kanae doted on Kanao way too much.

"Is there something on my face?" Kanae asked, blinking in confusion under Ryo's stare.

He answered plainly, "No."

Her brow twitched. Instinct told her he'd just thought something very rude.

But this wasn't her scene. She offered the tea with a courteous smile. "It's just simple tea—please don't mind."

Then she went completely silent.

Now alone with Kagaya, Ryo set down his cup and said, "Shall we get straight to the point?"

Kagaya nodded, coughing lightly. Then, to Ryo's surprise, he took a deep breath—and bowed his head to the floor.

"I know it's a bold request. But Ryo Yagami… I want you to become the next leader of the Demon Slayer Corps."

There was a stunned silence. Even Kanae couldn't hold back a startled, "What?!"

"Lord Kagaya, what are you saying?" she blurted, looking completely dumbfounded.

But Kagaya didn't move. Kneeling, head down, he exuded a quiet but overwhelming determination.

Ryo, unfazed, sipped his tea and said calmly, "And what debt do I owe the Demon Slayer Corps?"

Did they ever save his life? Nurse him back from the brink like Canaria or Black Rabbit had?

His attitude was clear—he didn't feel any personal connection to the Corps.

Sure, he could joke around with Kanae, or tease Shinobu without caring about her "poisoning" threats.

But that was different. Kanae was a friend from the forum. Just chatting with her earned him points.

Shinobu and Kanao? They were part of Kanae's family—an indirect connection at best.

The Demon Slayer Corps itself? Nothing.

And Ryo wanted Kagaya to understand that loud and clear.

"I understand," Kagaya replied solemnly. "Then… the entire Ubuyashiki family's assets are yours to command."

"Lord Kagaya!" Kanae's face turned pale.

He was offering the entire Ubuyashiki estate?

Was he really going to hand over a thousand years of heritage like this?

But Ryo caught the nuance.

"The Ubuyashiki family's assets, huh?"

Not the Corps. Just his personal family.

If it were anyone else, Ryo might suspect wordplay—but not Kagaya.

The man probably felt he had no right to speak for the rest of the Corps. So he was offering only what he could—everything he had.

Ryo raised an eyebrow. "All that family legacy… just to kill Muzan Kibutsuji? Is it really worth it?"

"It's," Kagaya answered with a genuine smile.

"The health of my loved ones means more to me than wealth or legacy."

And by "loved ones," he meant not just his children—but every Demon Slayer under his command.

His two deepest wishes were simple: for his family to be healthy… and for Muzan to die.

And in truth, they were one and the same.

Which meant Muzan's death was non-negotiable.

Ryo chuckled, then leaned back. "Fine. Within a month… Muzan Kibutsuji will be dead."

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