Crossover: The Problematic Deity of Arcadia

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Mount Natagumo.

A mountain so deep and remote that the locals had long since stopped going near it.

Why? Simple.

Because demons live there.

Even in this age of limited information, people still know where not to go. And after an entire family of woodcutters living there disappeared without a trace, the mountain was officially labeled a forbidden zone by the villagers.

But just as dusk began to settle in, Mount Natagumo welcomed two new visitors—something that hadn't happened in a very long time.

One was a man with silvery-white hair, golden eyes, and a pair of horns sprouting from his head. His very presence exuded power and authority. The other was a woman in a flowing haori layered over a Demon Slayer Corps uniform.

They were Ryo Yagami and Kanae Kocho.

And despite the fact that they'd been standing at the forest's edge for more than ten minutes already, Kanae's curiosity still hadn't run its course.

She turned to Ryo with a twinkle in her eye. "Ryo, can I touch your horns?"

"No."

Ryo shot her a glare and added, "Also… did you forget something?"

"Huh? Did I?" Kanae blinked in confusion, tilting her head like a puzzled kitten.

Ryo let out a cold laugh. "If you want to touch my horns, fine. But then I get to touch Kanao's hair. Deal?"

"No way!" Kanae shook her head furiously. "Kanao is off-limits!"

Before Ryo could say anything else, Kanae quickly followed up, "What if I trade you Shinobu for her? How about that?"

Ryo came to a stop. He turned to look at Kanae, who was giving him a hopeful look, like she was afraid he'd say no.

"…You really are Shinobu's sister?"

"Eh?"

Kanae blinked again, tilting her head. "I am though?"

Ryo didn't explain. He simply turned around and started walking up the mountain.

Kanae hurried after him. She looked like she wanted to say more, but then her expression suddenly changed. A cheerful smile crept onto her face as she spoke in a singsong voice.

"Looks like someone's coming~ Isn't that right… Lord Muzan?"

Ryo gave her a sidelong glance, then turned his eyes skyward.

The sun had just dipped below the horizon, casting an orange glow along the edge of the trees. But the towering forest blocked most of the light, leaving everything around them in deep shadow.

That's when footsteps echoed through the woods.

A woman stepped out from between the trees—long white hair, pale skin, and a pure white kimono. Her features were delicate, almost ethereal.

"Demon Slayer Corps... and a demon? What kind of team-up is this?"

She'd originally planned to ambush Kanae from the shadows. But Ryo's presence had completely thrown her off.

He wasn't doing anything threatening—he was just standing there. Yet the pressure rolling off him made her knees weak. And Kanae… she was standing obediently behind him. Then there was what she had said—Lord Muzan?

Wait. Was she referring to that Muzan? Kibutsuji Muzan, the King of Demons? The one every demon originated from?

She herself had been created by Muzan's blood—delivered through one of his subordinates. But she'd never seen the Demon King in person.

Still, the man in front of her… could he really be him?

And then, Ryo looked at her.

"Huh?"

The white-haired demon blinked.

Wait—why was she suddenly kneeling?

What the hell?! Why am I kneeling??

She tried to stand back up, confused and alarmed.

Then Ryo's cold voice cut through the air.

"Who said you could stand?"

She froze.

Sweat the size of raindrops poured from her forehead, soaking into the earth beneath her. It felt like a mountain had landed on her back, crushing her with unimaginable pressure.

Her mouth fell open. "Ahh—!"

The air's too heavy—I can't breathe—I'm going to die—In just three seconds, she felt like death was breathing down her neck.

Then Ryo spoke again, his voice completely indifferent.

"Where's Rui? Tell him to come meet me."

Rui. Lower Rank Five.

The current "master" of Mount Natagumo.

As one of Muzan's twelve hand-picked demons—divided between Upper and Lower Ranks—Rui held the title of Lower Five.

And the fact that this man casually mentioned Rui by name… The white-haired demon's eyes widened in realization.

This man… really is Lord Muzan!

"I understand! Right away, Lord Muzan! I'll go get Rui!"

Without another word, she dropped to all fours and scrambled up the mountain, determined to fulfill "Muzan's" command as fast as demonically possible.

Kanae blinked and muttered, "That worked… way too easily."

Do these demons seriously not even recognize their own demon king?

Ryo, ever calm, replied, "What do you expect? These countryside demons don't know anything."

To be fair, it was an easy mistake to make. Rural demons had never experienced Reiatsu before—and it wasn't far-fetched that they might confuse it with Muzan's racial dominance.

After all, Reiatsu was a form of soul-based suppression, not unlike aura or killing intent.

With Ryo's power, if he unleashed it fully, even a captain-level Soul Reaper could be crushed to death. Compared to that, these demons were nothing.

Honestly, getting mistaken for Muzan was no surprise. Even if he wasn't, the moment Ryo pulled out a Zanpakutō and claimed to be Muzan, no demon would dare question him.

That's how confident he was in this impersonation.

Sure enough, less than ten minutes later, the white-haired demon returned—dragging Rui along behind her.

As soon as he saw Ryo, Rui's expression turned icy. He looked straight at the female demon.

"Mother… what's the meaning of this?"

His so-called "mother" was already kneeling on the ground, panic all over her face.

"What do you mean? Hurry, Rui! Kneel before Lord Muzan!"

Rui's tone was cold. "What nonsense are you spouting? That's not Lord Muzan."

As one of Muzan's direct subordinates, Rui had, of course, met the man in person.

And Muzan looked nothing like this silver-haired guy. Muzan had this flashy, Michael Jackson style thing going on. There was no way he'd mistake that.

What—do you think I'm blind?

"Not Lord Muzan…?"

The woman froze.

Her expression twisted with embarrassment—then panic—then desperation.

Wait… didn't Rui once say Muzan could change his appearance?

She gasped and blurted out, "But Rui, didn't you say Lord Muzan could change forms whenever he wanted?!"

Rui blinked.

That… was true.

According to veteran demons, Muzan often changed identities—sometimes a young man, sometimes a child, sometimes a woman, or even an old man.

They said he did it for fun.

Then again… others said he usually changed form after being scared by something.

So... was this man in front of him actually Muzan?

Rui stared hard at Ryo, suspicion in his eyes.

"You've changed a lot, Rui."

Ryo smiled and stepped closer.

Rui instinctively backed up—but seeing no visible weapon, he didn't seem too afraid.

Ryo walked right up to him, still smiling, and reached out to gently pat his head.

And then—

Crack!

Ryo twisted Rui's head clean off with a casual, practiced motion.

"You've changed, alright. You didn't even kneel the moment you saw me. That's disappointing."

As Rui's decapitated head hit the ground, his eyes widened in recognition.

That overwhelming pressure… that merciless violence…

That had to be Lord Muzan!

No doubt about it.

This guy…This guy is definitely Muzan-sama!

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