Demon Slayer : Heir to the Moon

I woke up to the taste of bitter medicine and disappointment.

Again.

"Why do these potions always taste like boiled regrets?" I muttered, forcing down another cup of Shinobu's daily torture.

"They make this worse on purpose," I added, glancing into the cup like it had personally offended me.

A tiny helper girl gave me a cheerful smile as she handed over breakfast—rice, grilled fish, some miso soup. All perfectly arranged.

"T-Thank you," I mumbled.

"You're welcome, big brother!" she chirped, already skipping off down the hallway like some miniature battlefield medic.

My arms ached a little less today.

Which meant only one thing: writing.

I sat by the window and began scratching out a letter to Master Junjiro with what could generously be described as handwriting. A deranged squirrel could've done better. But it was readable. Barely.

"Master. I am alive. Not well, but alive. Fought a strange demon. Foolish kind. Got stabbed. A lot. Saved some people. Met a Hashira. Got yelled at by a scary woman who is also a Hashira. Now recovering. Will visit soon. If you can read this, my handwriting has improved. Slightly."

When I handed the letter to the same helper girl, I asked, "Where can I post this?"

"I'll take care of it!"

"…Are you sure?"

"Of course!"

I hesitated. "…Even if it's addressed to 'a mountain somewhere near Goka Village, just look for an old man with a scowl'?"

She blinked, then smiled. "Got it."

"How?"

"We use Kasugai crows to deliver letters."

"Damn.. Makes Sense."

I gave her a silent salute. Truly, these children were terrifyingly competent.

Out in the courtyard, I tried to practice Total Concentration: Constant again.

Inhale… hold… exhale…

My lungs wobbled. My focus cracked. My ribs whispered threats.

Still—better than yesterday.

"Doing great!" Tanjiro's voice chimed behind me. "Need a hand?"

"Only if it's not going to explode my spleen," I said, wobbling slightly.

Tanjiro laughed and sat beside me. He walked me through the technique again—slow, patient. The rhythm of it. The balance. The flow of breath, constant and steady, like the river outside the mansion.

"You're picking it up really fast," he said after a while.

I grunted. "I've been breathing for years."

He smiled. "But now you're really breathing."

A few days passed like that. My body healed. My breath grew stronger.

One day, Inosuke burst into my room without knocking, declaring:

"I'M THE KING OF MOUNTAINS!! WHO ARE YOU!?"

I blinked from bed. "…Ryo."

"NICE TO MEET YOU, SAYO!"

"It's Ryo."

"I SMELL STRENGTH! LET'S WRESTLE!"

He pounced.

I thought how many more times he is gonna say the same thing everyday. Does he have short time memory loss? Its like every time he meets me, he is seeing me for the first time.

That's how I ended up arm-wrestling a half-naked boar-headed wildling while still bandaged.

He lost.

Then demanded a rematch.

He lost again.

"YOU'RE STRONG! I LIKE YOU, RAMO!" he roared, collapsing onto the floor.

"It's. Ryo."

One evening, Tanjiro sat by the porch, gently cleaning a wooden box.

"Preparing a gift?" I asked.

Tanjiro smiled. "Not quite. This is for my sister."

"Your…?"

He looked around, lowered his voice slightly. "She's a demon."

I blinked. "Oh."

"She travels with me."

"…Inside the box?"

He nodded. "She's harmless. Doesn't eat humans."

I stared at the box, then at him. "You do realize that's the most suspicious way you could've said that?"

Tanjiro laughed. "Would you like to meet her?"

I hesitated, then nodded. "Sure."

He gently knocked on the side of the box. "Nezuko, it's okay. You can come out."

The box opened. A small girl stepped out—eyes wide, bamboo muzzle in place. She looked at me, tilted her head… then walked straight to a bowl of water and started poking a goldfish with both hands like it was the most fascinating thing in the world.

I didn't sense any bloodlust. Not even a flicker of demonic pressure.

"…She feels less like a demon than that masked man I met."

Tanjiro blinked. "Masked man?"

"Don't worry about it."

Nezuko looked up at me, then gently offered the goldfish.

I blinked again. "She's pure," I said. "It makes sense now. Why I never sensed her."

Tanjiro's eyes softened. "Thank you."

"I hope you can protect her."

"I will."

Later that night, I returned to my room—my own room, far away from the Inosuke Screaming Experience™.

I lay on the bed, looking at the ceiling, breathing steadily.

Still working on Total Concentration. But I was close.

I owed that much to everyone I met here.

A knock came at my door.

"Ryo?" Zenitsu peeked in, eyes wide.

I groaned. "What now?"

He stepped inside cautiously, clutching the doorframe like it owed him money. "W-What were you doing with Nezuko?"

I raised an eyebrow. "Talking."

His lip quivered. "T-Talking?"

"Yes. Like normal people do."

"Listen…" He puffed out his chest, trying his best to look threatening. "If you go near her again, it won't end well for you!"

He was trembling so hard I thought the floor might start shaking.

I stared at him. "Relax. I'm already engaged."

He froze.

"…E-Engaged?"

"Yeah."

"You're seventeen!"

"…And?"

He dropped to his knees in slow motion. "This is so unfair…"

"You scream too much," I offered helpfully.

"I scream because I feel things deeply!"

I rolled over and pulled the blanket over my head. "Goodnight, Zenitsu."

"…How did you get engaged? Was it an arranged thing? Did you save her life? Was it a destiny-bond thing?"

"Go to bed, Zenitsu."

He sighed and crawled out the door like a disappointed ghost.

Finally—peace.

To Be Continued…