Chapter 1
The sun was warm over the training grounds of the Demon Slayer Corps, birds chirping in harmony with the clash of blades and the rhythm of breathing techniques. Peace had returned—mostly.
ZENITSU (dramatically clutching his hair):
“My precious baby sister’s taking the Final Selection! What if she gets hurt? What if she sweats too much? What if her hair gets frizzy from anxiety!?”
INOSUKE (snorting):
“You mean Jia? That girl’s way cooler than you. She beat me in a noodle-eating contest last week. Respect.”
TANJIRO (smiling):
“She’s strong, Zenitsu. You should trust her more… Plus, she’s got that same Thunder Breathing as you, right?”
ZENITSU (puffing up):
“Y-Yeah but like—mine has the flair, the pizzazz, the drama! Jia’s too calm and mysterious. It’s like she… plans things.”
—
Meanwhile, at the edge of the mist-covered mountains where the Final Selection was held…
Jia Agatsuma stood quietly, arms crossed and eyes scanning the training grounds. Dressed in a custom uniform—black with lightning yellow embroidery—she adjusted her sleeves as a breeze blew her raven-black hair to one side.
JIA (muttering):
“Okay. Deep breath. Thunder Breathing, First Form: Keep-your-brother-from-screaming-in-public…”
Beside her stood Miko Kanroji, a cheerful, pink-haired girl with ribbons braided into her locks, bouncing on her feet like a jelly bean on sugar.
MIKO (grinning):
“I’m SO glad we met! You’re like, cool and quiet and mysterious! It’s like you’re the spicy sauce and I’m the pink cotton candy!”
JIA (deadpan):
“That’s… vivid. Thanks?”
MIKO (twirling):
“Oh, and I saw Tanjiro today! He helped carry my bag and I swear my heart did a Love Breathing Sixth Form right there!”
JIA:
“You named your crush as a breathing form?”
MIKO:
“Of course! It’s called Devastating Daydream Doki-Doki!”
Jia tried not to laugh—and failed.
—
After both girls aced the Final Selection (with Jia finishing so fast the trainers were still blinking when she returned), they were officially welcomed into the Corps.
That night, the grand welcome party at the Butterfly Mansion shimmered with lanterns, laughter, and tension—because every eligible Hashira and Demon Slayer was being watched by a new breed of demon Tamayo warned them about: strange, beautiful, and flirtatious.
TAMAYO (calm but serious):
“They’re… charming. Too charming. And they ask personal questions. Things like ‘Do you believe in love at first sight?’ and ‘What’s your ideal honeymoon location?’”
OBANAI (flatly):
“They sound like dating app demons.”
SANEMI (frowning):
“Can we punch them in the face?”
NEZUKO (perched on a windowsill, munching rice balls):
“Only if they ask to meet your parents on the first attack.”
Tanjiro was distracted, watching Jia from across the room. She stood by a snack table, balancing a plate of takoyaki like it was a delicate mission.
TANJIRO (whispering to Giyu):
“She moves with such precision… like each food item is a blade she’s mastered.”
GIYU (blinking slowly):
“Are you… falling in love with her plating skills?”
TANJIRO (blushing):
“N-No! I mean—maybe! No, I respect her thunder breathing. And her calmness. And her… okay maybe a little.”
Just then, Miko popped up behind Tanjiro and poked him in the ribs.
MIKO:
“So! Which of us new recruits do you think is the cutest? Me or Jia? Choose wisely, Kamado-kun!”
Tanjiro froze. His soul left his body for exactly 3.2 seconds.
TANJIRO (panicking):
“Uhhh I think everyone’s inner spirit is beautiful!”
JIA (approaching with a raised brow):
“Did I just hear a diplomatic dodge, Kamado?”
MIKO (gasping):
“Oh my god she’s doing the intimidating older sister vibe and she’s not even older!”
Jia simply popped a takoyaki into her mouth and smirked slightly.
JIA:
“Well. I’d flirt with me too, if I were a demon.”
The room burst out laughing. Tanjiro noticed Miko was too close and his heart did a weird flip.
TANJIRO (visibly stiffening as Miko leaned in):
“Uhh—Miko-san… y-you’re kinda close...”
MIKO (blinking innocently):
“Huh? Oh, sorry! I just wanted to see what flavor takoyaki you were eating!”
She smiled sweetly, unaware—or maybe very aware—of how her closeness sent Tanjiro’s brain into static.
TANJIRO (internally):
“Why is my heart doing cartwheels?! Focus. Sun Breathing. Not Sun Blushing.”
Just as the air grew warm and awkward between Tanjiro and Miko, a wave of awe-inducing presence entered the room like a burst of fire in slow motion.
???:
“I see the future of the Corps burns bright today!”
All heads turned.
There, by the wide doors of the Butterfly Mansion stood the unmistakable figure of Rengoku Kyojuro.
He was taller now, broader, his flame-patterned haori flowing like a blazing banner. His once-long hair had been trimmed to just below his shoulders, still tied back in that familiar ponytail, but neater, more refined. His eyes—those ever-burning golden-red eyes—still shimmered with unwavering conviction and warmth.
JIA (freezing mid-bite):
“...I forgot how to breathe.”
It had been two years. Two long years since she’d only seen him from afar, right after the final battle. She had come to check on her brother at the recovery ward. That day, she had glimpsed Rengoku from the hallway, laughing with Tanjiro and Inosuke. She’d instantly backed away before anyone noticed her, her heart hammering like thunder.
But now, he was here. In the same room. Close enough that she could hear the timber of his voice.
MIKO (slyly whispering):
“Dear Jia~ someone’s got a little volcano in her chest~”
JIA (without looking away from Rengoku):
“Not. A. Word. Or I will tell everyone about your ‘Love Breathing Daydream Doki-Doki’ diary.”
MIKO (gasping and instantly backing off):
“Okay fair. Respect. I’m silenced.”
Across the room, Zenitsu had been monitoring his sister like a hawk all evening, balancing protective big brother energy with professional paranoia.
ZENITSU (squinting dramatically):
“Do. NOT. Tell me…”
He stepped closer, his tone becoming theatrical as he leaned around to get a better look at her face.
“You did. You did. Is that… a blush?”
JIA (startled, snapping out of it):
“I—No?! That’s just… spicy takoyaki.”
ZENITSU (horrified whisper):
“He’s Rengoku Kyojuro. The flame pillar. He makes people cry from inspiration, not… flirt blushing! Jiaaaa!!”
INOSUKE (from the snack table, mouth full):
“What’s the big deal? I think I have a crush on Rengoku too, and I don’t even know what feelings are.”
GIYU (nodding solemnly):
“He does have impressive hair. Even short.”
Meanwhile, Rengoku had already made his way toward the newest recruits. His powerful steps were filled with purpose, but his expression was nothing but warm pride.
RENGOKU (grinning):
“Welcome to the Demon Slayer Corps! You’ve passed the Final Selection with honor. May your blades burn bright!”
MIKO (whispering):
“He’s even more majestic up close…”
Jia stood rooted as he approached. He paused before her and met her eyes directly.
RENGOKU (kindly):
“You must be Agatsuma Jia. Thunder Breathing… and sister to that passionate spark plug Zenitsu, if I recall correctly.”
JIA (barely audible):
“...Yes. That’s me.”
RENGOKU (smiling, hand to chest in a small respectful bow):
“Your reputation precedes you. I look forward to seeing your strength on the field. Fight with courage—and never let your flame fade.”
JIA (internally screaming):
“He. Bowed. WHAT DO I DO WITH MY FACE RIGHT NOW.”
She bowed back quickly, almost forgetting how limbs worked.
JIA (quietly):
“I… I’ll do my best. Thank you, Rengoku-san.”
As he walked on, Jia let out a breath she hadn’t realized she’d been holding. Her fingers curled against her palms.
MIKO (smirking beside her):
“He remembered your name. Girl, if that’s not fate flirting with you, I don’t know what is.”
ZENITSU (frustrated groan):
“This is my villain origin story. I swear I can hear the romantic background music swelling.”
MORNING, BUTTERFLY MANSION — TRAINING ASSIGNMENT DAY
The courtyard buzzed with anticipation as a list of pairings and assignments was tacked to the message board with a neat stamp from the Corps. Recruits huddled around like kids peeking at exam results.
MIKO (reading aloud dramatically):
“Assigned partners for advanced one-on-one training: Miko Kanroji... Tanjiro Kamado.”
Her voice cracked slightly.
MIKO (suddenly stiff):
“T-Tanjiro?! Me?! With Tanjiro?! As in—THE Tanjiro Kamado, the handsome one who smiles like sunshine and fights like poetry!?”
She whirled toward Jia, already sweating.
MIKO:
“I’m not ready. I didn’t even bring my best training ribbon!”
JIA (brows twitching, scanning for her name):
“Calm down, it’s just a—wait.”
Her eyes landed on the next line:
“Jia Agatsuma… Flame Hashira: Rengoku Kyojuro.”
Time stopped.
Birds paused mid-flight. The wind held its breath. Somewhere, Zenitsu probably sensed a disturbance in the Force.
JIA (quietly):
“...You’re kidding.”
MIKO (leaning dramatically over her shoulder):
“Whaaat?! Rengoku?! Jia. JIA. This is divine matchmaking! The Universe is screaming ‘you’re welcome’ right now!”
JIA (panicked):
“I’m going to spontaneously combust before the warm-up drills.”
—
LATER THAT DAY – MOUNT HOKKAIDO TRAINING GROUNDS
Jia walked slowly up the forest trail, her uniform crisp, her hair tied back tight, her heart having its own version of Thunder Breathing Seventh Form: Cardiac Havoc.
Ahead, standing at the cliff’s edge against the blue sky and distant snowcaps, was Rengoku Kyojuro—arms crossed, eyes sharp, smile warm.
RENGOKU (booming voice):
“Agatsuma Jia! You’re punctual. A good sign of discipline!”
JIA (bowing stiffly):
“Y-Yes, Rengoku-san. I’m honored to train under you.”
RENGOKU (nodding proudly):
“Let’s begin with core endurance. Thunder Breathing requires explosive power, but without inner strength, lightning cannot strike twice. We will train your breath, your spirit, and your flame.”
JIA (thinking):
“I’m pretty sure the flame part’s already happening… in my face.”
—
SOMEWHERE ELSE — A SUNNY FIELD NEAR THE RIVER
Tanjiro was stretching beside a nervous-looking Miko who was trying not to look directly at him for more than two seconds at a time. She failed.
TANJIRO (smiling kindly):
“Are you feeling okay, Miko-san? You seem… twitchy.”
MIKO (laughing way too loud):
“Hahaha who me?! Twitchy? Pfff! This is just how I flirt—I MEAN breathe!”
She immediately started doing awkward jumping jacks.
TANJIRO (internally):
“I have no idea what’s going on but I respect the enthusiasm.”
TANJIRO (aloud):
“Let’s start with Love Breathing posture. Mitsuri-san told me you have a strong first form. I want to see it.”
MIKO (murmuring):
“Oh I’ll show you love, alright.”
—
BACK ON THE MOUNTAIN, JIA’S TRAINING GROUND
Rengoku had them running uphill with weighted logs on their backs.
RENGOKU (calling out):
“Let the mountain test your resolve! Lightning without strength is just noise!”
JIA (gasping, under her breath):
“This man trains like he’s trying to marry you to discipline itself…”
Finally, during their rest break, Rengoku knelt by the fire he built with bare hands. He handed Jia a roasted rice ball with calm confidence.
RENGOKU (smiling):
“Food restores the flame. You’re doing well, Agatsuma. You remind me of your brother—but quieter. More centered.”
JIA (blushing furiously):
“I, uh… I cook. That helps me focus. Unlike him… who screams at potatoes.”
RENGOKU (laughing loudly):
“HAHA! A fine skill! You should prepare something next time. I’ll bring the firewood.”
Jia nearly choked on the rice ball.
JIA (thinking):
“Is that… was that… an invitation?!”
From behind the trees, Zenitsu peered out in horror, scribbling in his “Things to Cry About” notebook.
