Peach Mountain.
The March wind carried a gentle touch, like a mother's hand brushing through the peach blossoms covering the mountainside. Petals rose and fell, dancing like butterflies.
A pink petal landed on the nose of a boy sleeping beneath a peach tree. His arms were folded behind his head, his breathing steady, drool trickling from the corner of his mouth as he muttered in his sleep.
"Shinobu-tan, my love… your breast it so soft… hehehe!"
Another fine day, another one of Tendo Kazama's wild daydreams.
He had short crimson hair and a fair, harmless-looking face.
"You little brat! Slacking off again?! You trying to kill me?!"
A thunderous roar echoed, followed by a wooden sword flying from the dense peach branches in the distance.
The force of its swing sent a flurry of petals scattering.
Just before the wooden sword could crack his skull open, Tendo Kazama tilted his head slightly—the blade embedded itself into the tree.
His golden eyes lazily cracked open as he stretched and drawled.
"Old man, it's the same moves over and over again. What's the point of practicing it?"
"I could do them in my sleep!"
"Also—are you even my real master?!"
"You were aiming to kill me!"
He pointed helplessly at the wooden sword beside his head—it was buried deep enough to split a skull.
"If I'm not your master, why'd I pick you up in the first place? Just to feed you for free?"
"Brat, I know you've got talent, but if you don't put in the work, you'll waste it all!"
"Now go train!"
Tendo Kazama's vision was now filled with a short old man—about the same height as his twelve-year-old self.
The old man had thick eyebrows, large eyes, and long white mustache, giving off an intimidating aura.
His right leg was a prosthetic, forcing him to walk with a cane.
His name was Kuwajima Jigoro—the former Rumble Hashira of the Demon Slayer Corps.
After losing his leg, he retired to Peach mountain and became a Breeder.
Twelve years ago, he found an infant at the foot of the mountain—that infant was Tendo Kazama.
What the old man didn't know was that within that tiny body resided a soul not of this world.
"Old man, let's take a break from training!" Tendo Kazama put on a pitiful smile and pleaded.
Perhaps due to being a transmigrator, he possessed extraordinary talent in swordsmanship, coupled with keen perception.
It wouldn't be an exaggeration to say he was born for the sword.
"No. If you don't swing your sword a thousand times today, no dinner for you!"
"Swinging the sword is fundamental. Without a solid foundation, your blade won't be steady..."
Sensing the old man was about to start lecturing again, Tendo decisively chose to make a run for it.
"Old man, I already finished my swings this morning. It's break time now—see ya later!"
Hearing this, Kuwajima Jigoro's lips twitched as he recalled the straw dummy on the hill, dressed in clothes and holding a wooden sword.
If he hadn't gone to check it himself, he might have believed it.
This disciple of his was good in every way—except for being too carefree and lazy.
"You little brat, using a moving dummy to trick me!"
"I don't know how you managed to make a moving puppet, but wasting your talent like this—I'm gonna beat you for sure!"
Tendo's face darkened. Oh no, he found out! He immediately bolted.
The moment he took off, a brilliant golden streak of lightning carved a vivid trail through the peach orchard.
"Old man, that's not fair! Using sword techniques—that's cheating!"
Tendo's face fell as he protested.
"Even with my bad leg, catching you is child's play!"
Kuwajima Jigoro pressed a hand on his disciple's shoulder with a terrifyingly kind smile, gripping a wooden sword in the other.
His tone was stern, yet carried the air of a veteran who still had fight left in him.
Tendo activated his ultimate technique—the Leg-Clutching Plea—in an attempt to awaken his master's paternal instincts.
"Master, we've relied on each other since I was little! If you beat me to death, who's gonna take care of you in your old age?!"
"Master, my kind, strong, loving, and handsome master!"
Tendo poured on the tears, appealing to both emotion and reason.
Kuwajima Jigoro felt something was off.
Since when did we start talking about my funeral arrangements?
"You brat, can't you wish me well for once?"
"Today, I'll teach you what it means to be a strict master raising a top disciple—Breath of Thunder, First Form: Thunderclap and Flash!"
"Ahhh! Owwww!"
Soon, screams echoed through the peach orchard.
"Master, master…"
"It hurts, it hurts!"
"Old man, if you keep this up, we're gonna have to talk about your tea dates with Granny Yamamoto down in the village!"
Since he was already getting beaten, Tendo decided to dig up some dirt on the old man.
"That was her thanking me for helping her! What's with that tone? Like I did something shady…"
Kuwajima Jigoro immediately retorted, swinging his sword even faster—though he wasn't serious.
Otherwise, a mere brat wouldn't last a second under a Hashira's pursuit.
"Hey, I wouldn't mind having a new master's wife. The granny's nice—she always gives me treats!"
Tendo added fuel to the fire.
"Breath of Thunder, Second Form—"
No sooner had he spoken than the old man's swordplay grew fiercer.
Barely dodging, Tendo knew another beating was imminent.
"Ahhh!"
"Murder! Arson! Robbery!"
No matter how loud Tendo screamed, no one would hear him.
After all, the vast peach mountain was home to only these two.
The old man's sword strikes were getting faster, yet each one had purpose—he was training Tendo's reflexes.
He had to admit, this kid's perception was inhuman.
Having been a Breeder for decades, Tendo's talent was terrifying, almost like he was the son of a god.
"Old man, that's too much! I'm gonna—"
"Gonna what, you ungrateful brat!"
Old Man Kuwajima's temper flared instantly.
He wouldn't tolerate even a hint of insinuation about him and Yukiko—their relationship was pure.
"I'll just dodge then! You won't land many hits anyway!" Tendo stuck out his tongue teasingly, his tone laced with mockery.
"Oh ho! Mocking me now? Got some nerve, haven't you!"
As the sun dipped below the horizon, delicate peach blossoms were painted crimson.
On the mountainside, the young one ran while the old one chased with a wooden sword.
Such was another day of "master's kindness and disciple's filial piety" on Peach Mountain.
Finally, Tendo Kazama grew tired—mostly hungry.
Plopping onto the ground, he spoke in a soft, childlike voice, grinning:
"Grandpa, I was wrong!"
Instantly, the wooden sword froze mid-air. The old man turned away, cheeks faintly pink, feigning anger with a huff.
"Hmph!"
"I'll beat you tomorrow. Come eat!"
Kuwajima Jigoro turned toward the halfway cabin, heart swelling at being called "Grandpa."
After raising this boy through thick and thin, he'd waited years for that word.
Tendo chuckled to himself.
The old man was all bark and no bite—his heart was soft.
A single "Grandpa" never failed.
Ah, what a tsundere geezer.
Brushing off his pants, he stood up, already scheming how to ruin Kaigaku's chances of becoming the old man's disciple.
One junior—Zenitsu—was enough.