The Butterfly Mansion was awake before the sun.
Lanterns glowed along the courtyard paths, and the air smelled of mist, medicine and sweat. Demon Slayers were already shouting, groaning, stretching — preparing for Hashira Training Day 1.
But one man stood in the center like a general on a battlefield.
Tengen Uzui.
His bare chest gleamed with sweat, muscles sharp as stone, his one remaining arm wrapped in bandages — yet he radiated power like a living thunderbolt.
"LISTEN UP, MAGGOTS!" he yelled. "Hashira Training begins now! If you don't become flashy, you'll die in the next battle — so TRAIN LIKE YOUR LIFE DEPENDS ON IT!"
Zenitsu shrieked. Inosuke roared. Tanjiro nodded eagerly. And Jinwoo…
Jinwoo simply cracked his neck, unimpressed.
Tengen smirked. "Oh? The silent dark guy thinks this will be easy? I'll fix that."
But he had no idea.
---
DAY 1 — RUN UNTIL YOUR SOUL SCREAMS
Tengen raised his arm.
"RUN! Until your legs catch on fire!"
Dozens of Demon Slayers sprinted across the courtyard, collapsing, vomiting, gasping for air — but Tengen never stopped them.
Zenitsu cried the entire run. Inosuke sprinted on all fours, yelling victory chants. Tanjiro kept smiling through pain.
And Jinwoo?
He jogged.
Calm. Relaxed. Breathing normally but faster than others.
Tengen narrowed his eyes. He picked up a rock and threw it — directly toward Jinwoo's head.
Jinwoo tilted slightly — the rock missed by a hair.
Tengen grinned. "Nice reflex. But I'm not done."
He threw five more stones — impossibly fast.
Jinwoo dodged them all without losing pace.
Tengen burst out laughing. "That's what I WANT! Bring it on, dark bro!"
Zenitsu cried harder watching them. Inosuke tried to compete but tripped instantly.
---
DAY 2 — SWORD SWINGS
Hundreds of wooden swords lined the field.
Tengen pointed. "Swing the sword 1000 times. If you stop, I'll beat you myself."
Everyone began.
Tanjiro pushed through pain, breath steady. Inosuke turned it into a screaming competition. Zenitsu wept but kept swinging.
Jinwoo…
barely used strength.
He swung like he was brushing dust off a table.
No sweat. No fatigue.
Tengen walked up behind him silently — testing.
SWISH —!!
Jinwoo blocked Tengen's wooden sword without turning around.
Tengen's grin widened so big it looked insane.
"That's my boy."
---
DAY 3 — PUSH-UPS & BODY TRAINING
Demon Slayers collapsed one by one. Wrists cracked. Muscles tore. Bodies trembled.
Tanjiro kept whispering: "I can do more… I can become stronger…"
Zenitsu begged for death. Inosuke screamed in victory every time he collapsed.
Jinwoo?
He wasn't even breathing hard.
He stared at the ground like the training was… boring.
He is doing pushup up easily, even in one handed
Tengen finally snapped.
"You. Spar with me tomorrow. A real fight."
Jinwoo raised an eyebrow. "Fine."
Zenitsu fainted. Tanjiro smiled nervously. Inosuke cheered.
---
DAY 4 — FOOD BREAK
The courtyard suddenly smelled amazing — rich spices, grilled meat, vegetables.
Three beautiful women walked in with trays.
Makio. Suma. Hinatsuru.
Tengen's wives.
The entire training ground froze. Every man stared.
Zenitsu collapsed in tears. Inosuke immediately challenged them to arm wrestling. Tanjiro politely bowed.
And Jinwoo…
Jinwoo blinked slowly.
…He has three wives?
System notification appeared:
> Emotional Stability — Broken
Confusion — 100%
Jinwoo looked at Tengen silently.
Tengen winked. "Having one wife is not FLAMBOYANT enough."
Jinwoo stared at him. Then, very quietly —
"…respect."
Everyone else fainted from shock.
During the break, while others ate desperately, Jinwoo sat quietly, watching.
Tanjiro shared food with everyone. Zenitsu begged for Mitsuri. Inosuke ate like a wild boar.
And Tengen laughed with his wives, full of love.
Jinwoo felt the system activate again.
> Honor scanning… Uzui Tengen — Honor: HIGH (Loyalty • Love • Pride)
Jinwoo's eyes softened.
"Strong. Flashy. But a good man."
He summoned a shadow silently — a medium-tier Orc Knight.
It bowed respectfully and slipped into Tengen's shadow, completely unnoticed.
Protection assigned.
---
SPARRING MATCHES BEGIN
Tengen clapped once.
"Everyone who passed physical training will now SPAR. First up — KAMADO TANJIRO!"
Tanjiro stepped forward, breathing sharply. Even exhausted, his spirit blazed.
Tengen drew a wooden blade. Tanjiro raised his Nichirin blade.
And—
BOOM!!!
They clashed like thunder.
Tanjiro's technique vs Tengen's overwhelming physical power. Tanjiro flew back again and again — but kept getting up.
Tanjiro: "I can still stand!" Tengen: "That's how you become FLASHY!"
At the end, Tanjiro collapsed—but smiling.
Tengen placed his hand on Tanjiro's head. "You pass."
Zenitsu screamed in disbelief. Inosuke punched a wall in jealousy. Jinwoo nodded slightly — proud.
Then…
Tengen pointed his sword at Jinwoo.
"Your turn, dark bro."
---
JINWOO VS TENGEN
Everyone backed away.
Jinwoo stepped into the arena with no sword. Tengen tightened his grip.
"You're strong — but physical strength is MY territory. Let's see what you've got."
Jinwoo lifted one hand. "Come."
Tengen blurred — faster than lightning despite one arm. Jinwoo leaned — dodging every strike casually.
CRACK — BOOM — SWISH —!!
Ground broke. Air exploded.
Jinwoo didn't attack once — just watched.
Tengen grinned like a madman.
"You can dodge. But can you HIT?"
He leaped high — spinning, fierce, unstoppable.
Jinwoo finally moved.
ONE PUNCH.
Not to hurt — just to test power.
The shockwave ripped the ground. Tengen was blasted backward, crashing across the courtyard.
Everyone froze.
Tengen stood back up, spat blood — and laughed proudly.
"You pass… you MONSTER!"
Jinwoo nodded respectfully.
"You're strong too. Even with one arm."
ZENITSU AND INOSUKE: "WHAT KIND OF TRAINING WAS THAT?!"
---
THE FINAL RESULT
Tengen raised his voice.
"Only those who passed all 4 days may leave to the next Hashira!"
He pointed:
"KAMADO TANJIRO — PASS! SUNG JINWOO — PASS!"
Zenitsu sobbed dramatically. Inosuke swore revenge. Jinwoo and Tanjiro bowed.
Tengen smirked at Jinwoo.
"You'll become even flashier. I guarantee it."
System Level Up
A digital sound echoed in Jinwoo's ears.
> [Training Complete — Hashira Progress: 1/7]
Reward Granted: 560,000 XP
LEVEL UP!
Current Level: 127 → 129
Jinwoo's eyes glowed purple for a second.
Zenitsu yelled, not understanding.
"WH-WHAT WAS THAT LIGHT!? DID HE JUST POWER UP LIKE A FINAL BOSS!?"
Inosuke screamed.
"HE'S EVOLVING!!"
Tanjiro smiled innocently.
"Congratulations, Jinwoo-san! Even if I don't understand… I can tell you became stronger."
Jinwoo looked at him, and for the first time, softly replied—
"Yeah… thanks."
Jinwoo noded And silent — the shadow inside Tengen saluted him.
He walked away without ever knowing.
---
DEPARTURE — NEXT HASHIRA
Tanjiro carried his sword. Jinwoo walked beside him in silence.
The world around them turned calm — but tension rose again as they approached another training ground.
A single young Hashira stood there — silver eyes cold, posture perfect, surrounded by exhausted Demon Slayers.
He didn't even look up as Jinwoo and Tanjiro arrived.
Muichiro Tokito.
"Line up," he commanded softly. "If you came here, you're already behind."
Tanjiro gulped nervously. Jinwoo stared silently.
The Mist Hashira finally glanced at Jinwoo…
"…your aura's heavier again."
Jinwoo smirked.
"Let's begin."