The sun had barely risen, yet the Hashira were already up, their bodies aching from Saitama's "training." Even Giyu, who rarely showed emotion, wore a subtle grimace as he stretched his sore muscles.
"This training is insane," Zenitsu whimpered, his legs shaking like bamboo in the wind. "I might die before Muzan even finds us!"
"You'll survive," Sanemi barked, though even he was secretly impressed — and terrified — by Saitama's sheer durability and the way his 'simple' exercises left everyone broken.
Meanwhile, Saitama stood on a cliff's edge, gazing at the horizon. His cape fluttered in the breeze, and for a moment, there was an almost heroic aura around him… until Inosuke ran up and yelled, "OI BALDY! FIGHT ME!"
Saitama blinked. "Huh?"
Without waiting for a response, Inosuke lunged. His twin swords slashed in wild arcs, faster than most could see — yet Saitama just gently stepped aside, making Inosuke trip over his own feet and faceplant into the dirt.
"Maybe train more," Saitama suggested.
"RRGHH!" Inosuke flailed, half buried in the ground.
"Enough playing around," Rengoku called, his voice serious. "There's a storm coming. I can feel it."
---
In the Depths of the Forest
Far away from the training ground, a twisted gathering was taking place. The Upper Moons stood together — Akaza in the center, arms crossed, his usual smug grin replaced with cold focus.
Beside him stood a figure no one had seen before — a woman draped in dark violet robes, her hair flowing like liquid ink, and eyes shimmering like fractured glass. This was Rokuro, Upper Moon Four, the demon with dominion over time.
"Are you sure you can defeat him?" Akaza asked, his tone slightly skeptical.
Rokuro's lips curved into a sinister smile. "I cannot match his power head-on… but power is useless if time itself betrays him."
Akaza grunted, unconvinced. "If you fail, I will fight him myself. And this time… I won't hold back."
Rokuro raised her hand, the air around her rippling like water. "Don't worry. I have no intention of failing."
---
Training Continues - Saitama's Combat Lesson
Back at camp, Saitama stood in the center of a wide clearing, the Hashira surrounding him. This time, they were here not just to spar, but to learn.
"Okay, so… fighting strong enemies." Saitama scratched his chin. "You punch them. Really hard."
"That's it?" Mitsuri blinked.
"Yup."
The silence was deafening.
"That's not how swordsmanship works," Giyu muttered.
Saitama shrugged. "Worked for me."
"Alright then!" Rengoku unsheathed his sword, his flames crackling to life. "Let's see if we can apply our techniques while learning from your absurd strength."
They divided into pairs — Hashira vs. Hashira — all with one rule: fight as if they were facing Upper Moons. Saitama stood back, watching with his usual bored expression, but inside, he was a little curious.
---
Tanjiro vs. Sanemi
Tanjiro's blade flowed like water, seamless and graceful, but Sanemi's wind strikes were brutal and unpredictable, tearing through the air with wild ferocity. Yet through every clash, Tanjiro's senses sharpened.
"Your attacks are fast," Tanjiro panted, blocking a heavy slash. "But they're always angled slightly down. You aim to overwhelm instead of precision cutting."
Sanemi grinned. "Clever brat."
---
Mitsuri vs. Shinobu
Mitsuri's whip-like sword danced through the air, vibrant and elegant, while Shinobu's movements were delicate and precise, aiming for pressure points and poison strikes.
"I wonder," Mitsuri smiled, "Could we combine our styles?"
Shinobu's eyes sparkled with intrigue. "Let's find out."
---
Rengoku vs. Giyu
Fire met water in a beautiful clash of opposing styles. Flames roared, waves crashed, and in the heart of it, both swordsmen smiled slightly.
"We'll need both fire and water to extinguish Muzan's darkness," Rengoku said.
Giyu nodded silently.
---
Observation
Saitama watched it all — the struggle, the sweat, the frustration, and the breakthroughs. It reminded him, just for a second, of when he used to train for real. When becoming strong was a goal, not just a side effect.
"Hmm," Saitama mumbled to himself. "Maybe… this is kind of fun."
---
Nightfall - The First Attack
The peaceful training was shattered when the sky itself seemed to ripple.
Suddenly, Tanjiro froze mid-step — his body refusing to move. Around him, time slowed to a crawl. Zenitsu's terrified scream stretched into a distorted echo, and Mitsuri's sword swing moved like syrup.
In the middle of this frozen world stood Rokuro, her smile predatory.
"So this is the Slayer's training camp," she whispered. "How unfortunate… it ends tonight."
Saitama stood nearby, unaffected.
"Huh?" He tilted his head. "Why's everyone moving so slow?"
Rokuro's smile faltered. "What?"
"Are we playing freeze tag or something?" Saitama walked over to Tanjiro, tapping his shoulder. "Hey, you okay?"
Tanjiro could barely twitch his eyes.
Rokuro's face twisted in confusion. "You're… immune?"
Saitama stared at her. "Are you the bad guy?"
Rokuro hissed. "You could say that."
"Okay." Saitama cracked his neck. "Let's get this over with. I'm missing dinner."
---
End of Chapter 39