Demon Slayer: Guardian of the Forest

Under the pale moonlight, Shinichi stood bent over, his upper body bare and glistening with sweat. On his back, he bore a massive spherical boulder nearly ten times his own size.

His breath came in ragged gasps, loud and strained, sounding like a bellows pushed to its limits. Beads of sweat, thick and heavy, rolled down his perfectly sculpted physique—a body honed to perfection through his transformation into a demon.

Six well-defined abs, firm biceps, a sharply contoured V-line, and veins faintly visible beneath his skin made Shinichi the embodiment of physical prowess. Any observer would envy his form. Yet, his face was contorted in pain, his crimson eyes ablaze, his black hair plastered to his head, soaked with sweat. The weight on his back pushed him dangerously close to his limits.

"Grr...!" A guttural growl escaped his throat as his intense exertion triggered his demon instincts. His crimson eyes glowed darker, his fangs grew sharper, and claws extended from his fingers involuntarily.

Just as he teetered on the brink of losing control, a firm but calming voice cut through the night air.

"Shinichi! Hold on! Don't let the demon's power consume you!" roared Master Moriki from atop the boulder, his voice steady and commanding. "The strength you need must come from within, not from the curse in your veins! Just thirty more seconds—endure it! Don't give up!"

Moriki's voice pierced the haze clouding Shinichi's mind. The glow in Shinichi's eyes dimmed slightly, and he gritted his teeth with renewed resolve. "AAAHHHH!" he bellowed, his roar shifting from feral to human, from chaos to clarity.

Finally, the thirty seconds passed. With a resounding thud, the massive boulder hit the ground, creating a deep crater. Shinichi collapsed beside it, his chest heaving violently, his breath ragged but triumphant.

Moriki leapt gracefully from the boulder and retrieved a water flask from a nearby wooden box. He handed it to Shinichi, who took it without hesitation, gulping down its contents.

The flask contained tea brewed from the Wisteria flower—a concoction not for hydration but to suppress Shinichi's demonic essence. For ordinary demons, Wisteria was lethal poison. For Shinichi, it was a lifeline, suppressing the monstrous power within him and allowing him to train like a human.

Initially, Shinichi had been skeptical of Moriki's suggestion to drink Wisteria tea. He'd suspected the old man of trying to poison him. However, after several trials, he discovered that while the tea weakened his demonic strength, it didn't harm him otherwise. Trust in his mentor gradually grew, paving the way for his rigorous training.

To compensate for Shinichi's suppressed power, Moriki devised an extraordinarily intense regimen. What would break an ordinary human in hours was merely the starting point for Shinichi.

Unbeknownst to him, Moriki had scaled up the training to 100 times the difficulty practiced by the Moriki family ancestors. Shinichi, believing this to be standard, developed a profound respect for the family's lineage.

The essence of Forest Breathing lay in harmonizing one's body with nature itself. Every breath had to draw from the immense vitality flowing through the world, channeling it into one's veins, muscles, and even the soul. For Shinichi, achieving this balance as a demon was akin to climbing a mountain of glass barefoot.

Thus began his hellish training.

Carrying a 20-ton boulder for two hours was just the warm-up.

Running a grueling 100-kilometer loop through an oxygen-deprived underground mine once used by the Moriki family.

Towing a 20-meter wooden boat loaded with supplies along the Shallow Wild River, endlessly looping between villages.

Enduring Moriki's modified "Storm Cutter" attack—his Forest Breathing: Sixth Form scaled down just enough to avoid severe injury.

These were just a few of the torturous drills Shinichi faced daily.

Months passed in relentless toil. For Shinichi, each day was a cycle of agony and perseverance. But in just half a year, his transformation was nothing short of miraculous.

The wind ruffled his hair as Shinichi stood tall in a bamboo clearing. His hand, now steady and strong, rested on the hilt of his wooden blade. His eyes were closed, his expression serene. The once-feral crimson glow in his gaze had been replaced by a soft, peach-colored hue—a sign of balance achieved.

Suddenly, the shrill sound of something cutting through the air reached his ears. It was a boulder, launched like a cannonball, hurtling toward him with lethal intent.

Shinichi didn't flinch.

"Forest Breathing: Fifth Form—Soaring Bamboo Strike!"

In an instant, his wooden blade arced upward. A flash of green light surged forward, cleaving the incoming boulder into dust.

As the rock shattered, Shinichi sheathed his blade with practiced ease. Behind him came a slow, steady clap.

"Well done, Shinichi," said Moriki, stepping forward, his face beaming with pride. "You've surpassed every expectation. You've become stronger than any Moriki heir before you. I have nothing more to teach."

Shinichi turned to face his mentor, his smile calm and confident. The transformation was evident. The once-turbulent and reckless youth now exuded an aura of maturity and control. His very presence radiated a harmonious blend of strength and serenity.

"Master, if you keep praising me like that, I might start to get cocky," Shinichi joked. His tone, once sharp and aggressive, now carried a warmth born of trust and growth.

Standing there in the moonlit bamboo forest, Shinichi no longer resembled a demon. His fangs had receded, his claws dulled. Even the faint scent of Wisteria clinging to him felt more like a protective charm than a necessity.

He looked, sounded, and felt human—though deep within him, the battle between man and monster raged on.