Nae collapsed to the ground, her gaze fixed on the spot where the demon had vanished, breathing heavily not from exhaustion, but from fear.
After a moment, she turned towards Hatsune, flashing a proud smile and making a V-sign with her fingers, as if to say, "See? I told you I could protect you."
Unbeknownst to her, a dark figure leapt from behind a nearby rock, covering a good ten meters in mid-air—a Bouncing Demon.
Hatsune had anticipated this.
Sending Nae after the other demon wasn't just to test her strength but to draw out any hidden threats. This creature took the bait.
However, he hadn't expected this demon to possess such an ability.
"Ice Breathing, Sixth Form: Phantom."
Hatsune vanished from the stone platform, leaving a trail of afterimages that converged near Nae.
Before she could fully comprehend, Hatsune stood behind her.
"What incredible speed! Hatsune, what kind of breathing technique is this? It's so elegant. Wait, why is it so cold?"
Nae hadn't noticed the danger yet. As she turned, struggling to rise from the ground, a sudden chill gripped her.
Hatsune gripped the scabbard with his left hand, flicking open the guard with his thumb. His right hand grasped the hilt, poised to draw the sword.
"Ice Breathing, Fifth Form: Swift Ice Pierce."
A blinding flash of white light erupted. Instinctively, Nae shut her eyes. A sharp, piercing sound, akin to the prelude of fireworks but far sharper, pierced the air.
Swift Ice Pierce was Hatsune's quickest and most precise move, ideal for sudden confrontations.
The Nichirin Blade pierced through the Bouncing Demon's palm in mid-air, though it only grazed the hand.
In that brief standoff, both parties recognized a formidable adversary.
To Hatsune's surprise, the Bouncing Demon used the blade for support, pivoting its legs, gripping the blade with its feet, and extracting its hand from the frozen blade. It executed a 180-degree backflip, landing gracefully a few meters away on open ground.
It landed soundlessly, standing erect in the moonlight.
It resembled the flawless landing of a gymnast in competition.
Such lightness, agility, and frightening flexibility.
Finally, Nae noticed the Bouncing Demon, realizing that Hatsune had just saved her. She quickly rose from the ground, brandishing her Nichirin Blade, standing shoulder to shoulder with Hatsune.
In the moonlight, they could finally behold the demon's visage.
It too had a shaved head, a bare chest, and wore only tattered pants—likely its last remnants of humanity.
Its muscles were lean and tightly wound, devoid of excess flesh, with smooth, glistening skin as if oiled. Its legs were sinewy, with well-defined muscles that resembled springs coiled beneath its skin.
Its streamlined physique minimized air resistance, while its powerful lower limbs enhanced its jumping prowess.
The mutation in its blood had not only bestowed unique abilities but also gradually transformed its appearance.
It was now a mutated demon. How many such powerful mutations lurked on Mount Fujikasane? The final test of the Demon Slayer Corps was indeed a perilous trial.
"What... what is this creature?"
"A demon. A mutated one."
The Bouncing Demon examined the frost emitting from its injured palm, then glanced at the two before it.
Deciding it couldn't best Hatsune, it turned, bent its knees, and leapt ten meters into the air, vanishing into the distant forest.
"This..."
Nae gaped, incredulous at the Bouncing Demon's maneuver.
She hadn't witnessed its attack earlier, but seeing it now, she was stunned, her mouth agape until the demon vanished into the night. Slowly, she regained her composure, turning to Hatsune beside her.
Moments ago, it likely intended to ambush her from mid-air. If Hatsune hadn't intervened, she... Nae couldn't bear to contemplate the outcome.
As the Bouncing Demon faded from view, Hatsune sheathed his Nichirin Blade, withdrawing his gaze from the disappearing figure. He casually remarked, tilting Nae's chin up to close her gaping mouth.
"Still hungry? Now you want to eat people?"
Her teeth clicked shut audibly.
Nae shivered, snapping out of her stupor, and caught up with Hatsune, eager for answers. "What... what was that thing just now?"
Hatsune didn't reply immediately. Nae already knew the answer—she sought confirmation.
"Was that a demon? How could a demon look like that?"
The two returned to the stone platform in silence. Nae looked at Hatsune expectantly, yearning for a plausible explanation, her ample chest pressing against his arm.
Hatsune shifted his arm subtly.
Nae hadn't seen demons before, but she had heard stories from her sister, and she had imagined them.
"It must be a mutation. The book mentions that when demons become desperate, they sometimes turn to cannibalism. This can trigger mutations in their blood. Demons are unpredictable creatures to humans, full of unknowns."
Initially, Hatsune had intended this trial to gauge his training progress. Surviving seven days unscathed was an achievement in itself, especially with Nae at his side—a treasure he couldn't fathom how he'd acquired. Moreover, he'd saved her just now despite planning to use her as bait, a departure from his usual methods.
"By the way, earlier I heard you using a breathing technique called 'Love Breathing.' Is it a derivative of one of the five main techniques?"
Nae nodded. "It's derived from Flame Breathing. Flame Breathing requires a unique body temperature for practice. The women of our clan have strong heart and lung functions, large appetites, and fast blood circulation, resulting in slightly elevated body temperatures."
Among the five main breathing techniques, Water Breathing had the most practitioners due to its simplicity and inclusivity. Flame Breathing demanded robust heart and lung functions and higher body temperatures.
Thunder Breathing prioritized speed and necessitated exceptional leg strength.
Stone Breathing relied solely on physical power, requiring top-tier physical fitness from its practitioners—thus, it boasted the fewest followers.
Wind Breathing also had few practitioners, demanding robust upper body strength to wield the Nichirin Blade while launching wind slashes.
Derivatives—more accurately, reduced or diluted techniques—failed to maximize the five main techniques due to physical limitations. Only four people stood atop the five main techniques: Himejima Gyomei, the Stone Hashira; Sanemi Shinazugawa, the Wind Hashira; Kyojuro Rengoku, the Flame Hashira; and Giyu Tomioka, the Water Hashira.