The Shadow-Stealing Demon That Shouldn't Exist

The pleasure of revenge did not linger in Moyu's heart for long. After he slew the Hand Demon, the Azure Eyes within his heart grew colder and calmer. The Hand Demon's demise seemed to have intimidated the other demons in the area. For two days straight, Moyu encountered nothing but weak fodder, most of whom were cut down by flashes of azure steel the moment they met him, without even time to scream.

[Ordinary demons slain ×18. Side Quest progress: 42/?]

The system's notification tone mechanically recorded the slaughter, but Moyu's mind was elsewhere. As he cleared out the demons along the way, he extended the perception range of his Six Eyes to its limit, carefully scanning every corner of Mount Fujikasane. The Hand Demon's hateful, mocking words before its death, as well as its strength, which far exceeded that of an ordinary demon, gave Moyu a vague feeling that this mountain of trials might not be as simple as it appeared. In the original story, the Hand Demon had been the "boss" of this trial, but since this world now had him as a variable, it was not impossible for other anomalies to appear.

His goal was to find stronger prey and investigate any possible irregularities.

At dusk on the third day, as Moyu passed through a mist-shrouded swamp, his Six Eyes picked up an extremely faint fluctuation of energy. It was not powerful enough to draw attention; rather, it seemed deliberately restrained, like a venomous snake lurking beneath the mud, with cold patience and deadly killing intent. From the direction of the fluctuation came another familiar presence—fiery and tenacious, but somewhat hurried and weary.

It was Tanjiro!

Moyu's gaze sharpened. His figure instantly became a pale blue afterimage and slipped soundlessly into the thick fog.

Deep in the swamp, Tanjiro was locked in a grueling battle.

His opponent was not a massive, strength-based demon, but a bizarre creature with a long, thin body and dull gray skin that seemed to blend into the surrounding shadows. Its attacks were exceedingly treacherous. Rather than confronting Tanjiro head-on, it constantly used the swamp's terrain and thick fog to conceal itself, launching ambushes from impossible angles. Its arms could stretch and twist like rubber, and its fingertips were as sharp as awls, targeting vital points such as Tanjiro's joints, eyes, and throat.

"Water Breathing, Fourth Form: Striking Tide!"

Tanjiro swung his blade to deflect a vicious thrust from the side, the blade colliding with the spray with a muffled sound. He was breathing hard, and sweat beaded on his forehead. The demon was too cunning: every attack ended the moment it landed, and it never lingered. Several of Tanjiro's fierce counterattacks struck empty air or were evaded with the demon's bizarre movements. Worse still, the demon seemed able to interfere with his sense of smell to some extent. The air was filled with the stench of the rotting swamp and a sickeningly sweet, bloody odor emitted by the demon itself, making it difficult for Tanjiro's keen nose to pinpoint its location.

"Hee hee hee... It's no use, boy." The sinister laughter came from every direction in the fog. "Your breathing's starting to go out of rhythm. Keep struggling. Once you run out of strength, it'll be time for me to enjoy my meal."

Another gray arm shot out of the mud beneath Tanjiro like a venomous whip, aiming straight for his ankle. Tanjiro barely managed to leap aside, and a deep hole was punched into the ground where he had stood.

This can't go on! Tanjiro thought anxiously. He tried to use a more powerful form, but the demon gave him no chance to build up strength or lock onto his target. The nascent form of Sun Breathing required a steadier rhythm and a stronger burst of power. Under the present circumstances, with the demon constantly harassing him and proving difficult to pin down, forcing himself to use it would only drain his stamina faster.

Just as Tanjiro blocked another attack from above, with his previous strength spent and his next burst yet to come, a gray shadow came at him like a specter from his blind spot, aiming straight for the center of his back! The strike was so swift and vicious that Tanjiro could no longer fully evade it!

At that critical moment—

"Azure Flow Breathing, Zero Form, First Style: Vortex Slash, modified."

A calm voice rang out, accompanied by a spiraling arc of azure blade energy that sliced through the air! Rather than striking the shadowy demon directly, the blade energy cut precisely into the space between Tanjiro and the attacking arm. Its powerful rotating field instantly warped the attack's trajectory, and the deadly blow grazed the hem of Tanjiro's clothes before snapping a nearby dead tree in half.

"Moyu!" Tanjiro was both startled and delighted.

Moyu's figure slowly emerged from the thick fog. His azure eyes shone like two lamps in the dim light, fixed on a seemingly empty corner of shadow.

"Hiding is meaningless," Moyu said calmly, holding his Nichirin Blade level. "Before these eyes of mine, the flow of your energy is like a torch in the dark."

The shadow twisted, and the Shadow-Stealing Demon revealed itself. Its deathly pale, pupil-less eyes stared fixedly at Moyu, and for the first time, uncertainty and suspicion appeared on its face. "You... you can see me?"

It was extremely confident in its ability to conceal itself. Even a Hashira-level swordsman could easily fall victim to it without knowing its abilities. Yet this newcomer had seen through its disguise at a glance?

"Not only can I see you," Moyu said, advancing step by step as the azure glow at his blade's tip grew brighter, "I can also see the nodes where energy flows through your body, the signs of your muscles tensing, and where... you'll land next."

Before he finished speaking, Moyu moved. He planted a foot, and his figure blurred. Rather than charging in a straight line, he closed the distance in an instant with footwork that held a profound rhythm—the Flowing Cloud step, which combined Shave with a Breathing Style.

The Shadow-Stealing Demon was horrified. It retreated rapidly, waving both arms frantically as dozens of spikes formed from shadow energy shot at Moyu like a torrential rain, trying to stop his advance.

Yet within the Six Eyes' field of vision, the trajectories, speed, and weaknesses of those attacks were perfectly clear. Moyu did not even use a complicated form. With only a slight movement of his wrist, his Nichirin Blade traced several simple, efficient arcs.

Ssh, ssh, ssh—!

Where the azure blade flashed, the shadow spikes melted and disintegrated like ice and snow in sunlight. Moyu's advance was not slowed in the slightest.

"How is that possible?!" The Shadow-Stealing Demon finally felt fear. Its attacks had been neutralized so easily?

"Tanjiro," Moyu said as he closed in, "watch carefully. Against an opponent who excels at hiding and hit-and-run tactics, the key is to restrict their room to move and anticipate their actions."

As he spoke, Moyu changed his swordwork. Instead of precise, point-to-point strikes, he swept out a curtain of azure blade light—a variation of Water Breathing, Second Form: Water Wheel! Unlike Tanjiro's wide, sweeping movements, however, Moyu's Water Wheel covered a smaller area and spun faster. Its blade light fell as densely as rain, subtly sealing off several directions in which the Shadow-Stealing Demon might dodge.

The Shadow-Stealing Demon was forced to slide backward, trying to merge into the shadows once more. But Moyu's Six Eyes remained locked on it, and the unmistakable energy signature on its body had nowhere to hide from his sight.

"It's no use," Moyu said coldly. Seizing the brief opening when the Shadow-Stealing Demon's previous strength had faded and its next burst had yet to come, he accelerated again!

"Azure Flow Breathing, Zero Form, Second Style: Mirror Dissection, minor application!"

This time, the blade's tip did not point at the demon's body, but lightly touched a patch of air in front of it. A strange vibration spread outward. The shadow energy around the Shadow-Stealing Demon rippled violently, like water disturbed by a thrown stone. Its concealment was forcibly broken, and it staggered, leaving a huge opening!

Now's the time! Though astonished by Moyu's exquisite control, Tanjiro's combat instincts made him seize the opportunity at once.

"Water Breathing, First Form: Water Surface Slash!"

His burning fighting spirit poured into Water Breathing, Tanjiro brought his Nichirin Blade straight down toward the Shadow-Stealing Demon's face with unstoppable force! The slash was swift and fierce, catching the opponent at the instant it lost its balance.

The Shadow-Stealing Demon hurriedly raised a twisted arm to block.

Clang!

A piercing clash rang out. Tanjiro's slash, which held all his strength, had actually been blocked! The Shadow-Stealing Demon's arm was unimaginably hard.

But Moyu's attack followed close behind. The instant the Shadow-Stealing Demon blocked Tanjiro's strike, its attention fully drawn to him, Moyu's blade moved. There was no dazzling brilliance, only an utterly restrained thread of azure that flashed past, seemingly swallowing even the surrounding light.

"Whirlpool Slash: Extreme!"

The blade passed over the joint of the arm the Shadow-Stealing Demon had used to block Tanjiro. There was no head-on collision, only high-frequency vibration and cutting. Under the combined force of the structural weakness precisely located by the Six Eyes and the spiraling destruction of Breathing Cursed Energy, the hard arm was severed at the elbow!

"Argh!" The Shadow-Stealing Demon roared in pain, its eyes finally filled with fear. These two boys, especially the blue-eyed one, were terrifying! Its strongest concealment and defense were useless before them!

It completely lost the will to fight and turned, intending to flee into the depths of the swamp.

"You can't escape." Moyu's voice was like a death sentence.

The Six Eyes had already calculated all its escape routes. Moyu's figure flickered, and he cut off its retreat at a speed greater than the Shadow-Stealing Demon's.

"Pay the price for hurting my companion."

His Nichirin Blade rose, azure light gathering along its length like a river of stars falling from the night sky. This time, Moyu combined the spiraling cutting force of Vortex Slash with the precise deconstructive power of Mirror Dissection, creating a strike focused even more heavily on absolute destructive power.

"Azure Flow Breathing, Zero Form, Third Style: Myriad Forms Mimicry, Disintegration!"

The blade light fell, not as a slash, but like an invisible sledgehammer crashing down! The air around the Shadow-Stealing Demon seemed to freeze. Then the shadow energy covering its body, its muscles, and its bones began to groan under the strain from within, breaking apart inch by inch! This was the reconstructive power of Myriad Forms Mimicry applied in reverse, turned into a collapse triggered at the molecular level!

Pff—

Like a bursting abscess, the Shadow-Stealing Demon could not even finish a single scream before its entire body exploded in the azure storm of energy. It became black ash scattered through the air, which was then swallowed by the swamp fog.

[Mutated demon "Shadow-Stealing Demon" slain. Side Quest progress: 43/? (special target completed)]

[Rewards: Coins +3,000, Nichirin Blade Resonance +15%]

The battle was over, and silence returned to the swamp, broken only by Tanjiro's slightly hurried breathing.

"Moyu! Thank you!" Tanjiro sheathed his blade and spoke gratefully, still shaken. "That guy was too hard to deal with. I don't know what I would've done without you."

Moyu shook his head, though his gaze remained grave as he scanned the surrounding fog. "It was nothing. Tanjiro, have you encountered this type of demon before?"

Tanjiro thought back carefully, then said with certainty, "No! Among the types of demons Mr. Urokodaki told us about, he never mentioned one that could completely merge into the shadows and interfere with your sense of smell."

Moyu crouched down and gathered a little of the ash left behind when the Shadow-Stealing Demon dissipated on his fingertip. His Six Eyes carefully analyzed the energy residue within it. "Its energy structure is very unusual, different from the murky power the Hand Demon accumulated by devouring others."

He stood and looked toward the depths of Mount Fujikasane. "Two special individuals with strength far beyond ordinary demons have appeared in succession. That's not normal. Some change we don't know about may have occurred on this mountain."

Tanjiro also sensed the seriousness of the situation. "What do we do, then? There are other people taking the trial..."

"It'll be more efficient if we split up," Moyu decided. "Over the next few days, I'll focus on investigating this mountain and looking for any other sources of these anomalies. Tanjiro, continue as planned, but be even more careful. If you encounter a powerful enemy you can't handle, make your own safety your first priority. You can make some noise, and I'll come as quickly as I can."

Tanjiro nodded firmly. "I understand! You be careful too, Moyu!"

The two parted again. Moyu headed in the direction from which the Shadow-Stealing Demon had appeared, pushing the perception of his Six Eyes to its limit. Like the most precise radar, he scanned Mount Fujikasane inch by inch: its soil, its air, and even the flow of energy.

Over the next two days, Moyu cleared out the ordinary demons he encountered along the way with great efficiency, but found no more special beings on the level of the Hand Demon or the Shadow-Stealing Demon. He also carefully investigated several points with abnormal energy, but most were simply natural phenomena caused by larger gatherings of demons, or veins of rock containing certain special minerals. He found no definite, man-made source of the mutations.

[Ordinary demons slain ×25. Side Quest progress: 68/?]

On the night of the fourth day, Moyu stood atop a relatively high cliff, looking down at Mount Fujikasane beneath the night sky. The mountain wind stirred the loose strands of hair on his forehead, and sparse starlight was reflected in his azure eyes.

"No more discoveries... Could they really have just been isolated cases? Did those two demons happen to undergo special mutations?" Moyu pondered. The Hand Demon had accumulated its strength by devouring swordsmen over a long period, while the Shadow-Stealing Demon had unusual abilities. Statistically speaking, it was not impossible for individual mutants to appear among demons. Perhaps he was overthinking it?

He put those thoughts aside, his gaze growing resolute once more. Whatever the case, improving his own strength was always the best way to deal with unknown risks. With three days left, he would slay as many demons as possible, accumulate Coins and experience, and ensure the safety of Tanjiro and the other surviving trial participants.