"A Lower Moon… is this all there is to it?"
Mr. Cheng Mo looked down at Kamanue, who was twitching and screaming on the ground, a hint of undetectable disappointment in his voice.
But more than that, there was the focused interest of a researcher observing a novel specimen.
"Lightning Release… seems to have a miraculous effect on your regenerative abilities."
He noticed that at the charred, severed shoulder of Kamanue, the granulation tissue was regenerating extremely slowly.
Moreover, each attempt to grow was scorched black by the lingering blue electrical sparks.
It was as if this energy was inherently antithetical to a demon's immortality.
This was completely different from his previous experiences of slaying demons with a nichirin blade or fighting with a Breathing Technique.
The energy of the Breathing Technique was more like a burst simulating natural forms.
The nichirin blade, on the other hand, destroyed demons fundamentally by harnessing the power of the sun.
Lightning Release Chakra, however, was like a more violent, more destructive energy.
It directly inhibited and even destroyed the demon's regenerative structure on both physical and energetic levels.
"An interesting discovery," Cheng Mo murmured to himself.
Tanjirou and Nezuko had already poked their heads out of the train car.
Tanjirou's face still showed lingering shock, but even more, it revealed his awe at Mr. Cheng Mo's immense power.
Nezuko, on the other hand, glared fearfully and angrily at the screaming Kamanue on the ground.
Cheng Mo no longer paid attention to the reactions of others; his focus was entirely on Kamanue.
He squatted down, and tiny, controllable electric arcs once again danced between his fingers.
"Come, let's try."
He seemed to be speaking to Kamanue, yet also to himself.
"What is the difference in the inhibitory effect on regeneration with different voltages and current intensities…"
"Will nerve conduction be completely destroyed… and where is the limit of pain feedback…"
As he spoke, the electric arc on his fingertip once again touched Kamanue's other intact arm.
"No! Don't! Spare me! Help…"
Kamanue was scared out of his wits, begging piteously, but before he could finish his words, he was replaced by even more intense screams of pain.
"Ah ah ah ah!!!!"
Sizzle! Poof… The faint sound of lightning scorching and the smell of charred flesh permeated the air.
Cheng Mo's eyes were focused, like the most rigorous scientist, carefully observing the changes in the wound.
He observed Kamanue's reaction, feeling the consumption of energy.
He was completely immersed in the study of the interaction between this unknown energy and the demon body.
That calm, almost ruthless demeanor, that gaze as if disassembling an inconsequential piece of machinery, and Kamanue's inhuman, hair-raising, mournful screams, formed an incredibly bizarre and terrifying scene.
Tanjirou and Nezuko watched, their faces pale, instinctively huddling closer to each other.
Although they knew the opponent was an evil demon, a kin of the Demon King who murdered their family… Mr. Cheng Mo's calm, almost cruel "experiment" still sent shivers down their spines.
Giyu Tomioka had completely turned around, watching in silence.
His gaze lingered for a moment on Cheng Mo's violent yet restrained Lightning Release power, then fell upon Kamanue, who was still screaming and regenerating extremely slowly.
A deep tremor flashed in his fathomless eyes.
This power… And the scouting demon hiding further back in the woods was already scared out of its wits.
It had witnessed with its own eyes how Lower Moon Kamanue-sama was torn apart and tormented like an infant before that terrifying man, with even regeneration becoming so difficult!
Escape! It must escape! It must deliver the message to Muzan-sama!
It turned to flee into the dense forest as a shadow.
However, a figure, like a ghost, silently blocked its path.
Giyu Tomioka held his nichirin blade, still in its sheath, and simply looked at it calmly.
The icy killing intent emanating from him was more biting than the mountain wind of this winter night.
"Gah…!"
The scouting demon let out a strange cry of fear, its eyeball on its forehead spinning wildly, almost bulging out of its socket.
By the carriage, Cheng Mo's experiment continued.
He was like someone disassembling a complex machine, calmly testing the inhibitory effect of Lightning Release energy on different body parts and different concentrations of demon blood.
Kamanue's screams had become hoarse and weak, his aura rapidly declining, his body covered in charred pits and lacerations, and regeneration had almost completely ceased.
Lightning Release Chakra… its priority in restraining demons was far higher than anticipated.
Cheng Mo reached a preliminary conclusion, and his evaluation of the Chakra system once again increased.
It seems he needs to focus more on this aspect of cultivation.
He stopped, throwing the dying Kamanue, who was emitting black smoke and tiny electrical arcs, onto the snow like trash.
The demon could only twitch slightly, no longer having the strength to even scream.
Cheng Mo flicked his hands, as if shaking off non-existent blood, and the lightning around him quietly receded.
He looked up, his gaze falling upon the trembling scouting demon, who was being blocked by Giyu Tomioka, his eyes calm and unperturbed, yet making the demon feel as if it had fallen into an ice abyss.
"Mr. Giyuu, leave this one alive," he said, his voice showing no trace of the cruel experiment he had just conducted.
"It has other uses."
Giyu Tomioka frowned slightly, looking at Cheng Mo with a questioning gaze.
But he still slowly withdrew his nichirin blade as instructed.
He believed Cheng Mo must have a deeper meaning in doing so.
As soon as the scouting demon gained freedom, it almost scrambled to escape backward.
But as it moved, it heard Cheng Mo's cold voice ring out again.
"Take one more step, and your fate will be the same as the one just now."
The scouting demon's body instantly stiffened, as if doused with ice water.
Fear nailed it to the spot, unable to move.
Cheng Mo no longer looked at it, but turned his gaze to Tanjirou, who still looked a bit pale.
"Tanjirou."
"Yes! Sir!" Tanjirou jolted, immediately straightening his body.
He instinctively pulled Nezuko closer, protecting her more tightly.
Cheng Mo's hand seemingly casually reached into his embrace, but in reality, with a thought, he took out a simple yet coldly gleaming short military knife from his compass space.
He flicked his wrist, and the military knife cut a short arc.
With a "clunk," it accurately plunged into the snow in front of Tanjirou's feet.
"Go," Cheng Mo's voice was devoid of any ripple, as if giving instructions for the most ordinary task, "Cut off its head."
"Wh-What?!"
Tanjirou's eyes widened suddenly, looking at Cheng Mo in disbelief, then abruptly at the demon, who, though terrified, still exuded a dangerous aura.
He… was to kill a demon alone?
"Sir… I…" Tanjirou's voice was a bit dry.
"What's wrong?" Cheng Mo's voice showed no emotion.
"Facing the demon that slaughtered your family, you don't even have the courage to swing your blade? Is your revenge just empty words?"
These words were like a sharp thorn, piercing deeply into Tanjirou's heart.
The image of his family's brutal death instantly flooded his mind, and immense grief and anger instantly overwhelmed that trace of hesitation.
He suddenly bent down and snatched the short knife from the ground.
The cold touch of the hilt came, carrying a strange sense of heaviness.
Nezuko, frightened, clutched her brother's sleeve tightly, making faint "mm-mm" sounds, her small face full of panic.
Giyu Tomioka's brow furrowed almost imperceptibly.
But he looked at Cheng Mo's calm profile and ultimately remained silent.
He only tightened his grip on his sword hilt slightly, adjusting his body to a stance ready to intervene at any moment.
Cheng Mo ignored Tanjirou's shock and turned to the scouting demon, who was almost scared out of its wits.
His tone remained flat, yet carried a chilling ruthlessness.
"You heard me. Kill this boy in front of you, and I will let you go. This is your only way out."