Inside the classroom—
For some reason, Kurenai Yuhi and Rin Nohara started talking about training. Kurenai shared how she had begun working hard and doing morning exercises.
"What? You've started morning training too? And with Shiro Akira? Sugoi! Looks like I can't slack off either! I'll join you tomorrow!"
Rin said in surprise.
"Of course! Let's all do it together!"
Kurenai smiled as she held Rin's hand.
"So even Kurenai has started working hard… then I definitely can't slack off!"
Not far away, Asuma Sarutobi had been paying attention and overheard their conversation, silently making up his mind.
"What? Rin is going to start morning training too?"
Obito Uchiha focused entirely on Rin. Hearing her decision, he suddenly felt a sense of urgency. Maybe… I should start working harder too?
Many others in the class had similar thoughts.
When people stronger and more talented than you are working hard—what right do you have to keep lying flat?
As time passed, with Kurenai, Rin, Asuma, Obito, and others gradually joining morning training and additional practice, the entire class began to "roll."
Everyone started consciously increasing their training time and intensity.
It was as if an invisible force was pushing them forward, filling them with urgency.
This atmosphere soon spread to other classes, grades, and eventually the entire academy.
A new wave of intense competition was forming.
…
Inside the Hokage's office—
Hiruzen Sarutobi quickly received reports from the academy about this growing trend.
After learning the cause, he smiled knowingly.
"Heh… this is a good thing."
"Seems like the power of example is quite strong."
Recently, Asuma had been training diligently—without any supervision.
He even took the initiative to train extra.
Under such effort, his strength was improving rapidly.
Hiruzen felt deeply satisfied seeing this.
…
In the blink of an eye, another week passed.
Shiro Akira's Exchange System had finally cooled down again.
He rubbed his hands excitedly, took out a copied scroll of Lightning Release: Thunder Sphere Technique, and silently muttered:
"Exchange!"
The scroll vanished from his hand.
At the same time, a scene appeared in his mind—
…
Near a mountain forest—
Kokushibo stood above the kneeling Kaigaku.
Around them lay five or six fallen members of the Demon Slayer Corps.
Each corpse was mutilated, severed into multiple pieces.
Blood and limbs were scattered across the ground, staining everything within a ten-meter radius red.
"Please!"
Kaigaku struggled, clutching Kokushibo's leg, begging in terror, "Give me a chance! Spare me! I'll join you—I'll become a demon! Please!"
"Oh?"
Kokushibo raised a brow slightly.
At that moment, he seemed to see his former self in Kaigaku.
The same desperation.
The same desire to survive.
The same unwillingness to accept death.
"I see… You remind me of my past self."
Kokushibo spoke calmly. "Since you beg me, I'll give you a chance. Swallow this drop of blood. Whether you survive… depends on your fate."
He cut his finger and forced out a drop of blood.
"Thank you! Thank you!"
Kaigaku was overjoyed. He had hope—he would live.
He stared greedily at the blood and opened his mouth.
Drip—
The blood fell directly into his mouth.
At that exact moment—
A scroll suddenly appeared out of nowhere and dropped in front of him.
"Hm?"
Kokushibo's eyes narrowed as he instantly grabbed it. What is this? Where did it come from?
He could clearly sense that it had appeared out of thin air—extremely strange.
"AAAAAAH!!!"
Suddenly, Kaigaku screamed.
His body began to distort violently under the influence of the demon blood. Flesh bulged and twisted uncontrollably.
"No! No! My body… what's happening?! NO!!!"
At the moment the scroll appeared, Kaigaku clearly felt his strength—refined through breathing techniques—vanish.
His physique regressed to that of an ordinary human.
Demon transformation was not something just anyone could endure.
If he had retained his original strength, he might have survived the process.
But now, weakened—
His body couldn't withstand the transformation.
His flesh swelled uncontrollably, mutating beyond recovery.
In the end, he expanded into a grotesque sphere over a meter wide—
"Boom!"
—and exploded into a shower of blood and flesh.
Kokushibo had already retreated over ten meters the moment he sensed something was wrong.
Watching the aftermath, he clicked his tongue in annoyance. "Useless. I thought you might succeed."
A waste of his time.
But recalling Kaigaku's final words, his gaze shifted to the scroll in his hand.
"Could it be… related to this?"
He opened it.
"Lightning Release: Thunder Sphere Technique? Ninjutsu? Chakra?"
"A prank… or something else?"
Kokushibo frowned.
He could understand most of its contents—it described a technique requiring something called chakra.
After briefly attempting it and failing, he closed the scroll.
"I'll take this back and show it to Muzan-sama."
With that, Kokushibo vanished into the forest in a few swift movements.
…