After completing the experiment, Uchiha Shinji and Yakumo left the laboratory together, heading toward the Shinobi Academy.
"I never imagined those monsters' flesh contained such terrifying power. Even the most potent poisons we've collected can't completely destroy their cellular tissue…" Yakumo remarked as they walked, unable to hold back her awe.
For the past few days, Tsunade's experiments had focused on countering the demons' flesh regeneration.
After all, during the Land of Grass war, 'Upper Moon' had been defeated, but high-ranking members like 'Upper Moon One,' 'Upper Moon Two,' 'Upper Moon Three,' and the terrifyingly powerful mysterious figure had only vanished, not been confirmed dead. The village had to prepare for the possibility of 'Upper Moon' making a comeback.
Thus, finding a way to suppress the demons' flesh regeneration became the top priority for Tsunade's research team.
"Indeed," Shinji sighed softly.
Honestly, the raw data had shocked him too, given the demons' flesh regeneration capabilities.
Even the First Hokage, known for the most formidable regeneration in the shinobi world, only theoretically possessed limb-regeneration potential. The hidden cost of such rapid regeneration was evident in the First's early death.
But demons were different.
Leaving aside high-tier demons like 'Upper Moon,' even ordinary demons could effortlessly regenerate limbs.
Moreover, demons had astonishingly long lifespans.
As long as they consumed fresh flesh, they could sustain their lives almost indefinitely.
Shinji recalled that in the original Demon Slayer timeline, Muzan Kibutsuji, endowed with the Demon King's power, aged nearly nine thousand years after being dosed with an aging drug and still didn't die immediately.
Nine thousand years!
Setting aside everything else, that lifespan alone could outstrip the 'Sage of the Six Paths.' Perhaps only Kaguya Otsutsuki, the 'Goddess of the Rabbit' sealed on the moon, could compare in the shinobi world.
So, in all honesty, the most precious asset of the Demon Slayer world wasn't the swordsmen's Breathing Techniques or their special abilities that unlocked human potential and the selfless state.
The greatest treasure of the Demon Slayer world was its near-invincible flesh-and-blood power!
Soon, the two arrived at the Shinobi Academy and returned to their respective classes.
During class, Shinji let his mind wander, mentally reviewing the suppression protocols Tsunade had specially devised for the demons' flesh-and-blood power.
It was no secret that demons feared sunlight.
With this direction in mind, Tsunade had rapidly enhanced the potency of her poisons. Shinji believed that given a bit more time, she would surely develop an agent to counter the demons.
His secret laboratory, meanwhile, was equipped to replicate any drug. Once Tsunade made a breakthrough, he could immediately reproduce it.
That Evening, Outside Hidden Leaf Village.
Swish.
A figure landed in the forest, glancing around cautiously.
Karin emerged from behind a large tree, calling out, "I'm here!"
Seeing Karin, the figure hurried over, lowering their voice and bowing. "Leader!"
Karin said, "Ryuzetsu, don't worry. There's no one nearby."
The person sneaking out to meet Karin was none other than Ryuzetsu's sister, Ryuzetsu.
For such matters, Ryuzetsu trusted no one else.
Ryuzetsu had learned from her brother that Karin was the true leader of the village and possessed strength surpassing a Jonin. Hearing Karin confirm the area was clear, she relaxed, steadied herself, and reported, "Leader, the Anbu received word that the five great shinobi villages are secretly collecting various poisons and toxins, purpose unknown!"
Karin nodded slightly, signaling Ryuzetsu to continue.
Ryuzetsu added, "Elder Mizawa, who was investigating the 'Box of Ultimate Bliss,' has been missing for days. Brother fears he may have met with an accident!"
Karin deliberately paused, then said, "Temporarily suspend the investigation into the 'Box of Ultimate Bliss.'"
"Yes!"
Ryuzetsu nodded.
As a member of the 'Grass Flower' faction, she had no fondness for the 'Box of Ultimate Bliss.' To her, it only brought calamity to the village.
After sending Ryuzetsu off, Karin hurried to the secret laboratory, relaying the intelligence gathered by Hidden Grass Village to Shinji.
"Collecting poisons and toxins?"
Shinji was momentarily stunned, then gave a wry smile.
Clearly, Hidden Leaf wasn't the only village targeting the demons. The other four great shinobi villages were likely conducting their own covert research on them. The mysterious figure had released too many demons during the Land of Grass war, so it was no surprise that other villages had captured one or two.
The other villages' current research focus, like Tsunade's, was likely on countering the demons' rapid regeneration, explaining their large-scale collection of poisons and toxins.
"Now the entire shinobi world is racing to uncover the demons' weaknesses. It won't be long before results emerge!"
With this in mind, Shinji turned to Karin and instructed, "Go back and prepare. Chakra will be transferred soon."
"Understood!"
Karin nodded and left.
After calibrating the instruments in the laboratory, Shinji departed, quietly returning to Hidden Leaf Village and his apartment.
After a quick wash, he sat on his bed, activated Jikibi, and contacted Sasuke.
Sasuke, reached by his leader, eagerly asked about his doubts regarding the 'Eternal Mangekyo Sharingan.'
After probing a bit and learning Sasuke had heard about it from Itachi, Shinji marveled at Itachi's meticulousness while replying, "You guessed right. Both 'B' and I possess the Eternal Mangekyo Sharingan!"
"What?!"
Sasuke couldn't hide his shock.
Truthfully, he had been resistant to the idea that something like the Eternal Mangekyo Sharingan existed beyond the Mangekyo Sharingan.
Even with some mental preparation, the confirmation still left him reeling.
Shinji considered for a moment, then said, "Do you know why Itachi spared your life?"
Sasuke asked urgently, "Why?"
Shinji replied slowly, "Because advancing to the Eternal Mangekyo Sharingan requires a pair of Mangekyo Sharingan from a blood relative! And your eyes are what Itachi needs!"
"So that's how it is…"
Sasuke's tone grew icy.
Shinji paid no mind to Sasuke's emotional turmoil and instructed, "Tonight, I'll absorb your chakra. Be ready!"
The Land of Grass war had delayed his 'Rinnegan Plan' for quite some time. With the mysterious figure temporarily repelled, he needed to accelerate the plan, aiming to possess at least one pair of Rinnegan by the time they counterattacked the Demon Slayer world.