"Shinobu, continue."
Shinazugawa Sanemi shot Naruto a fierce glare before immediately turning to Kocho Shinobu, his impatience barely contained.
"Explain it properly. What exactly is this Mark? Can it increase our strength? And more importantly—can we awaken it too?"
Kocho Shinobu nodded. She had originally intended to discuss this matter only after all the Pillars had gathered, but given the current situation, it was obvious no one here could wait.
"When I examined Naruto-kun," she began calmly, "I noticed something strange. The patterns on his face didn't resemble scars left by combat. They were closer to an imprint—something engraved rather than wounded."
She continued, "Because of this, I reported the matter to Master Ubuyashiki. After hearing about it, the Master was deeply surprised… and then unusually excited."
Shinobu's expression grew serious.
"He told me that during the Sengoku period, several of the earliest Demon Slayers—those who repeatedly cornered Kibutsuji Muzan—had similar patterns on their bodies. These were known as Marks."
Naruto listened quietly as Shinobu went on.
"However, many of those swordsmen died before their Marks could fully manifest. As a result, numerous theories arose regarding how the Mark was inherited or awakened. Over the centuries, no swordsman capable of manifesting a Mark appeared again."
She paused briefly.
"And due to the Demon Slayer Corps suffering repeated near-extinction events throughout history, most records related to the Mark were lost."
"Fortunately," Shinobu said, "the Ubuyashiki family preserved the diary of one Marked swordsman. While the records are incomplete, one thing is certain—awakening a Mark dramatically increases the power of a swordsman who uses Breathing Techniques."
"So that's it…" Shinazugawa muttered, staring at the patterns on Naruto's face.
"You're saying Naruto defeated an Upper Moon because he awakened a Mark?"
His eyes burned with urgency.
"Then tell me—how do we awaken it?"
The other Pillars fixed their gazes on Shinobu, anticipation thick in the air.
"I'm afraid…" Shinobu shook her head gently, "…there is no clear method recorded."
She hesitated, then continued carefully.
"And according to the same records—every swordsman who awakened a Mark died before the age of twenty-five."
"So what?!"
Shinazugawa exploded, cutting her off without hesitation.
"If it makes me stronger, I don't care if I only live one more day!"
He looked back at Naruto's face with unmistakable frustration.
"The real problem is figuring out how to awaken this damned thing!"
"There may be a clue," Shinobu said after a moment. "When we retrieved Naruto-kun after his battle with Upper Moon Three, his condition was extremely abnormal."
She turned to Naruto.
"Your body temperature had exceeded forty degrees Celsius. And while I was trying to lower it, I noticed your body was undergoing a rapid transformation."
She met Shinazugawa's gaze.
"I believe that state may be one of the necessary conditions for awakening a Mark."
The Pillars froze.
"Above forty degrees?!" Shinazugawa shouted.
All of them turned to Naruto at once, eyes blazing.
Naruto's scalp prickled under the attention.
"…Well," he said awkwardly, thinking hard,
"at first, I couldn't beat him. I almost died several times. My body hurt so much it felt like it was falling apart."
He swallowed.
"Then I felt really hot—like my whole body was burning. After that, my strength suddenly exploded. I beat him… and then I passed out. That's all I remember."
Shinazugawa slammed a fist into his palm.
"That's it! It's body temperature! If we raise our body temperature high enough, we can awaken the Mark!"
"Absolutely not."
Shinobu rejected the idea instantly.
"If it were that simple, the Demon Slayer Corps wouldn't have gone hundreds of years without another Marked swordsman. There must be additional conditions."
She added coldly,
"And sustaining a body temperature above forty degrees Celsius is lethal—even for a Hashira."
"What's there to fear?" Shinazugawa scoffed. "I'll be the first to try."
"No," Shinobu said firmly.
"Naruto-kun maintained that temperature for seven full days, and during that time, he was constantly on the verge of death. We don't know how long such a state must be maintained, or what other factors are involved."
She paused, then revealed something crucial.
"However, there was one particularly important line in the diary."
She quoted it slowly:
'When one manifests the Mark, others nearby shall resonate and follow.'
"The Master interprets this to mean that once a Marked swordsman appears in an era, those around him will inevitably awaken Marks as well—given time."
"That is why the Master called Naruto-kun the 'strong wind' that will push this era forward."
Shinazugawa fell silent, clearly struggling to accept it.
"…Even so," he muttered, "I still want to try."
He looked at Shinobu seriously.
"Is there really no safe way to raise my body temperature?"
Shinobu shook her head without hesitation.
"No. And until we understand all the conditions required to awaken a Mark, forcing it would be suicide."
Shinazugawa clicked his tongue in frustration.
"Damn it…"
Suddenly, he grabbed Naruto by the collar and roughly ruffled his hair.
"You brat! Think harder! There has to be something else you're not telling me!"
"I—"
Naruto was about to answer when a loud voice rang out.
"Wait!"
Kyojuro Rengoku stepped forward, staring at the nichirin blade in Naruto's hands with wide eyes.
"Naruto—what's going on with that sword?!"