"Have you ever thought about this? Since Minato Namikaze could use the Flying Thunder God, why not have disposable operatives deliver countless specially made Flying Thunder God Kunai directly into the enemy's headquarters, then launch a devastating strike against their command system..."
Ever since the unconvinced Hiruko had another friendly discussion with Kato Osamu and became the first person to survive the Triple Soul Sonata, he had never again mentioned test subjects or challenging Kato Osamu.
The words "test subject" had now become something of a taboo for him. Within the illusion, Kato Osamu had conducted fascinating studies on pain using countless methods...
"Or even transport countless Explosive Tags and directly transfer techniques just before they are unleashed. With constant harassment like that, he could win without fighting. The enemy would not even be able to touch the hem of his clothes..."
But Hiruko was unlike his usual self today. Instead of seeming to avoid him, he actually dared to barge straight into his laboratory and talk at length.
"If you do not say anything that interests me today, then you will learn what the highest level of pain truly is..."
Hiruko hesitated only slightly before looking once more at Kato Osamu, who was busy at the experimental table.
A-Three had urged him many times already. For the first time, he felt an inexplicable reluctance to disappoint this Root shinobi, though he wanted even less to see the brat before him.
"Hmph. If you had the chance to spend countless days and nights painstakingly researching a single ninjutsu as I did, then you would understand the enormous secret hidden within it..."
"No wonder... It seems Danzo had long begun researching the Flying Thunder God..."
Kato Osamu stopped what he was doing. As he thought to himself, he merely raised his eyes to glance at Hiruko. A faint, inscrutable smile touched the corner of his lips, making Hiruko feel an inexplicable chill all over his body.
"During the Flying Thunder God's spatial jumps, it merely relies on those special Kunai for positioning and traversal. While within chaotic space, the process of connecting to the coordinates of a special Kunai is simply activating those sealing inscriptions with Chakra to find a fixed direction."
"So... what is wrapped around the handle of those special three-pronged Kunai is actually a sealed strand of Chakra used to activate the Flying Thunder God Runes?"
"Of course..."
"You should know this... Those runes are also a type of Sealing Jutsu... and Sealing Jutsu requires time to activate..."
"Only by following a preset flow of Chakra and sealing a certain amount of Chakra within them can the Flying Thunder God Runes be activated in an instant, achieving nearly instantaneous speed..."
Hiruko glanced at the contemplative Kato Osamu and relaxed his slightly furrowed brow.
"There are two ways to activate the inscriptions. One is through one's own Chakra remaining upon them, and the other is through Chakra injected by someone else..."
"For example, the Flying Thunder God Runes on your arms when you and Minato Namikaze were on the Cloud Shinobi battlefield could be activated through your own Chakra, giving Minato Namikaze clear spatial coordinates..."
"You are telling me this because you want to say that you have already developed a way to counter the Flying Thunder God?"
Kato Osamu's cold gaze swept over Hiruko. Hiruko could not help snorting softly and looked away from Kato Osamu's eyes.
"I have a general direction... but I still do not know whether it will succeed... I may need your cooperation..."
"Speak..."
"A Cursed Seal that can erode Chakra..."
Kato Osamu slightly raised his eyes at Hiruko. The mention of Cursed Seals seemed to have drawn a little more of his attention.
"When the Flying Thunder God connects with its runes, its user's Chakra will inevitably first make contact with the Chakra inside the runes, whether it was sealed there or injected by someone else."
"If some kind of Chakra-eroding Cursed Seal is injected into them when Minato Namikaze connects with the Flying Thunder God Runes, the Cursed Seal entering Minato Namikaze's body along his Chakra could cling to him like a parasite in the bone. He would have no choice but to use even more Chakra to remove it, and depending on the Cursed Seal's effects, there could be even more options..."
"Would Tobirama Senju, the Second Hokage, praised as the Shinobi World's foremost master of forbidden techniques and divine speed, have failed to notice such a flaw in the Flying Thunder God?"
"Hiruko, if you want to die, I can send you on your way early. That way, you will not die even more miserably after going to Root..."
"Tobirama Senju thought of it and provided a corresponding solution. But as far as I know, Minato Namikaze never leaves behind a single Flying Thunder God Kunai after any battle. Even the special Kunai that can be used long-term are only given to those close to him..."
"Even if Root obtains a special Flying Thunder God Kunai, the runes on it will lose their function and it will become an ordinary Kunai..."
Hiruko's utterly certain expression left Kato Osamu temporarily unable to determine whether this method would work, but he vaguely sensed a plan with immense potential.
"You just said that every use of the Flying Thunder God requires first connecting with the runes, then activating them through Chakra..."
"If some method could interfere with that connection..."
Kato Osamu's low voice slowly echoed through the laboratory. Hiruko's eyes grew brighter and brighter. As though he had forgotten the pain Kato Osamu had inflicted upon him, he eagerly took up the thread.
"Then Minato Namikaze would become a blind man who had lost his eyes, eternally exiled within the ultimate darkness of spatial turbulence..."
"Blind... darkness... the Bringer-of-Darkness Technique?"
Suddenly recalling a genjutsu he had mastered long ago, Kato Osamu roughly understood that this certain-kill move against Minato had already begun to take shape...
"You heard nothing about this method of breaking the Flying Thunder God by interfering with Minato Namikaze's connection to the Flying Thunder God Runes. Understood?"
The excited Hiruko was suddenly enveloped by a frigid, sinister Chakra. The heat in his heart seemed to be extinguished in an instant. He turned his head and looked into Kato Osamu's icy eyes, remaining silent.
"I can tell you now that level-twelve pain is like the pain of childbirth..."
"If you want to experience it... I do not mind wasting a little time..."
Hiruko's eyes suddenly constricted. His hands clenched tightly into fists, his Adam's apple bobbing as he looked at Kato Osamu. It was as though he was not looking at a person, but at a monster wearing human skin, one with an indescribable gloom about him.
"I understand..."
A-Three stood quietly at the entrance to the laboratory, seemingly waiting for Hiruko, yet also seemingly just silently guarding the laboratory door.
Anger still lingered in Hiruko's eyes as he emerged from the laboratory, but a large hand gently settled on his shoulder.
"Do you still not understand why the leader of Root did not plant the Cursed Tongue Eradication Seal on you?"
The eyes behind the mask carried a trace of what seemed like faint concern. Hearing A-Three's words, Hiruko's eyes abruptly widened. If he still could not understand after this, Danzo would never have entrusted him with such an important task.
"You mean... Danzo... Damn it!"
"At the very least, he will let you live..."
A-Three glanced toward the tightly shut laboratory door, then seemed to turn back into a statue, without another word.
Hiruko silently stared at the laboratory door. His clenched hands slowly dropped, and he turned to look at A-Three, a complicated glimmer appearing in his eyes.
"I know that you and he may belong to the same organization that betrayed Danzo. Perhaps everything you have done was merely to help him..."
"But... I will trust you this once..."
Seeing that A-Three gave no response whatsoever, Hiruko silently sighed. His figure quietly vanished into the darkness.
In a pitch-black corner stood several instruments Kato Osamu had discarded from the laboratory. Hiruko worked there in silence.
Before you continue