The moment the two injected chakra into their kunai, Minato Namikaze received a notification that the mark had been triggered. He was currently serving as a close attendant to Fumori Masaki, specifically to be able to instantly transport Fumori Masaki to his destination.
Minato Namikaze had just turned around and hadn't yet spoken when Fumori Masaki already sensed some movement and walked out of the house. He looked at Minato Namikaze, and with just a glance, he immediately understood what the other person meant.
Fumori Masaki took a deep breath, and the chakra within him began to stir. His own chakra nature and the chakra nature condensed from tailed beast chakra fused, creating a powerful new force.
Minato Namikaze saw a strong light emanating from his teacher, carrying heat like flames. He also had a talent for perception, so he naturally understood the immense power contained within. He felt that this power could even evaporate him completely.
However, due to Fumori Masaki's control over his own power, although he could feel the vastness of this power, it was kept within a perfectly appropriate range. Minato Namikaze's body only felt a warmth like sunlight.
"I'm leaving first. Please call Kagami over later," Fumori Masaki said.
"Yes," Minato Namikaze nodded, throwing three Flying Thunder God kunai that pierced the ground around Fumori Masaki. Since Fumori Masaki had instructed him not to follow, to transport Fumori Masaki alone, he couldn't take him personally but had to rely on the kunai's marks for the jump.
Fumori Masaki instantly vanished from his spot. Minato Namikaze slowly lowered his hands, which had been forming a hand sign, and said to the now empty kunai array, "I wish you good fortune in battle."
At the same time, Uchiha Koku also felt a bad premonition and intended to strike again. The chakra giant hand of his Susanoo forcefully grabbed towards that direction, and countless twisted shadows emerged, far surpassing the previous number. Just then, a person suddenly appeared in the sky near Yūki Fujimura and Ken Uchiha. This person emitted a radiant light, as if their entire being was made of light.
It wasn't the first time Uchiha Koku had seen such an appearance. He immediately blanched and then, without hesitation, increased the power of his Susanoo. But in the next moment, a tremendous force erupted from the light-filled person.
Uchiha Koku only saw the arms of his Susanoo shattering layer by layer, and even those twisted shadows seemed to be crushed by something, disappearing without a trace. He himself also felt immense pressure, and the body of his Susanoo seemed to groan under the strain, as if it could collapse at any moment.
Uchiha Koku's eyes widened, and the Susanoo's form was further strengthened.
A layer of heavy armor covered its surface, finally blocking the invisible immense force, but he himself was pushed back a certain distance.
—What was that? Wind Release?
—Or was it natural energy?
All sorts of conjectures arose in Uchiha Koku's mind. The attack unleashed by the opponent was too unexpected, almost like pressure from the heavens and earth.
If Uchiha Koku had cultivated the Rinnegan, he might have found the form of this technique very similar to a certain Rinnegan ability, called Shinra Tensei, which controls a force called repulsion, like the laws of the world, and its counterpart, Bansho Ten'in, which controls a force called attraction.
Of course, Fumori Masaki, who unleashed this technique, did not possess the Rinnegan, so he naturally wouldn't use such an ability. The principle of his technique was based on the natural energy that constantly permeated the world, transformed by the nature of Wind Release, surging towards Uchiha Koku like a tsunami.
In its manifestation, it was very similar to the repulsive suppression of Shinra Tensei, but ultimately it was different, although Fumori Masaki felt that perhaps there were some commonalities in certain aspects.
Unlike Shinra Tensei, which releases repulsion in all directions, Yūki Fujimura and Ken Uchiha, who were behind, were not affected by this powerful force, only feeling a gentle breeze on their faces.
Although Fumori Masaki couldn't perform precise pinpoint calculations during the high-speed teleportation of the Flying Thunder God like Minato Namikaze—which meant he couldn't become a Flying Thunder God ninja—his reaction speed was impeccable. The moment he appeared, he understood the current situation and immediately unleashed his technique.
It was only after Fumori Masaki entered this new state that he gained such control. He didn't have a clear name for this technique, but because it looked very similar to Shinra Tensei, he temporarily called it "Pseudo-Shinra Tensei."
Uchiha Koku stared intently at the radiant figure, his alien-like face gradually twisting. He gritted his teeth and said, "Fumori Masaki—!"
Fumori Masaki also looked at Uchiha Koku, but he spoke to the two behind him, "Are you two alright?"
"Yes! Hokage-sama." The two were not unfamiliar with Fumori Masaki's current appearance, having witnessed it during the breakout in the capital. They immediately responded, relieved. The Flying Thunder God summon was successful, and with the Hokage's arrival, this matter might be over.
"You two should go quickly. I'll handle this here," Fumori Masaki said. His perception was extremely keen now, and he could confirm that Uchiha Koku was the real one, and there were no other presences nearby. Now, he could even sense Black Zetsu's stealth technique, so he told the two to evacuate immediately. Even if Uchiha Koku had arranged for other people, they might not be able to defeat the two.
The two agreed. Before leaving, Ken Uchiha recalled Amaterasu, using Transfer Sealing to seal it back into his Mangekyo Sharingan, to prevent it from causing trouble for the Hokage's battle.
"I know you've been watching me constantly. Coming out this time was a bit risky, but I had no choice but to appear, otherwise the success rate in the future would become even lower," Uchiha Koku said in a deep voice. "It seems my luck isn't very good; I couldn't take them down in one go."
"Because they are also very capable, and no longer someone you can simply manipulate. Although you possess the same Mangekyo Sharingan as Madara Uchiha, you are not him after all. If it were him, I might not have been summoned here," Fumori Masaki said calmly.
No matter how powerful a Sharingan is, one fact remains unchangeable: the Sharingan is merely a weapon, a weapon that can amplify combat power. The user's skill determines how much power can be unleashed. Madara Uchiha has nearly ten years of experience in this. Even if Uchiha Koku has something special about him, can he catch up to Madara Uchiha's ten years of experience?
"Do you think you've already secured victory?" Uchiha Koku raised an eyebrow slightly. "Although I wanted to take the targets directly, I also considered the possibility of being obstructed by an unexpected event. Now that you've appeared, it's still within my expectations—though not what I wanted to see. But since it's come to this, let's have a good fight here!"
Uchiha Koku understood that since Fumori Masaki had appeared here, he couldn't leave safely. Fumori Masaki's Sage Mode had reached a very high level, and his Mangekyo Sharingan could clearly see the vast, endless chakra contained within his body, and it was unusually stable. Fumori Masaki appeared to be radiating light and heat, as if energy was constantly dissipating, but in reality, all that dissipating energy was contained within his body's surface, ready to be released in one go when necessary.
"The unresolved outcome in the capital, let's end it here," Fumori Masaki nodded slightly.
The battle was imminent. Fumori Masaki instantly appeared before Uchiha Koku, blending into the natural environment without a ripple. Fortunately, Susanoo could be quickly summoned with a thought, and deep purple chakra blocked Fumori Masaki like a dam.
Fumori Masaki's figure abruptly stopped, then surged upwards, becoming a streak of light that swept across Susanoo's surface. Numerous linear marks immediately appeared on Susanoo's body, all places where Fumori Masaki had rapidly slashed with Wind Release. Uchiha Koku quickly turned his head and saw a gap in the area not covered by heavy armor.
Susanoo's heavy armor did not completely cover its body. Although Susanoo itself possessed extremely high defensive capabilities, the areas not protected by heavy armor would naturally have lower defense.
In the original story, during the battle between Danzo Shimura and Sasuke Uchiha, Danzo Shimura discovered a weakness in Sasuke Uchiha's Susanoo's back. He then combined with the powerful suction of his summoned beast, Baku, to amplify his Wind Release, tearing open Susanoo's back in one go and allowing him to rush inside.
If Sasuke Uchiha hadn't immediately used Fire Release to deal with Baku's suction, allowing Susanoo to move again, he would have been in great danger at that moment.
Fumori Masaki's mastery of Wind Release was even superior to Danzo Shimura's, and his current state surpassed ordinary Sage Mode. The Wind Release he unleashed was even more extraordinary in power. In an instant, he found Susanoo's weak point, then used Wind Scythe to pierce it, creating an opening, and rushed inside.
Uchiha Koku's face twitched slightly. He couldn't force himself away in time; Fumori Masaki's speed was far superior to his. His body was instantly pierced and split into two.
But as Fumori Masaki expected, the two halves of Uchiha Koku's body vanished like fragments, as if the Uchiha Koku he had just defeated was merely an illusion.
It looked very similar to Izanagi, which turns unfavorable reality into an illusion, but Fumori Masaki finally saw its essence at this moment. He raised his sword and swung it. The sword light instantly enveloped the vicinity, and the scene of shattering mirrors vaguely reappeared.
"I understand now what your Mangekyo Sharingan ability is," Fumori Masaki said, looking at Uchiha Koku, who had appeared on a nearby tree, panting and covered in sweat.
"You figured it out?" Uchiha Koku said.
"Ah, I had a feeling about it back in the capital, and the two slashes just now confirmed it even more," Fumori Masaki said. "As expected of a Mangekyo Sharingan dōjutsu, the speed is incredible. If it were an ordinary Substitution Jutsu, there wouldn't have been enough time to use it."
"A Mangekyo Sharingan dōjutsu can be used with just a thought, unless the Sharingan temporarily disappears, or the speed is so fast that even thought cannot be sent out in time," Uchiha Koku said. From this statement, it could be seen that he admitted Fumori Masaki's previous words were correct.
"Your thoughts can at least keep up with my speed. However, since it's a technique similar to the Substitution Jutsu, there must be something being exchanged," Fumori Masaki said.
This is the basic principle of the Substitution Jutsu. For example, Sasuke Uchiha's Rinnegan ability—Amenotejikara—is similar to an advanced Substitution Jutsu, allowing for exchanges regardless of others' will. Sometimes, it can swap the enemy's position with his own, and can even swap air, thereby achieving an effect similar to space-time movement.
"Can't you tell what I'm using for the exchange?" Uchiha Koku sneered.
"No, I actually figured it out. From the moment I saw through the essence of this technique, I understood why you made those moves."
"What moves?"
"It's about inciting war and indiscriminately attacking others with chakra samurai. What was it all for—you were collecting souls, weren't you?"
"You really did figure it out," Uchiha Koku showed no panic at having his secret exposed. Instead, he laughed heartily, then composed himself and said, "That's right, what my Mangekyo Sharingan exchanges are the souls of others. This is a unique ability of my Mangekyo Sharingan."
"It truly is a wicked path. Those shadows must be the souls you collected, right?"
"That's right," Uchiha Koku admitted openly. "These souls are all under my control. They can be used to attack others, and they can also be used for substitutions. Don't you think this is a very useful dōjutsu? It's simply offense and defense in one."
"I'd like to ask, what happens when these souls disappear after being attacked?"
"What happens? Of course, there's only one possibility." Uchiha Koku didn't say that these souls would eventually go to the Pure Land, but gave an answer that made Fumori Masaki frown: "—They are utterly annihilated!"
"..." A tremendous pressure faintly emanated from Fumori Masaki's body. For Sage Mode, which has extremely strong control, this was a very rare occurrence.
"What's wrong? Are you angry? Then you're welcome to come and kill me. However, I can tell you, no matter what methods you use, I can evade them until all the souls are exhausted. And when you can truly kill me, the souls will already be completely exhausted. All those people will be utterly annihilated, never to be reincarnated!"
Uchiha Koku knew that Fumori Masaki was a moral person. He could understand what kind of blow it would be for such a person if someone's soul could never be reincarnated. But he was willing to see this scene. Even if he might truly lose to Fumori Masaki, he would still use this method to strike at him.
"Uchiha Koku, you truly deserve to die a thousand deaths, but if you think this can tie my hands, you are gravely mistaken!" Fumori Masaki took a deep breath, with a hint of anger: "I will offer your soul as a sacrifice to those who have already been utterly annihilated."