In my previous life, Izuna had been a terrible student, but he'd always been interested in history.
History was full of examples of alliances being broken apart through schemes of discord.
During the Sengoku period, Qin had used such a scheme to break the alliance of the six other states. In the Three Kingdoms period, Cao Cao had done the same to the alliance between Ma Chao and Han Sui, securing victory.
According to Sora Uchiha, the Fūma Clan, the Saitō Clan, and others had clashed repeatedly in the past over food resources.
The other Four Clans had only banded together for the time being, spurred on by Masashige Hagoromo and coveting Uchiha's fertile lands.
In this world, this book was first published on .
Izuna was confident he'd find a chance to break up their alliance.
For now, the Ino-Shika-Cho Three Clans had no plans to march out from their clan territories, so he could relax—at least temporarily.
However, less than three weeks after the first battle, the Five Allied Clans Army had grown bold again.
They launched a series of attacks, but Uchiha drove them back every time.
Although Izuna had killed Kōkawa Yokōichi, the Onigawa Clan hadn't withdrawn from the alliance. Instead, they'd chosen Yokōichi's younger brother, Kenji Kōkawa, to take over as their new clan leader.
In today's battle, even Masashige Hagoromo, the alliance leader, had joined the fight personally. He'd only entered the fray in the latter half of the battle, but there was no doubt about it—he was at Kage Level.
Izuna, who hadn't used the Mangekyo, had failed to kill him.
Just before today's battle ended, during their final exchange of blows—
Izuna had clearly heard the old man Masashige Hagoromo tease him, "It seems you can't use that power repeatedly."
The weakness of the Mangekyo had been exposed. Izuna had expected it, but that didn't stop him from feeling annoyed.
"The enemy will attack more frequently from now on. Tell everyone to be on their guard."
After returning to camp to rest, Izuna gave Sora Uchiha his orders.
"Yes."
Sora Uchiha nodded, then left, his body covered in blood.
Izuna opened the system's skill tree:
[Skill Points available: 86]
That was enough!
The technique Izuna had been waiting for all this time was the Flying Thunder God Technique.
With a thought, the translucent text on the screen quickly changed. The "86" beside Skill Points dropped to "6" at an astonishing rate.
At the same time, the first row of the Flying Thunder God section, which had been dim, lit up.
[Flying Thunder God Technique (B-rank): Learned] → [Flying Thunder God Second Stage (A-rank): Locked, Skill Points required: 40] → [Flying Thunder God Third Stage (S-rank): Locked, Skill Points required: ??]
The A-rank Flying Thunder God only cost 40 points?
Izuna paused, then quickly understood. To learn the Flying Thunder God Second Stage, he needed not only Skill Points but also the basic Flying Thunder God Technique.
In other words, it should cost 120 points altogether.
Knock, knock—
Soon after he mastered the Flying Thunder God, a knock came from outside.
"Come in."
Creak—
The old wooden door opened with a sound that made his teeth ache.
Ise Uchiha came in carrying a small wooden box. He said quietly, "Vice Clan Leader, the items you asked for."
"Thanks for the effort. Put them down, then go get some rest."
With his back to him, Izuna fiddled with the Flying Thunder God Kunai he'd just taken from the system inventory.
"Vice Clan Leader, these things—"
Ise Uchiha hadn't finished speaking when he suddenly felt the temperature in the room drop. He hastily stammered, "I-I'll take my leave! I'll take my leave!"
Thud!
The wooden door shut again.
Izuna opened the box. Inside was an orange spiral mask with a single eyehole, along with a long, pure-black robe.
After putting them on, Izuna looked at his reflection in the window.
Yes, that was exactly how Obito Uchiha had dressed when he'd gone by the name "Tobi" in the future.
Poof!
Izuna formed a cross-shaped hand seal, and amid a cloud of smoke, another Izuna appeared in the room.
Shadow Clone Technique!
He probably wouldn't need the clone, but it was better to have one around just in case.
Whoosh!
The next second, Izuna opened the window and hurled the Flying Thunder God Kunai high into the air ahead of him. It flew at least half a mile.
He vanished from where he stood, then reappeared almost at once, high in the air, more than a hundred meters above where the Flying Thunder God Kunai had landed.
Facing the strong wind from above, Izuna grinned with excitement. He snatched the kunai out of the air and threw it forward again.
Vanish, reappear, vanish, reappear!
In just a few seconds, he'd left the Uchiha camp far behind.
Even a shinobi of Jōnin rank would need at least three days to travel from Uchiha's Northwest Stone City.
With the Flying Thunder God Technique, Izuna arrived by dusk the next day.
From the cliff, he could see the flags hanging at the edge of the canyon. Each bore two different clan crests, one on either side.
The Sarutobi Clan and the Shimura Clan!
The reason their crests appeared on the same flag was simple: like the Ino-Shika-Cho Three Clans, their families were allied.
Their alliance had a long and sturdy history. They even placed their crests on the same flag to show how united the two clans were.
Together, their strength could rival the Hyuga Clan, second only to the Uchiha and Senju in the Sengoku period.
Or perhaps even surpass them.
"So Hiruzen Sarutobi and Shimura Danzō's bond had been forged as far back as the Sengoku period?"
Izuna, wearing Obito's Spiral Mask, couldn't help but scoff inwardly. He tossed the Flying Thunder God Kunai into the air and vanished.
At that moment, in the territory of the Sarutobi-Shimura Alliance,
Furukawa Sarutobi and Keizou Shimura, the leaders of their respective clans, sat facing each other over dinner.
"Furukawa, with the Hagoromo Clan leading the Five Clans in their attack on Uchiha's northwest border, and Senju in the east liable to attack at any moment, shouldn't our two clans take this opportunity to—"
Shimura Keizou filled his old friend's cup. His eyes gleamed.
His meaning was clear: they should use this chance to grab a share for themselves!
Yet perhaps it was fate. Furukawa Sarutobi and Keizou Shimura, the grandfathers of Hiruzen Sarutobi and Shimura Danzō, had personalities much like their grandsons.
Though they belonged to the same alliance, Furukawa Sarutobi was cautious. He took a neutral stance toward both Uchiha and Senju and didn't want to offend either.
Keizou Shimura, on the other hand, was a hardliner. He'd always wanted Sarutobi and Shimura to replace Senju and Uchiha as the two strongest clans of the Sengoku period.
"Don't underestimate Uchiha, Keizou."
Furukawa Sarutobi took a sip of wine and said, "It's still uncertain whether Senju and Uchiha will fight. They signed a Truce Agreement less than half a year ago..."
Keizou Shimura snorted. "That's nothing but a piece of paper. How could Senju, Uchiha's sworn enemy, pass up such a once-in-a-lifetime opportunity?"
Boom!
The instant Keizou Shimura finished speaking, a loud crash came from the roof.
As a wooden beam splintered and collapsed, a kunai pierced the center of the tatami in the main hall.
At the same instant the kunai hit the floor, a shadow appeared.
"Who's there?!"
More than twenty shinobi from the Sarutobi and Shimura Clans guarding the hall rushed inside.
Furukawa Sarutobi and Keizou Shimura instantly sprang into fighting stances.
"My name... is Kite."
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