"During the Warring States period, the God of Shinobi, Senju Hashirama, and Uchiha Madara founded the Hidden Leaf Village in the Land of Fire, the most prosperous region in the shinobi continent. Senju Hashirama became the First Hokage."
...
In a forest outside Kirigakure.
Karatachi Yagura lay leisurely on a sturdy tree branch, propping up a book on his bent knee as he flipped through its pages.
It was a history book on the shinobi world that he had "borrowed" from the Kaguya clan library. As he read, he translated the archaic and complex phrases into simpler language for himself.
"Hashi-ramama~ Mada-la~"
Amused by his own antics, Karatachi Yagura chuckled.
"Seeing how well Konoha's shinobi village system worked, other nations and powerful shinobi followed suit, establishing their own hidden villages. The Land of Lightning, covered in mountains, formed Kumogakure. The Land of Earth, much like Lightning, created Iwagakure. The Land of Wind, with nothing but sand, founded Sunagakure."
"Meanwhile, the Land of Water, isolated on several islands away from the mainland, saw its first Mizukage, Byakuren, establish Kirigakure."
The current year was Konoha Year 42—about one or two years before the Third Shinobi World War.
This history book chronicled the major events of Kirigakure since its founding.
In his past life, Karatachi Yagura had watched Naruto, the long-running shounen anime that defined his childhood. He knew the general world-building, major plotlines, and the Konoha main cast, along with some key supporting characters.
A casual discussion over drinks? Sure, he could talk about it for hours.
But when it came to information about villages outside Konoha? The original series barely provided any details.
And Kirigakure? That was a complete mess—its timeline was chaotic, and its lore was full of plot holes!
Karatachi Yagura scratched his head.
If he didn't read up on this world, how could he possibly make sense of his situation?
"Kirigakure has long enforced a policy of isolation and the infamous Blood Mist doctrine."
As the name suggests, the isolation policy strictly prohibited outsiders from entering and Kirigakure's shinobi from leaving.
The Blood Mist doctrine, however, was far more encompassing—it dictated every aspect of the village's operations. A prime example was the graduation exam of the shinobi academy: to pass, students had to kill their own comrades.
This policy left an indelible scar on Kirigakure.
At first, Karatachi Yagura, like most people, assumed that the Blood Mist doctrine was something Uchiha Obito had implemented by controlling the "Fourth Mizukage Yagura" with genjutsu.
But why would Obito do that? What grudge did he have against Kirigakure?
Oh, right. A very big one.
During the Third Shinobi World War, Kirigakure's shinobi sealed the Three-Tails inside Nohara Rin. Their plan? Once Rin returned to Konoha, the Three-Tails would rampage and destroy the village, securing victory for Kirigakure.
Nice idea, but reality was harsh.
To protect Konoha from the threat inside her, Rin chose to end her own life, throwing herself into Kakashi Hatake's Chidori.
A Jinchūriki's death meant the Tailed Beast inside would vanish. Just like that, Kirigakure's Three-Tails scheme crumbled.
But the real tragedy was yet to come.
Orchestrated by Madara Uchiha and Black Zetsu, Uchiha Obito personally witnessed Rin's death, which pushed him into complete darkness.
From there, Obito—once a mere Konoha Chūnin—embarked on a path of devastation: corrupting Nagato, using genjutsu to manipulate the Mizukage, launching the Nine-Tails attack on Konoha, and even initiating the Fourth Shinobi World War.
"Sigh..."
Thinking about the absurdity of it all, Karatachi Yagura let out a deep sigh, feeling the weight of impending doom.
Because the person he had transmigrated into wasn't just some random background character—
He was that unfortunate guy whom Obito had mind-controlled!
Karatachi Yagura cleared his throat.
"Ahem. Allow me to formally introduce myself! Standing before you is none other than the future Jinchūriki of the Three-Tails, the Fourth Mizukage, Yagura! One of the few in history capable of fully controlling a Tailed Beast!"
…In the future.
Right now, Karatachi Yagura was neither a Jinchūriki nor a Mizukage. He wasn't even a shinobi yet—just a student preparing to enter Kirigakure's shinobi academy.
As far as he knew, that big turtle, the Three-Tails Isobu, was still swimming peacefully in a lake somewhere in the Land of Water.
And the current Mizukage was the Third Mizukage—a character who had only ever been shown in the official timeline and databooks.
No name. No dates of birth or death. No detailed records of his policies.
But one thing was clear—the Blood Mist doctrine had been implemented under his rule.
...
"A few years after Kirigakure was established, with the shinobi world at peace, the First Mizukage, Byakuren, accepted an invitation to the Five Kage Summit hosted by the First Hokage, Senju Hashirama. During the summit, the Third Mizukage served as his bodyguard."
"After Byakuren's death, the designated successor to the title of Second Mizukage was none other than the current Third Mizukage. However, an unexpected challenger emerged—the prodigy of the Hōzuki Clan, Hōzuki Gengetsu. In the selection battle for Mizukage, Gengetsu emerged victorious and assumed the position of the Second Mizukage."
Each village had its own system for selecting its Kage.
For example, in Konoha, the Second Hokage, Senju Tobirama, passed the title to his disciple, Hiruzen Sarutobi. While strength played a major role, connections and lineage were equally important.
In Kirigakure, however, the process was simple and brutal—whoever was the strongest became the Mizukage, no matter their background.
The reason the Third Mizukage had to wait before taking power? He had been beaten down.
At the same time, the backgrounds of the Second and Third Mizukage couldn't have been more different.
The Second Mizukage, Hōzuki Gengetsu, hailed from the prestigious Hōzuki Clan, one of Kirigakure's most powerful and ancient families.
The Third Mizukage, on the other hand, was a commoner. He had risen through the ranks purely on talent and had been handpicked by Byakuren as a bodyguard.
By all accounts, he should have been the Second Mizukage, but fate had other plans—Hōzuki Gengetsu took the title instead.
Just from reading between the lines, Karatachi Yagura could feel the sheer frustration the Third Mizukage must have experienced.
"Gengetsu followed Hashirama's example, adopting Konoha's systems. The Second Hokage established the shinobi academy, so he founded one as well. The Second Hokage created the ANBU and Cryptanalysis Squad, so he established Kirigakure's equivalents."
It wasn't a bad strategy.
Tobirama was a genius. Even if you weren't innovative yourself, copying a top student's homework wasn't a bad move.
"Gengetsu also established the Seven Ninja Swordsmen... enforced an isolation policy to protect village secrets..."
"During the First Shinobi World War, he led an elite force to attack the Land of Earth, perishing alongside the Second Tsuchikage. The Third Mizukage then took over, negotiated peace with the Third Tsuchikage, and withdrew from the war."
Karatachi Yagura turned the page.
His expression darkened as he read the first line of the next entry:
"Upon taking office, the Third Mizukage implemented the Blood Mist doctrine."