Rinnegan

At the end of Kirigakure Year 27, having finished everything he needed to do in the small town, Seiji prepared to leave.

After storing the various necessities he had gradually purchased in town inside his Storage Scroll, Seiji set off on his journey to Kirigakure.

Land of Frost, Mountain Graveyard. Deep underground lay a vast cavern, where an old man sat alone in withered silence.

His hair stood out in spiky clumps like a hedgehog's quills. The once-flowing long hair had turned dry and pale, while the wrinkles on his face, bloodless cheeks, and clouded eyes all foretold that the old man's life was nearing its end.

The old man was none other than Madara Uchiha, the Shinobi World Asura of old.

In the battle at the Valley of the End, Madara Uchiha had been defeated and killed by Hashirama Senju. But he had correctly anticipated Tobirama Senju's deep-seated malice toward the Uchiha Clan. As a research fanatic, Tobirama would never destroy the corpse of the strongest Uchiha, wanting to uncover the secrets of the Sharingan. Thus, before the battle, Madara had used a Transcription Seal to place the Uchiha Clan's life-for-life forbidden technique, Izanagi, in his right eye. After the battle, just as expected, Tobirama secretly hid Madara Uchiha's corpse in Konoha's back mountains, intending to study the secrets of the Sharingan.

In the end, at the cost of his right Eternal Mangekyo Sharingan losing its light, Madara rewrote reality and returned to life. He then disguised a Shadow Clone as his corpse and silently left Konoha.

After his resurrection, Madara Uchiha began striving to realize his ideals.

During his previous battle with Hashirama Senju, Madara had bitten off a piece of Hashirama's flesh. After reviving, he spat it out and transplanted it into his wound, successfully acquiring Hashirama Cells. As the degree of cellular fusion gradually deepened, Hashirama Senju's face appeared on Madara's left chest. Madara Uchiha, who had failed to compete with Mito Uzumaki, ended up being together with his best friend Hashirama Senju forever in another way.

"The mutually exclusive two forces unite as one, giving birth to all things." Madara Uchiha understood the inscription left on the Stone Tablet by the so-called Sage of Six Paths to mean that the power of Hashirama Senju's Wood Release and the power of Madara Uchiha's Eternal Mangekyo Sharingan could fuse together to obtain the power of all things.

Yet after transplanting Hashirama Cells, although Madara could feel his strength slowly increasing and even later mastered Wood Release, something no other member of the Senju Clan had ever been able to master, the anticipated power of all things never emerged.

Time passed. Now over sixty, Madara Uchiha gradually began to feel his strength failing him. The many hidden injuries accumulated from his frequent battles in his youth slowly began affecting his body, and his power continuously declined. Left with no other choice, in the final years of his life, Madara returned to the underground base beneath Mountain Graveyard and quietly awaited the call of the Pure Land.

In his mind, Madara Uchiha's magnificent life flashed past like a film. Every detail of his love-hate relationship with Hashirama Senju flickered by scene after scene. At seventy-one years old, Madara knew that his end had come.

Just then, the Hashirama Cells implanted within Madara finally completed their fusion with his own cells at the genetic level. After a thousand years, the Chakra of Indra and Asura perfectly intertwined, drawing forth a thread of Chakra bearing the traits of the Six Paths. The moment this Chakra appeared, its total amount rapidly increased. At the same time, it began circulating swiftly through Madara's body of its own accord, before finally surging entirely toward the meridians around his eyes.

Madara's eyes widened. His right eye was grayish white, but the Sharingan in his left eye emerged automatically. Three black tomoe began spinning rapidly, then connected into one and transformed on their own into an Eternal Mangekyo Sharingan. The Sharingan spun faster and faster as the red gradually faded, a trace of purple emerging before rapidly spreading. Ripples appeared across his eyeball—Madara's Rinnegan had awakened!

"Hahahahahaha!" His aged yet unrestrained laughter echoed throughout the entire cavern.

Madara Uchiha, whose natural lifespan was nearly at its end, had finally awakened the Rinnegan at the last moment of his life.

"Summoning Technique!" As if by instinct, Madara brought his hands together, then slammed his right hand forcefully toward the ground before him. An immense amount of Chakra burst forth.

Bang! Thick white smoke filled the entire cavern. When it dispersed, a gigantic humanoid monster with nine eyes and a color like dead wood appeared behind Madara. Ten pillar-like protrusions rose from its back.

"The Demonic Statue of the Outer Path?" The name of the monster behind him naturally surfaced in Madara's mind.

Roar! The statue, newly freed from the moon's seal, let out a furious roar, as though venting its resentment over being sealed away—or perhaps its rage at having been forcibly split apart and stripped of the power of the nine tailed beasts.

Madara formed the "Ram" hand seal and began controlling the statue. Under his command, it gradually ceased its agitation, extending several tube-like appendages and inserting them into Madara's back.

With the life force supplied by the statue, Madara survived. Meanwhile, Black Zetsu, who had lurked nearby for years and had long since fallen into despair, stared at Madara Uchiha's Rinnegan in delighted shock.

Mother, I finally see hope. The Rinnegan has finally appeared! Black Zetsu, who had worked toward this for a thousand years, was overwhelmed with excitement and began secretly planning his next moves.

Madara, having awakened the Rinnegan, also rekindled his hope. A resurrection technique contained within the Rinnegan, known as the Outer Path: Samsara of Heavenly Life Technique, gave him the confidence to continue carrying out what he believed to be his plan for peace.

At the same time Madara Uchiha awakened the Rinnegan, Seiji, who had just begun his journey in the Land of Water, looked toward the northwest in confusion.

"A familiar presence," Seiji murmured.

After thinking carefully for a moment, realization dawned on Seiji's face.

"This presence seems to be the Rinnegan. It feels a little like Hagoromo Otsutsuki's." Having watched from close range both the battle in which the Otsutsuki brothers sealed Kaguya and the battle between Indra and Asura, Isshiki was no stranger to the presences of Hagoromo Otsutsuki and his two sons.

"Looks like that black thing called Black Zetsu was behind this. Then the one who awakened the Rinnegan must be Madara Uchiha!" In an instant, Seiji recalled the consciousness Kaguya had split off before being completely sealed, as well as the scenes he had seen in his previous life of Black Zetsu and Madara Uchiha speaking from the heart.

"This is getting more and more interesting. The windmill of the shinobi world has begun to turn!" Seiji smiled, then set those thoughts aside and continued toward Kirigakure. After all, his top priority now was to digest Isshiki's gift and accelerate his own growth.

Three months later, in the spring of Kirigakure Year 28, Seiji arrived at Kirigakure after sightseeing all along the way.

Nine-year-old Seiji had now reached a height of 150 centimeters. Several months of rest and recuperation had provided his body with ample nourishment, and he no longer looked as frail as before.

Taking out the identification documents that the Exchange Office's subordinates had prepared for him when he passed through the capital of the Land of Water, Seiji casually walked toward Kirigakure's gates.