Naruto: The Sage’s Brother

"The tale of the shinobi… nothing more than a grand illusion orchestrated by Black Zetsu—a shadow created by Kaguya, with the sole purpose to unseal his creator, Otsutsuki Kaguya. She was sealed not by two sons, as the world believes, but by three…"

The old man's voice was low and gravelly, carried by the crackling firelight in the dead of a moonless night. His face, hidden behind a tattered veil, only made the weight of his words more chilling.

"Three?" a young voice interrupted, laced with disbelief. "I thought Kaguya only had two sons—Hagoromo and Hamura?"

The old man paused. His breath seemed to catch, as though uttering the name would summon the wrath of the heavens. Finally, he whispered:

"The third son's name was… Otsutsuki Tenshin. A name that the Sage of Six Paths erased from the annals of history."

…..

The earth trembled under the starry sky. A meteor descended, tearing through the heavens before slamming into a mountain. The impact left a massive crater, but at its center, there was no rubble—only a tree, its roots sprawling outward as though they sought to devour the earth itself.

Several Millennia later

In the military encampment of the Land of Sou, soldiers watched in awe as a streak of light fell from the sky, illuminating the forest below.

"Is that a star?" one soldier asked, his voice barely above a whisper.

"How can it be a star? It's moving," another replied, unable to tear his eyes away from the glowing projectile.

"Lord Tenji, what shall we do about it?" The advisor's voice broke the spell as he turned to a young man with black hair and sharp brown eyes.

Tenji's gaze was steady. "Follow it."

"Hai!"

A group of five soldiers quickly gathered and marched toward the forest. When they reached the clearing where the light had vanished, they stopped dead in their tracks.

Standing before them was no treasure, but a woman.

She was otherworldly. Her white robes seemed untouched by the grime of the forest floor. Her long, silvery hair shimmered faintly in the dim light, and her pale eyes carried a cold, distant authority.

"A woman?" one soldier stammered, gripping his sword tightly. "Hey! You—where's the star that fell here? Speak!"

The woman turned her gaze toward him. Her silence was deafening, her pale eyes piercing.

Another soldier pulled him back. "Stop, Kenji. Look around—there's no sign of impact. It's her. She is the star."

The soldiers exchanged wary glances before their leader spoke. "Let's take her to Lord Tenji. He'll decide what to do."

Although they were trained to apprehend strangers, none dared touch her. Something deep within their instincts warned against it.

By the time they returned, the sun had risen.

"A woman from heaven?" Lord Tenji's brow furrowed as he observed the ethereal figure before him.

"What's your name?" he asked.

The woman's gaze remained fixed on him, silent as the grave.

"Answer him! The man before you is the king of the Land of Sou—Lord Tenji!" Kenji barked, stepping closer.

"She might be a spy from the Land of Ka," Kenji continued, his voice laced with suspicion. "We should interrogate her—find out her purpose here."

"Hai!" Two soldiers stepped forward to seize her.

Before they could touch her, all three collapsed to the ground, unconscious.

The woman stood gracefully and approached the throne. Her voice, when she finally spoke, was soft but carried an undeniable authority.

"I am Otsutsuki Kaguya. I am the one who protects the Divine Tree."

A year later

After Kaguya had cast the Infinite Tsukuyomi upon the war-stricken world, she bore three sons.

"Kaguya-sama, they are three boys," the servant announced, presenting each child to her mistress.

Kaguya cradled her first son, his brown hair soft beneath her fingertips. "Hagoromo," she murmured, her voice surprisingly gentle. She placed him in a servant's arms and turned to the second child. His hair was white as hers, his small horns glinting faintly in the light of the Divine Tree. "Hamura," she said, a flicker of pride in her voice.

Then she turned to the third child. Her breath hitched.

He was different. His hair was dark, like the void between stars, and his eyes—impossibly blue, as though they drank in the heavens themselves. He bore horns like his brothers, but something about him felt… wrong. Foreign.

She hesitated before speaking. "Tenshin," she said at last, her tone colder, distant.

The servants exchanged wary glances but said nothing as they carried the infants away.

Years passed.

Hagoromo and Hamura spent their days among the villagers, easing their burdens and solving their problems.

Tenshin did not.

During the day, he sat silently behind his mother, watching her as she gazed at the Divine Tree and the endless sky. She never spoke to him first, not once in all the years they sat together.

At night, he vanished. No one knew where he went, but by dawn, he always reappeared, seated in his usual spot as though he had never left.

One day, while Kaguya stared at the sky, Hagoromo and Hamura knelt before her.

"Mother," Hagoromo began, his voice heavy with emotion. "Please… end the ritual of the Divine Tree."

"That is not possible," Kaguya replied flatly.

"But—" Hagoromo's voice wavered.

"I will not tolerate defiance, even if you are my sons" Kaguya interrupted, her gaze moving from Hagoromo to Hamura. Out of the corner of her eye, she saw Tenshin sitting quietly, his polite smile unchanged.

Hagoromo clenched his fists. "Then tell us, Mother—what happens to those who are part of the ritual? Why does no one ever return?"

"This ritual is necessary until the others arrive," Kaguya said dismissively.

"The others?" Hagoromo asked, his voice trembling with uncertainty.

"You do not need to know about them yet," she said, finally meeting his gaze.

Behind her, Tenshin's smile widened ever so slightly. His clear blue eyes gleamed as a thought crossed his mind.

'The time is close. I guess they've met the little toad… and found Haori in the ritual group. I should start preparing myself.'

Kaguya rose to leave. "Hagoromo, Hamura, Tenshin—I will be away for a time. Take care of things in my absence."

"Yes," Tenshin said softly.

The moment Kaguya departed, Tenshin vanished. He reappeared in a distant cemetery, crouching as he unearthed a small, cube-like object buried beneath the soil.

The cube pulsed faintly as he touched it, only to grow dull moments later. A faint smile crept across Tenshin's face, before twisting into something far darker.

"If everything goes according to plan, I can devour Mother and both my brothers at the same time," he muttered, licking his lips in anticipation.

A/N

This is my first time writing a fanfic, I am open to all criticism to help improve the story.

Since I made no change in Kaguya's story from the anime, I didn't want to rewrite it.