In the 46th year of Konoha, beneath the harsh glare of the midday sun deep within the Forest of Death, Akira stirred.
A sharp, searing pain pierced through his chest as he regained consciousness. Gritting his teeth, he muttered to himself, "What the hell...? I was infected with the virus—so why am I still alive? Did they... find a way to neutralize it?"
"You fool, Otoutou."
A cold, familiar voice echoed through the forest. Akira looked up, squinting through the sunlight—and froze.
A man approached, handsome and composed, his expression devoid of warmth. His crimson eyes bled intensity, spinning with the unmistakable pattern of the Mangekyō Sharingan.
"Mangekyō Sharingan... No way. Have I been transported into the Naruto world?" Akira's thoughts spiraled. Despite his life as a doctor, anime and manga—particularly Naruto—had always been his favorite escape. He knew those eyes. Those cursed, beautiful eyes.
The man loomed over him.
"You're still alive despite a pierced heart. Hmph. The medical ninjutsu our mother taught you must've bought you time. But it ends now."
Pain flared as Akira noticed the white kunai embedded in his chest, blood seeping endlessly into the forest floor beneath him. The weapon had been driven in from behind, impaling him against the gnarled trunk of a massive tree.
"He mentioned mother... could he be the brother of this body's original owner?" Suddenly, a torrent of foreign memories flooded his mind.
His name was Uchiha Akira now. The man before him—his own elder brother—was Uchiha Kawa. It was Kawa who had struck him down. And now, Kawa stood ready to finish the job.
"Why...? Why do you want to kill me?" Akira's voice was hoarse. The pain in his eyes grew unbearable, but it was nothing compared to the agony in his chest.
As memories continued to fuse, Akira became more aware. Kawa hadn't possessed the Mangekyō Sharingan in the original memories... It must have awakened recently.
Kawa confirmed his suspicion.
"Akira, do you know the true power of our clan? It's the Mangekyō Sharingan. A cursed gift, awakened through loss and pain. Only a few of us ever gain it."
He stared coldly, windmill-shaped tomoe slowly spinning.
"The Uchiha are said to understand love more than any other clan. But when that love is lost, it curdles into hatred. That hatred generates a unique chakra in our brains. It reacts with our eyes... and awakens the Sharingan."
Kawa paused, as if lost in memory.
"But to awaken the Mangekyō... you must kill the one closest to your heart. That pain... is the price of power."
"So you're killing me just to gain power?" Akira rasped.
"That's one reason. But there's more."
And then Kawa told his story.
In the 40th year of Konoha, the Third Shinobi World War erupted. Akira had just been born. Their father, a reconnaissance specialist, was deployed early and never returned.
Akira never knew him. But Kawa—already a genin—watched their father's funeral with open eyes. That grief awakened his Sharingan.
Swearing vengeance, Kawa joined the war. In two years, he rose to Chūnin. With elite intel gathering skills and his dōjutsu, he became a Tokubetsu Jōnin. His information was critical to Konoha's advantage.
But it wasn't enough. Intelligence meant nothing against overwhelming force. Kawa realized the brutal truth: without power, information was useless.
Their mother, a medic-nin stationed in the Wind Country, became a target. The Sand Village dispatched Ye Cang, the Scorch Release user, to annihilate Konoha's medical base. Kawa had warned them in time, but not even foreknowledge could stop Ye Cang.
When Kawa arrived, all that remained was their mother's desiccated corpse.
"So... you seek vengeance on Ye Cang?" Akira asked.
"Hmph. Ye Cang is nothing. It's not her. It's Sunagakure."
Kawa's voice was hollow.
"No... it's the shinobi system itself. Every village. Every ninja. We're all just pieces on a board. My mother died because she didn't have power."
He looked down at Akira with icy resolve.
"And you will die... because you are weak."
Akira understood then. Kawa was broken. Twisted by grief, hardened by war. He was lost.
Akira's eyes throbbed. More memories flooded in—Uchiha Akira had awakened his Sharingan upon learning of his mother's death. And now, as he faced betrayal by his own brother, his hatred surged.
"These eyes... they're my only chance. I must awaken them fully."
Buying time, Akira whispered, "Where did you learn how to awaken the Mangekyō? The clan doesn't talk about it..."
Kawa smirked. "An old man outside the village. He called himself the 'Uchiha Ghost.'"
Akira's heart skipped. "Uchiha Madara...? No, that's impossible... isn't it?"
"He never gave a name. Doesn't matter. What he said was true. That's enough."
Kawa stepped forward.
"I've said all I needed to. Goodbye, Akira."
His hand reached for the kunai embedded in Akira's chest.
"Damn it... just a little more..." Akira gritted his teeth.
As Kawa's fingers wrapped around the handle, another hand stopped him cold.
Kawa looked down. "Oh? Still resisting?"
What met his eyes sent a chill down his spine.
Akira's eyes had changed.
Twin Mangekyō Sharingan stared back—blood-red wheels with intricate, spinning patterns.
"Yin-Yang Release: Art of Formless Rebirth."
Kawa's expression finally broke.
Utter horror.
Canvas "How is it possible that you can open your eyes?"
Uchiha Kawa never expected that Akira, who was already seriously injured and dying, could also awaken the Mangekyō Sharingan and immediately unleash a pupil technique. He was stunned for a moment, and it was too late to resist.
"Hmph, it's useless. You've been hit by my dōjutsu: Formless Reincarnation. And once ensnared by this technique, there is no escape."
Akira snorted coldly. The moment his Mangekyō awakened, he instinctively grasped all its terrifying secrets.
"I didn't expect it to be such a terrifying technique." Even though it was his own ability, Akira was shaken by the sheer force of the infinite reincarnation process.
A vortex spiraled into existence before Akira's left eye. It immediately began to pull in Kawa's hand that gripped the short blade. As soon as his hand and weapon touched the vortex, they were instantly decomposed and absorbed, disappearing into the swirling void.
Kawa, horrified, released his weapon and tried to leap back. But his body was locked in place by an overwhelming suction force. Even his chakra was being siphoned away.
And as his chakra drained, the suction intensified. It became impossible to mold chakra for any kind of jutsu—every ounce would be devoured and used to further fuel the vortex.
That was the terror of Formless Reincarnation. Aside from the initial chakra required to activate the dōjutsu, the rest was drawn from the target.
If the opponent attempted to resist with ninjutsu, their own chakra would only strengthen the pull of the technique.
This was how Akira, despite being on the verge of death, managed to use this technique against Uchiha Kawa. Any other Mangekyō ability would have been too costly in his condition, especially against another Mangekyō wielder.
But even a powerful jutsu has its flaws. Formless Reincarnation requires physical contact to be activated.
Avoiding the technique would have been simple—stay at a distance or retreat the moment before activation. If Kawa had attacked from afar, Akira would have been finished. But there was no way Kawa could have known the secret of Akira's eyes.
And the story can't just end with the death of its protagonist. Kawa had stepped right into Akira's range, granting him the opening he needed.
Thus, Kawa's fate was sealed. What could have been a swift victory turned into a humiliating defeat, all because of a soul's unexpected arrival and a single misstep.
Unable to resist, Kawa watched himself disappear, piece by piece.
He stared at his vanishing body and knew the end had come. He was filled with reluctant acceptance, but also a strange peace.
Perhaps when his parents died, a part of him had already followed them to the next world. That might be why he harbored such a twisted desire—to kill his own brother in pursuit of power. Now, on death's edge, he finally regretted that decision.
Kawa looked into Akira's eyes and whispered, "Now that I've become your strength, that's enough."
He shut his eyes, a faint smile of release on his face.
But he didn't know that his true brother had already died by his hand. The one who defeated him now was merely a stranger with a borrowed body.
Once Kawa's body was gone, Akira exhaled deeply. In just minutes since his arrival in this world, he'd already experienced more than in the past two decades of his previous life.
Meanwhile, in a shadowy cave far away, a dying Uchiha Madara furrowed his brow. The cursed seal he had implanted in Kawa had vanished without warning.
That curse had been a failsafe, a way to control Kawa should he stray after awakening his Mangekyō.
"Forget it. It was only a backup. Control through force breeds only puppets. What I need is a successor who shares my pain, my will," Madara muttered.
He decided to have Zetsu seek out a more compatible vessel.
Back at the scene, Akira looked down at his chest. To his surprise, the fatal wound had healed. The dagger that had pierced through him had been broken down and absorbed during Formless Reincarnation.
Only torn fabric and a puddle of blood remained as evidence of his brush with death.
"It's all thanks to the power of Formless Reincarnation," Akira sighed with relief.
"If I had awakened a different ability, even if I defeated Kawa, the injury alone would've been fatal."
Indeed, Formless Reincarnation isn't just about absorbing others. Its true strength lies in fusion. Decomposition is merely the first phase.
As a Yin-Yang Release-based Mangekyō ability—akin to the Uchiha clan's forbidden jutsu like Izanagi and Izanami—Formless Reincarnation stems from the Six Paths Sage's creation techniques.
It recognizes that all matter is fundamentally the same.
Formless Reincarnation breaks down the absorbed being into its basic components, discards the unnecessary, and reintegrates the valuable into the caster's body without altering their appearance.
Memories, abilities, chakra, and even physical potential can be gained. And with a transformation jutsu, Akira could perfectly replicate the target's appearance—undetectably.
Akira reached this understanding through the instinctive knowledge granted by the Mangekyō, bolstered by his previous life's deep Naruto lore.
"It's gotta be close to the truth. I studied this stuff religiously—no one understood the Mangekyō better than me," Akira thought proudly.
Thanks to absorbing Kawa's chakra, his injuries were reversed and his body rebuilt stronger than ever.
But like all Mangekyō Sharingan, there's a second ability.
Akira's right eye also carried a power—also called Formless Reincarnation, but with a twist. While the left eye decomposed and fused, the right implanted and recreated.
The right eye allowed Akira to insert his will into any living creature, making them his permanent clone.
These clones would inherit their original memories and skills, but with Akira's soul in control. They could train, grow, and even receive abilities from the original body. Chakra would constantly flow between clone and original, keeping them linked in real time.
But such power comes with limits. Like Shisui's Kotoamatsukami, Akira's eye techniques required a cooldown—fifteen years for each use.
Akira was crushed. He hadn't realized the distinction between his left and right eye, and had unknowingly triggered both simultaneously.
While the left eye successfully targeted Kawa, the right had to find a different target. Its secondary activation condition—physical contact—was triggered via the blood that linked Akira to the tree he collapsed against.
So the tree became the target.
Since it was just a mindless plant, only a tiny amount of chakra was needed. The jutsu succeeded.
Akira now shared consciousness with a big, boring tree.
"Great. A permanent bond with... bark," Akira groaned.
The tree couldn't think, fight, or do anything remotely ninja-like.
"So what's the point? Ugh. What a waste," Akira muttered.
"But hey... it's not a total loss. I wouldn't have found a worthy target anytime soon anyway," he consoled himself.
Besides, thanks to the left eye's ability, Akira had gained Kawa's Mangekyō Sharingan.
And not just any Mangekyō...
The one belonging to Kawa was now his.