Years of Tempering, Each Growing Stronger

From Konoha Year 62 to 65, a full three years passed, yet the winds of the shinobi world never ceased.

On the surface, the five great shinobi villages maintained a fragile peace,

with occasional friction at the borders, but no large-scale war erupted;

yet in the shadows, the Akatsuki Organization's influence quietly spread, the tailed beasts' traces were repeatedly disturbed, and every faction secretly amassed strength, waiting for the moment to reshape the balance of power.

For Naruto, these three years were both atonement and transformation.

In the battle at the Valley of the End, he had given everything he had, yet still failed to keep Sasuke. Watching Sasuke's resolute back vanish at the end of the valley felt like having his heart viciously torn apart.

"I'll become stronger, strong enough to bring Sasuke back!"

Those words became his sole obsession for three years.

Jiraiya looked at the boy covered in wounds but possessing an incomparably determined gaze. In the end, his heart softened. He took Naruto from Konoha and set out on a training journey across the nations.

Over those three years, they traveled through the deep mountains of the Land of Fire, crossed the swamps of the Land of Water, and passed through the deserts of the Land of Wind. Every corner bore Naruto's trace of training.

At Mount Myoboku, Naruto shed the recklessness of a dead last and learned senjutsu from Sage Fukasaku. He endured the agony of senjutsu chakra backlash, repeatedly wandering on the brink of life and death.

There were times when he failed to control senjutsu chakra,

his body covered in frog markings, his consciousness hazy, nearly turning into a frog; there were also times when, under Sage Fukasaku's guidance, he gradually grasped the true essence of senjutsu and perfectly fused chakra with natural energy.

Hard work paid off. By the end of three years, Naruto had not only mastered senjutsu,

able to freely switch into Sage Mode, but had also evolved the Rasengan into multiple forms.

The Big Ball Rasengan's power doubled, enough to shatter solid rock; the Rasenshuriken had taken initial form. Though he could not fully throw it yet, it could unleash earth-shattering power at close range.

Besides that, he had begun to explore controlling the Nine-Tails' chakra within him.

Once, the Nine-Tails' chakra had been a wild, uncontrollable power to him. A moment of carelessness could trigger a backlash and send him into a rampage;

but after three years of tempering, he could barely suppress the Nine-Tails' will and briefly activate Nine-Tails Mode. Golden tailed-beast chakra surrounded his body, while his speed and strength underwent a qualitative leap.

His combat power had multiplied several times over compared to three years ago. Even against Konoha jonin, he could easily crush them.

Yet the obsession in his heart had never changed.

Whenever he pushed his training to the limit, whenever he broke through a bottleneck, he would think of Sasuke, their promise at the Valley of the End, and the close friend who had once fought at his side but now felt like a stranger.

"Sasuke, wait for me. I'll find you and bring you back to Konoha."

Naruto gazed into the distance, his eyes filled with determination. Because of this obsession, the chakra around him grew ever more condensed.

Completely unlike Naruto, Sasuke spent those three years struggling and transforming in hell.

After defecting from Konoha, he headed straight for Orochimaru's hideout, a castle hidden deep in the mountains and covered in strange runes.

Orochimaru looked at the cold-eyed boy consumed by revenge and curled his lips into a sinister smile. "Sasuke, as long as you obediently follow me, I'll give you enough power to kill Itachi with your own hands."

Sasuke nodded without the slightest hesitation.

He knew Orochimaru harbored ill intent and wanted to take his body as a vessel for reincarnation, but he did not care.

He had only one goal in his heart: grow stronger, take revenge, kill Itachi, and avenge the Uchiha Clan.

From then on, Sasuke began hellish special training.

Orochimaru showed no mercy. Every day, he made Sasuke battle powerful test subjects. The slightest mistake would leave him severely wounded; he also injected Sasuke with special drugs to stimulate his body's potential, while continually awakening the power of the Cursed Seal of Heaven.

Through countless days and nights, Sasuke struggled in agony.

He had been beaten black and blue by test subjects, left sprawled on the ground, unable to move or even lift a hand; he had also suffered excruciating pain from the Curse Mark's backlash, his consciousness swallowed by darkness as he nearly fell into it completely.

But whenever he was about to give up, the images of the night of the clan massacre would rise in his mind—his parents lying in pools of blood, Itachi's cold eyes, and those words: "Hate me, Sasuke, and become stronger."

That hatred became his only motivation to endure.

Over three years, Sasuke shed the youth and immaturity of his boyhood, becoming cold and resolute, surrounded by an icy aura that kept others away.

His swordsmanship grew ever more refined. Under Orochimaru's guidance,

he developed a fierce style of swordplay that, combined with Chidori, possessed boundless power;

he continuously derived new techniques from Chidori, developing Chidori Stream, Chidori Sharp Spear, Chidori Blade, and more. Chidori Stream could spread Lightning Release chakra throughout his body, forming a defensive barrier while also unleashing area attacks;

Chidori Sharp Spear could condense Lightning Release chakra into a pointed spear, piercing even sturdy defenses;

Chidori Blade infused Lightning Release chakra into a blade, making it incomparably sharp and capable of easily cutting through steel.

His Three-Tomoe Sharingan had also been trained to its limit.

Whether its insight, copying ability, or genjutsu ability,

all had reached the highest level. He could instantly perceive an enemy's movement trajectory,

predicting their attacks in advance; he could swiftly copy an enemy's ninjutsu for his own use; he could even unleash powerful genjutsu, trapping enemies in endless illusions from which they could not escape.

Moreover, his control over the Cursed Seal of Heaven had reached the point where he could activate and deactivate it at will.

He could freely enter Curse Mark State One and State Two. Upon activating State One,

black markings would emerge across his body and his chakra would surge; upon activating State Two, his body would mutate, a pair of wings growing from his back. His speed and strength would both increase drastically, and he could even briefly suppress tailed-beast chakra.

On the surface, he obeyed Orochimaru in everything and submissively accepted all special training; but in secret, he had long been gathering strength, observing Orochimaru's weaknesses, and plotting to kill Orochimaru once the three years were up and seize all his power.

"Itachi, Orochimaru, just wait."

Sasuke stood atop the castle roof, staring in Konoha's direction. A trace of icy killing intent flashed in his eyes. "In three years, I'll settle things with you both myself and reclaim everything that belongs to me."

Naruto was desperately giving chase, Sasuke was transforming in hell, while Uchiha Mu's three years had been spent laying plans in the shadows, advancing step by step.

Over those three years, he lurked within Konoha's ANBU. With his formidable strength and masterful disguise, he steadily gained a foothold, becoming a core ANBU member and earning the Third Hokage's deep trust.

But he knew clearly that ANBU was only a temporary refuge, a tool for gathering intelligence and building his power.

During his three years in ANBU, he carried out ANBU missions while secretly collecting intelligence on Konoha's upper ranks. He learned the power structure of Konoha's leadership and uncovered many of Danzo's secrets,

including how Danzo secretly cultivated the Root organization, assassinated dissidents, coveted the Uchiha Clan's Sharingan, and even maintained countless ties to the Akatsuki Organization.

But by then, he had already killed so many of them that only a few remained.