"Hurry up and run!"
Tsunade smiled inwardly as she watched Sora standing there in a daze, but her face remained stern and unforgiving.
Hearing her command, Sora immediately started running in small strides.
In his memory, Rock Lee had undergone terrifying training since childhood, even without proper guidance.
Compared to that, Sora had Tsunade—the Medical Saint of Konaha—as his teacher. Surely she wouldn't let his body collapse.
With that thought, he suppressed his hesitation and ran.
"Lady Tsunade, Sora is only three years old. Isn't this too harsh?" Shizune asked, unable to hide her concern.
"He chose this path himself. Once chosen, there is no regret. Being a ninja isn't child's play. People die."
Tsunade's voice was firm.
She wasn't being cruel. She was being realistic.
If Sora endured this, he might not become a top expert—but at the very least, he would have the ability to protect himself.
"I have to hold on!" Sora roared inwardly.
His early experiences had forged an iron will. Under such brutal training, he did not complain.
He understood the scale of power in this world. It wasn't uncommon for a powerful ninjutsu to destroy an entire village.
If he couldn't even endure this, he had no right to speak of protecting anyone.
It took him more than two hours to complete the five-kilometer run.
By the end, his legs trembled violently. His body felt hollowed out.
"Continue."
A trace of reluctance flickered through Tsunade's eyes. After all, she had raised him with her own hands.
But she forced herself to stay cold.
"One… two…"
Sora dropped to the ground and began doing push-ups.
He didn't even realize how shocking it was.
A three-year-old child, after running five kilometers for the first time, still able to perform push-ups—not just a few, but dozens.
The reason was simple.
For the past three years, Tsunade had fed him the best nutrition possible.
She was from the Senju Clan, possessing an extraordinary physique.
A child raised on her milk might not reach the level of a true Senju, but he would absolutely surpass ordinary people.
Clearly, Tsunade had prepared for this long ago.
The unique ninjutsu she created three years earlier wasn't a whim—it was to lay the strongest possible foundation for Sora.
And now, as training began and Sora persevered, that hidden potential was unleashed.
For five full hours, Sora stubbornly completed every task Tsunade assigned.
His willpower was terrifying.
But his body was equally important.
Without Tsunade's nourishment over the past three years, he would have collapsed long ago.
An ordinary Earth child at age three would not have survived such training.
Yet he did.
The moment he finished, however, Sora collapsed into deep sleep.
Tsunade instantly appeared beside him using the Body Flicker Technique.
Ignoring his dirt-covered state, she scooped him up and infused Chakra into his body to examine him carefully.
Nothing serious.
Just exhaustion and muscle damage.
"As expected."
Three years ago, she had already discovered that Sora's original physique was too weak.
Without her direct nourishment, he would never have been able to walk the path of a ninja.
Now, after three years of strengthening, he might not match the Senju Clan—but he absolutely qualified as a ninja.
Senju Hashirama's cells could create miracles.
Although Tsunade couldn't compare to the First Hokage, she was still a Kage-level expert with extraordinary vitality.
Being raised on her nourishment was better than any ordinary method.
Sora might not have been born into a great clan.
But in truth, he possessed capital surpassing countless clan heirs.
He had a mother destined to become Hokage.
The next morning, Sora woke up expecting agony.
Instead, he felt refreshed. His body was light and full of energy.
"My legs don't hurt… Is this Medical ninjutsu?"
He was ecstatic.
What he didn't know was that his rapid recovery wasn't solely due to Tsunade's medical treatment.
It was also the result of the foundation she had built within him over three years.
"Stop daydreaming. Today's training is double yesterday's."
Tsunade pulled him over, checked his condition, and led him back out without mercy.
The first day was always the hardest.
Sora had survived it.
Now that he had seen tangible improvement, his resistance vanished. Instead, his fighting spirit burned even brighter.
Tsunade watched quietly, deeply gratified.
This child was far more mature than most adults.
A true prodigy.
Spring passed. Winter returned.
Three years went by in the blink of an eye.
Sora was now six years old.
Yet due to long-term training and overwhelming nutritional support, he looked closer to eight or nine.
In an open training field filled with wooden stakes, a black-haired boy about 1.5 meters tall moved like lightning.
He leapt from stake to stake, performing high-difficulty maneuvers with seamless precision.
No hesitation.
No wasted motion.
"Not bad."
Tsunade stood nearby, arms crossed beneath her impressive chest, nodding in satisfaction.
For three full years, Sora had never missed a day of training.
He had built the most solid foundation imaginable.
If he encountered opportunity in the future, his achievements might even surpass hers.
"Lady Tsunade, Sora is amazing. Your training is practically inhuman, and he never backed down once," Shizune said proudly.
"What's so amazing? This is just basic groundwork."
Tsunade clicked her tongue dismissively.
But the upward curve of her lips betrayed her pride.
"Mom, I've finished."
Sora pressed one hand against a wooden stake and flipped down lightly, landing in front of Tsunade with leopard-like agility.
Three years.
Unwavering effort.
And today, he could finally feel the results.
Though his face remained expressionless, a faint light burned in his eyes.
...
Author's Update 18+ 📢
The fanfic Naruto: Raised by Kushina, Took His Brother's Wife – Part 1 is now officially fully completed!
It is now available on Patreon for all tiers, including the lowest Tier 1.
The complete Part 1 has been uploaded on Patreon.
📚 Category: Naruto 18+
🔗 patreon.com/Shadow_demon_007
Thank you all for your continuous love, support, and patience for this story 💙