How are kids in the Ninja World any different from us?
Simple on the outside they look about the same, but they're basically a whole other species.
The Ninja World is an extraordinary place: every living thing contains Chakra, a transcendent energy. A thousand years ago the Ōtsutsuki Clan planted a divine tree, and since then the entire world has been saturated and assimilated by Chakra. Not just the cells even Souls aren't exempt.
To be precise, a human body here can hold up to 130 trillion cells, whereas people back on Earth average 30–60 trillion.
That's two to four times the difference.
When it comes to childhood, Li Sen has plenty to say he's been reborn here and given a new name: Higashino Shin.
Through Higashino Shin's observations, kids in the Ninja World are much like those in his old life until age two then they hit the fast lane.
After two, both physique and intellect surge, as if some unseen force is fast-forwarding their growth.
This is especially obvious in major Ninja clans or families that have produced shinobi for two or three generations straight.
To Higashino Shin, Chakra might as well be Jinke-la fertilizer.
Probably the result of a millennium of constant warfare; in those chaotic times children were sent to the battlefield early, and anyone lacking the mindset or strength was simply weeded out.
Even after the Five Great Nations adopted the hidden-Village system and enjoyed stretches of peace between world wars, precocious kids remain common.
Here, a child acting as solemn as an adult raises no eyebrows people just figure you're gifted, maturing fast, destined for greatness.
Little white-haired Sakata Gintoki no wait, Kakashi Hatake had a perpetually jaded face, graduated the Ninja Academy at five, made Chunin at six and started cutting down enemies, causing a sensation. He became Konoha's emblem of Genius, the role model every kid studied.
Later, the famously filial Uchiha Itachi claimed his first battlefield kill at four, and by six was musing over clan, Village, and world peace did anyone object?
His father didn't guide him properly; instead he boasted about it. Sandaime Hiruzen Sarutobi even praised the boy for already thinking like a Hokage.
Now Higashino Shin has joined their ranks of early bloomers, only his precocity comes from Rebirth, carrying memories of a past life.
Compared with those two, though, he's merely steadier in behavior not jumping around like other kids yet he absolutely won't start pondering grand societal issues and seek advice from odd uncles.
He has no wish to attract attention; behind Naruto's passion lies a darkness most never see.
Higashino Shin cares nothing for world peace; reborn, he just wants to live for himself and live brilliantly.
If he dies in war someday, it'll only mean he wasn't strong, smart, or diligent enough.
If so, then die he's done it before.
More than death, he fears the mediocrity of his past life, crushed like an ant, forgotten like dust.
Land of Fire, Konoha Village.
The sun hasn't risen; the east is pale.
Apart from the bustling commercial and administrative center, the Village is ringed by dense forest, dotted with scattered buildings and numerous training grounds.
In the northwest, inside a small training field nearest a residential area, a tiny figure is drenched in sweat, grinding through basic physical drills.
A little boy with tousled dark-brown hair, fair skin, rosy lips and bright teeth cute and delicate about three or four years old.
He is Li Sen though that name is history; now he's Higashino Shin.
At the moment Higashino Shin is running laps around the field.
Training grounds inside the Village are small; one lap doesn't take long.
Maintaining a brisk, steady pace and rhythmic breathing, he counts the laps in his head.
When the target is met he switches to Frog-Hops, then hand-stand runs, still circling the field.
After that come Push-ups, Pull-ups, and more.
Beyond these, he'll later practice Kunai and shuriken throwing techniques.
Between the training ground's big trees, branches in every direction hold targets, and the steady "thwack-thwack" of Sharp Weapons striking wood rings out.
Of course, the volume of every drill is small; Higashino Shin hasn't learned to extract or use Chakra yet, and a body not yet four can't endure a heavier workload.
If he trained like Might Duy and his son or later Rock Lee he'd only cripple himself.
The ability to refine and wield Chakra divides ordinary people and Ninja into two separate existences.
Shin's current effort is preparation for that future extraction; after all, although everyone in the Ninja World has the stuff, you can't just will it into being.
Unless uniquely gifted, without early, grueling cultivation to build a strong body and focused mind, you could sit and strain until death and still produce no Chakra.
Ninja become Ninja because they endure hardships ordinary people can't.
Even the simple-minded Kizashi and the "Prince" Naruto, aside from powerful Bloodlines, sweated from childhood in private.
After each round Shin rests, following his father's method: he closes his eyes and uses his mind to imagine and sense every corner inside his body.
It's tedious, yet a step that must be repeated.
After about five minutes he starts the next round.
Only when the sun climbs and his stamina is spent does he finish the day's set goal.
By now a few older kids have arrived at the training ground.
From their looks they're Ninja Academy students.
It's spring break; these ones live near the small public ground built exactly for them.
Clan Ninja have private fields; Ninja guard their secrets jealously, especially Family jutsu and hidden techniques.
An eight- or nine-year-old girl spots sweat-soaked Shin sitting off to the side for water and curiously trots over.
"Hey, little guy, you're here early!"
"Yep, big sis. I already finished today's training." Shin tilts his head up, beaming innocently, laying the words "big sis" on thick.
The girl blossoms at the title, ruffles his hair. "Working so young tell sis, do you have some amazing dream?"
Here it comes: in the Ninja World you ask hardworking kids about their dreams; skip the ritual and you can't greet anyone.
"Of course! I'll grow strong so I can protect the Village and my comrades."
Shin tosses out the stock answer; wanting to be Hokage and the like are the lines Village kids repeat most.
Protecting comrades, becoming Hokage Konoha's most politically correct dreams, instantly showing pure will of fire.
"Such a reliable junior!" She rubs his hair again, then waves. "Seeing you so diligent makes me want to train hard too!"
"Go for it, big sis!"
The Academy students' training is far more spectacular than Shin's.
Whether shuriken and Kunai drills or sparring, their power and speed leave Shin gaping as if watching a kung-fu blockbuster.
If mere students are that impressive, how dazzling must full-fledged Ninja especially Jonin be in battle?
Surely not just pots and pans flying around.
At the very least a special-effects epic; a totally different experience from watching anime in his past life.
The real line between Ninja and ordinary people is indeed the ability to refine and use Chakra.
After watching a while Shin drags his tired body home, enjoying Konoha's busy morning scenery along the way.
Occasionally glancing up, he sees the three Hokage faces on distant Hokage Rock, sunlight gilding them in gold.