Training the Multi-Shadow Clone Jutsu wasn't particularly difficult; it wasn't much more complex than the regular Shadow Clone Jutsu.
In the original series, Naruto wasn't even a Genin. He mastered the Multi-Shadow Clone Jutsu in one night by wandering around the forest with the Sealing Scroll, eventually using it to beat Mizuki.
This speaks to its relatively low difficulty level!
The reason it was classified as a forbidden technique was due to the risk of exhausting the user's chakra by creating numerous clones, which could lead to death by severe chakra depletion.
One shadow clone consumes half of the user's chakra; two leave the user with only a quarter. The chakra consumption of the Multi-Shadow Clone Jutsu is staggering!
Chakra is extracted from both physical and spiritual energy. Only someone like Naruto, with his Uzumaki lineage and the Nine-Tails, could continuously use the technique. If Kakashi were to use it, he'd run out of chakra in no time.
"Fortunately, I have my own special ability," Satoru smiled to himself.
While he didn't have the Uzumaki lineage, he had his life force field.
Because of his life force field, his body automatically adjusted to an optimal state. If he used too much chakra at once, the life force field desperately tried to replenish the lost energy.
Additionally, due to the vigorous feedback from his life force field, his chakra reserves were far greater than those of his peers, almost reaching Jonin levels.
With this buff, it would take a long time for the Multi-Shadow Clone Jutsu to deplete his chakra completely.
Thinking this, Satoru took a deep breath and began practising the Multi-Shadow Clone Jutsu.
The chakra flow was similar to the regular Shadow Clone Jutsu. Still, the release process included several additional steps, multiplying the paths the chakra took, greatly increasing the number of shadow clones.
"Tobirama was truly a genius to come up with such an ingenious chakra flow technique," Satoru marvelled.
As the chakra reached its peak, he formed the necessary hand seals and uttered the classic phrase.
"Multi-Shadow Clone Jutsu!"
**Poof! Poof! Poof!**
With a series of white puffs, Satoru was suddenly surrounded by a swarm of identical copies of himself, all looking around in bewilderment.
He felt a void in his abdomen, a hollow sensation of emptiness. Before he could act, he heard a cacophony of voices.
"Hey, why do I see so many ugly faces as soon as I open my eyes?"
"Who are you calling ugly? Look at yourself, and your eyes are like marbles!" x10
"Are you asking for a beating?" x10
"Bring it on! Who's afraid of who!" x20
...
Listening to the dozens of himself arguing in unison, Satoru felt a headache coming on.
He didn't expect the Multi-Shadow Clone Jutsu to have such a drawback, but thinking back, Naruto had several instances of arguing with his clones.
Especially during the training for the Rasenshuriken, the clones competed with each other, mocking those who made slower progress, almost resulting in a brawl.
Satoru almost laughed himself to death watching it on TV, and now it was happening to him.
"Everyone, be quiet! I summoned you. I am the original. You need to listen to me!"
Unable to bear it any longer, Satoru's scolding finally quieted the rowdy clones.
"The original? Fine, if you're the original, settle this for us. Who's uglier?"
"Yeah, settle this. Look at his nose, which practically points at the sky!"
...
Initially, Satoru wanted to say they all looked the same as him, but as he listened, he found himself unable to speak.
"Original, settle this for us. Who's uglier?"
"You're the ugliest..."
Seeing the argument escalate, Satoru took out a scroll, tossed it into the air, and with a puff of white smoke, countless shuriken, kunai, and ninja swords rained down, embedding in the ground around the clones.
This scene stunned all the clones, and they instantly fell silent.
"Whoa, is this your ability, Original?"
"Amazing, how did you do it?"
"Teach us, Original!"
Seeing the clones finally quiet down and look at him in admiration, Satoru sighed in relief and said, "Try using your mind to control the metal weapons in front of you."
"Like this..."
A clever clone tried a few times and eventually figured it out. Amidst the envious looks of the other clones, a shuriken in front of him wobbled into the air.
Satoru relaxed. As he expected, the Multi-Shadow Clone Jutsu could also use electromagnetic abilities. He had trained with shadow clones to hone his electromagnetic skills, so he figured the Multi-Shadow Clones should be able to do the same.
Seeing one clone succeed, the others weren't to be outdone and started competing.
"Damn, I won't fall behind."
"Time to show you real skill..."
"Move, move, move..."
...
Watching the clones compete, Satoru was delighted. He used the metal weapons to form a chair, leaned back with his legs crossed, and watched the starry vortex in his mind ripple.
[Electromagnetic Force Level lv2: Experience 4830/6000
4921/6000
4963/6000
5033...]
The experience points skyrocketed, quickly surpassing the 5000 mark. Satoru felt a rush of exhilaration.
As he anticipated, the Multi-Shadow Clone Jutsu allowed him to share the training experience with the original. At this rate, it wouldn't be long before his electromagnetic force upgraded to level 3.
In the original series, Naruto created thousands of clones to train for the Rasenshuriken, with the shared experience buff accelerating his progress like a rocket.
Satoru chose the Multi-Shadow Clone Jutsu precisely because of this.
Suddenly, he thought of something, and his expression turned odd.
"Isn't this like exploiting a game bug?"
Who cares! Satoru felt a sense of relief. If there's a bug, why not exploit it?
Surrounded by dozens of clones, they looked like a lush field of green onions, continuously working hard and being drained by their capitalist original.
One clone's hand trembled, causing a shuriken to veer off and hit a nearby clone.
"Damn it! Playing dirty, huh?"
The hit clone pointed at the other and cursed, but he burst into a puff of smoke before he could finish.
"After all, they are still shadow clones, one hit, and they burst."
Satoru shook his head, his hands forming seals to gather the restored chakra.
With another puff, a fresh batch of green onions sprouted around him.