Satoru understood instantly. The White Fang wanted him to develop a new technique for quick close-combat victories. Though his Monstrous Strength was terrifying, Satoru's body wasn't fully formed yet, so a new close-range technique was crucial.
"I have Wind, Fire, Lightning—so I can learn Chidori and Rasengan."
Satoru decided on Rasengan first. After all, no seals needed, and he knew the training method fully.
This time, no System reliance—Satoru bought a water balloon and rubber ball himself. Touching the whirl on his hair, he focused, gathering chakra at the ball's center.
To speed learning, Satoru naturally used Shadow Clone Technique, this "cheat" for rapid failure experience.
In under two hours, Satoru burst the water balloon.
"Great! Next—burst the rubber ball!" Satoru was dead serious. First stage: rotation; second: sufficient power maintenance.
Satoru, also using shadow clones, tried again and again. Hatake Sakumo watched from the side with curiosity; he didn't know what new technique Satoru was trying to master.
In half a day, Satoru's chakra was depleted, but to his joy, the rubber ball burst as well.
"Thus, we've reached the third stage, that is, maintenance," Satoru could already rotate chakra and increase its power; now he needed to maintain the chakra in the form of a sphere. This stage required exceptional concentration.
Satoru trained all night. When his chakra ran out, he collapsed on the ground and rested, and upon waking, continued training. Satoru's seriousness somewhat surprised even Konoha's White Fang.
However, the heavens favor the diligent. For Satoru, who had already mastered the training method and possessed natural talent, it took less than three days to fully master the third stage.
"Excellent! Finally finished!" Satoru was covered in dirt, but his mood was incredibly uplifted.
The Rasengan from the world of "Naruto" had been mastered by him.
"Rasengan!" Satoru formed a Rasengan with one hand and then struck a large tree with it. A spiral mark immediately appeared on the tree, and in the end, the entire tree was felled.
Satoru increased his chakra output, and the regular Rasengan turned into a Great Rasengan.
Satoru resolutely gave up on the idea of creating an Ultra-Big Ball Rasengan because after the long training, his chakra hadn't fully recovered yet.
"Well, Teacher White Fang? This is the new technique I developed! Rasengan!" Satoru didn't blush at all. After all, at this time, the Rasengan hadn't been invented yet.
Hatake Sakumo nodded.
"Not bad. This technique doesn't require hand seals, has high destructive power, and I sense it has great potential for development."
"Yes, but my chakra isn't enough anymore; otherwise, it could be developed further. For close combat, it's sufficient for now. If you hit an opponent with a Rasengan, you can defeat them quickly," said Satoru.
"Not bad. Rasengan is Wind Release chakra. You could try developing it in that direction to achieve new changes. I think the power would become even greater," advised White Fang.
Satoru nodded. He was so exhausted that he fell asleep right away.
"This guy... simply incredible! Developed such a technique in less than three days!"
"If this technique is perfected, its power will probably be enormous! Konoha has another Kage-level expert! And he's only five years old!" Hatake Sakumo couldn't stop marveling as he watched from the side.
He had seen countless geniuses, but one like Satoru was naturally the first he had encountered.
When Satoru woke up, his chakra had already recovered to its peak state. He didn't immediately start new training but went to the Hokage's office for a mission. He checked every day for B-rank missions. This somewhat pleased the Third, as every teacher wants their student to strive for more.
Satoru was studying under both the Third and White Fang simultaneously, conducting his own training, and taking on B-rank missions.
In fact, this technique was originally invented by Minato Namikaze, so returning it to him would have been perfectly fine.
A year passed quickly. When Satoru turned six, the ten B-rank missions were finally completed.
The System's voice sounded again:
[Ding-ding-ding! Congratulations, Master! You've completed ten B-rank missions! You've received one chance for a surprise tenfold lottery!]
[Do you wish to draw?]
"Of course, draw!" Satoru was very happy; he had finally completed the task after a year.
[Congratulations, Master! You've received 1 billion Ryo!]
[Congratulations, Master! You've received points!]
[Congratulations, Master! You've received Chakra Fruit (weakened version)!]
[Congratulations, Master! You've received points!]
[Congratulations, Master! You've received Byakugan (can be fused)!]
[Congratulations, Master! You've received Super Body Flicker Technique!]
[Congratulations, Master! You've received a one-time chance to absorb Kage-level expert chakra!]
[Congratulations, Master! You've received +1 to chakra elements!]
[Congratulations, Master! You've received Genjutsu Reflection!]
[Congratulations, Master! You've received Genjutsu: Bringer-of-Darkness Technique!]
This time, the tenfold lottery brought Satoru a rich haul. Right from the start, he got a billion Ryo.
"What does 'Chakra Fruit (weakened version)' mean?" Satoru asked directly.
[This is the literal weakened version of Chakra Fruit. Eating the Chakra Fruit will give you very strong chakra, and your growth speed will increase!]
[You've received Byakugan. This Byakugan can be directly fused with your eyes, granting you the power of a regular Byakugan!]
[Super Body Flicker Technique is a System-modified Body Flicker Technique that will allow you to have higher short-distance movement speed.]
[Absorb Kage-level expert chakra—I think no explanation is needed? After absorption, you'll gain a large amount of chakra.]
[+1 to chakra elements means your chakra elements—Wind, Fire, and Lightning—can now add one more element.]
[You can make a choice now.]
"Then add Water," Satoru chose. His chakra elemental affinities increased by one—Water was added.
[Genjutsu Reflection, as the name suggests—you yourself aren't very proficient in genjutsu. After learning this ability, genjutsu used against you won't only fail but will be reflected. It's a very useful ability.]
[Genjutsu: Bringer-of-Darkness Technique is the Second Hokage's genjutsu. After using it, it can deprive the opponent of vision; their world will remain only darkness. Also a very good genjutsu.]
After the System explained all the rewards, Satoru immediately said:
"No time to waste; I'll eat the Chakra Fruit right now!"
"And I'll absorb that Kage-level expert chakra too!"
***
Read the story months ahead of the public release — early chapters are available on my Patreon: Granulan