In addition, there was another aspect of Lightning Release that Kurogane Ren wanted to study.
That was its ability to enhance the body. This could be considered a secret technique, one typically mastered only by the Cloud Village. The fact that no other village had managed to develop it spoke volumes about its difficulty.
However, Kakashi Hatake's Chidori already contained a portion of this concept. By stimulating the body with Lightning Release, it greatly increased the user's physical activity, boosting their speed to a level even they could barely react to.
This also meant that using Chidori required either extremely high reaction speed or the ability to anticipate an enemy's movements in advance—in other words, it required the Sharingan.
Without the Sharingan, perhaps only someone like Minato Namikaze, who could freely use the Flying Thunder God Technique, would have the reaction speed necessary to fully control Chidori.
Kurogane Ren didn't believe he had Minato's reaction speed.
But he had his own advantage.
At its core, reaction speed was simply the speed of neural transmission, which relied on electrical signals.
So… if he could refine his control over Lightning Release to the level of electrical signals, he could physically accelerate his own reaction speed.
With his level of chakra control, further refinement wasn't impossible.
As he thought through everything he needed to do, Kurogane Ren let out a sigh. None of it would be easy.
On top of that, he still needed to find an opportunity to study the Ghost Bud Technique and determine how to fuse a second bloodline.
Even if the Sharingan couldn't be used after awakening, it could still serve as a hidden trump card.
There were simply too many things to do. He wished he could split time itself into multiple pieces.
Even with his Uzumaki physique, using Shadow Clones for training wasn't enough. He couldn't replicate Naruto Uzumaki's method of training with hundreds of clones at once.
Without the Nine-Tails inside him, doing that—even with an Uzumaki body—would be suicidal.
Better to take it step by step. For now, the tasks ahead didn't demand overwhelming combat strength.
Shaking his shoulders helplessly, Kurogane Ren began training with Wind Release: Rasengan.
This was a technique with a clearly documented training method in the original story. While it wasn't explained as thoroughly as the basic Rasengan, it still saved him a significant amount of research time.
That said, Wind Release: Rasengan had a very low presence. Its form was already approaching that of the Wind Release: Rasenshuriken, faintly resembling a shuriken shape.
Once Naruto Uzumaki mastered the more advanced Wind Release: Rasenshuriken, he naturally stopped using Wind Release: Rasengan.
After all, he never lacked the chakra to use Rasenshuriken.
The only time Kurogane Ren could recall Naruto using it was during a combination attack with Yamato using Wood Release to save the situation.
At first, he thought Naruto had simply misspoken, calling a regular Rasengan a Wind Release: Rasengan. But in reality, it was the embryonic form of the Rasenshuriken.
At that moment, Kurogane Ren formed a one-handed seal.
"Ninja Art: Shadow Clone Technique!"
In an instant, four clones appeared around him. Although he could create more, without Naruto's recovery ability, it was best not to overuse Shadow Clones for training.
The five of them exchanged glances and immediately began their training.
Naturally, the first step was mastering the nature transformation of Wind Release—cutting a leaf with chakra.
This wasn't particularly difficult, but since Kurogane Ren had only recently acquired Wind Release, he hadn't mastered it yet.
His approach was simple: both he and his clones would train Wind Release: Rasengan, then advance it into Wind Release: Rasenshuriken.
He understood that this method wasn't the most efficient.
Since Shadow Clones only transferred their memories and experiences back upon dispelling, there was a high chance of redundant learning.
In theory, it would be more efficient for each clone to study different techniques.
But while that would improve efficiency overall, it would delay the mastery of any single technique.
Better to master one skill than dabble in many.
So Kurogane Ren decided to first master Wind Release: Rasenshuriken as a life-saving trump card before switching to a more efficient parallel approach.
He couldn't help but sigh. He had wasted too much time in the past.
The Rasengan itself had no inherent attribute—it was purely composed of chakra. In theory, it could serve as a base to integrate various elemental properties.
Even before acquiring Wind Release, he already had Earth and Water attributes.
Logically, he could have tried integrating those into the Rasengan.
But there were problems.
First, his chakra reserves had been too low. Judging from the consumption of Rasenshuriken, even a less demanding variant would still require more chakra than he could handle.
Second, he had thought about how to incorporate Earth and Water into the Rasengan, but the ideas were messy.
For Earth Release, his initial thought was a sphere of earth. But what use was that? Eventually, he took inspiration from the Sand Village and realized it might involve sand—but even then, the power wouldn't be significant.
As for Water Release, while it could increase pressure to form cutting attacks like water blades, it couldn't compare to Wind Release's inherent cutting nature.
In the end, Kurogane Ren decided to wait until he fused Wind Release through the Ghost Bud Technique before focusing on mastering Wind Release: Rasenshuriken.
As for Earth and Water, he had some ideas—but those would have to wait until after he completed his Rasenshuriken training.
Looking at his four clones diligently working to grasp Wind Release's cutting nature, Kurogane Ren smiled faintly.
Even if his efficiency couldn't match Naruto's, being able to train with Shadow Clones at all was already several times faster than before.
While Kurogane Ren was immersed in his training, in a hidden base within the Land of Rain…
A black-cloaked figure wearing a mask appeared before a group of Akatsuki members dressed in black robes with red clouds.
Judging by their tense expressions, the masked man's arrival was completely unexpected.
At the front stood three individuals—Jiraiya's disciples. Among them was Nagato, the one who had previously detected Kurogane Ren's crow.
They were just as shocked as the others.
Konan and Yahiko both glanced at Nagato, who subtly shook his head, indicating that even his Rinnegan had failed to detect the masked man's presence beforehand.
Both of them felt their hearts tighten.
They knew better than anyone how powerful Nagato's Rinnegan was.
And yet… even he hadn't noticed.
The weight of the situation grew heavier in their minds.