In the courtyard of the Uzumaki residence, Minato and Kushina were huddled together, flirting while ostensibly researching sealing jutsu. In the distance, Nawaki was busy playing with his "flying pancake."
Witnessing this scene, Mito sighed helplessly. She wondered how a child as earnest as Nawaki could fail to grasp the simple underlying logic of the Rasengan for so long.
Three days later, Ren Kurogane finally emerged from his laboratory.
Though his eyes were bloodshot, the grin on his face was impossible to suppress. In those three days, he had cracked most of the secrets behind the exuberant vitality in Nawaki's genes. By using the God Gene to devour the Senju bloodline factors, he had significantly bolstered his own life force. Combined with his Sage Arts, he could now achieve a regenerative speed rivaling Tsunade's future Strength of a Hundred Seal—essentially, he had acquired Hashirama's legendary passive healing.
Of course, since he had already assimilated the Corpse King's factors, he technically already possessed immortality, so this was just a layer of redundancy.
What truly thrilled Ren was a discovery within the Senju DNA: a novel, recessive factor capable of neutralizing chakra attributes. It allowed naturally conflicting elements to fuse seamlessly. Ren felt as though he had stumbled upon the ultimate secret of Kekkei Genkai.
He just needed a few more days to refine the purest bloodline factors to understand why the Senju were truly called the "Clan of a Thousand Hands."
I used to think the name came from Asura having many friends and allies, leading his descendants to call themselves Senju, Ren thought. But it seems there's a much deeper biological reason!
Having not stepped out for days, Ren grabbed a quick bite to eat before heading to Mito's place to check on Nawaki. Since the kid called him "Master," he felt obligated to check on his progress occasionally.
At the Uzumaki residence:
Minato and Kushina were still deep in their private world, Nawaki's "pancake" was spinning more fluently than ever, and Mito was sitting on the veranda arranging flowers.
As soon as Ren entered, Nawaki dropped his chakra disc and sprinted over like a gust of wind. "Master! You've finally finished your seclusion!"
"Get back! Act normal!" Ren pushed the boy away with a look of mock disgust. "Did you finish the Rasengan training? You're already researching new jutsu?"
He had seen Nawaki playing with the "flying pancake" and assumed the boy was experimenting with something new. He couldn't imagine Nawaki would still be stuck on the first stage of the Rasengan.
"Uh... well..." Nawaki scratched his head, looking sheepish. "Actually, I haven't popped the water balloon yet. But I did it once successfully before! You can ask Minato if you don't believe me!"
Nawaki pointed at Minato, who pointedly ignored him. Over the last few days, Minato had realized he wasn't cut out for teaching. He had explained the core concepts of the Rasengan to Nawaki multiple times, but the boy seemed physically incapable of understanding them. It had been such a blow to Minato's confidence that he'd decided never to take a student again.
Ren nodded, greeted Mito, and then asked Nawaki to demonstrate his current progress. A moment later, Ren stared at the "pancake" in Nawaki's hand, stunned.
"Hiss! This..."
Nawaki lowered his head, bracing himself for a lecture.
However, the scolding never came. Instead, Ren's voice sounded impressed. "This isn't bad at all. Drop the water balloon; show me that chakra rotation directly in your palm!"
Nawaki snapped his head up, meeting Ren's interested gaze. His dejection vanished instantly. "Watch closely, Master! I've practiced this until it's second nature!"
He gathered chakra in his palm, and a flat, spinning disc of energy manifested!
"Not bad. The rotation speed is still too low, and it consumes far more chakra than a Rasengan, but for a monster like you with endless reserves, that's not a drawback," Ren critiqued.
Nawaki's eyes lit up. Did I accidentally invent something powerful?!
Ren extended his own hand, and an identical disc appeared in his palm. However, Ren's disc spun so fast that the resulting airflow turned into a localized miniature tornado.
"It needs refinement." With a thought from Ren, the raging wind went silent. The chakra disc in his hand looked mild, almost harmless.
But no one present underestimated it. Like the Rasengan, it had a thin "coat" of chakra containing its destructive power. Anything this disc touched would be instantly severed or shredded.
Watching his "flying pancake" reach perfection in Ren's hand, Nawaki was filled with envy. Why hadn't he thought of doing it that way?
Ren spoke up: "This is a solid move. Let's call it the Destructo Disc!"
"Destructo Disc? What a weird name," Nawaki muttered inwardly. Then he watched as Ren's disc turned stark white!
Zzzzzzt—!
The ear-piercing whine returned. Serrated edges flickered along the rim of the disc in Ren's hand. Even though they only appeared for a flash, the sheer density of the rotation made Nawaki shiver.
"It's already been upgraded!"
"This," Ren smiled, "is the Wind Style: Destructo Disc! Your logic was sound, but your rotation speed is lacking. To truly master this, you must push the form transformation to its absolute limit. Given that you haven't grasped the Rasengan in a week, I'm switching to a more 'direct' teaching method!"
"A more... what?!" Nawaki turned pale, his heart racing.
"That's right. If you still can't grasp the mystery of the Rasengan in another week, I'll have to initiate Plan B!"
Relieved that Ren wasn't giving up on him yet, Nawaki couldn't help but ask, "Plan B? What's that?"
"Plan B is Plan B. Don't ask questions."
Ren walked past him to a shaded spot under a tree and clapped his hands. "Earth Style: One Giant Water Vat Jutsu!"
Rumble!
The earth surged, and a large ceramic vat rose from the ground. Ren then used Water Style to fill it to the brim. He looked at the bewildered Nawaki. "From now on, you train with this vat."
"Uh, okay," Nawaki nodded, though he couldn't help but think: Why the hell is it called 'One Giant Water Vat Jutsu'? That's a terrible name...
Ren plunged his hand into the water. A split second later, the water inside the vat erupted as if a firecracker had gone off, splashing a meter into the air. Nawaki stared, dumbfounded.
"Replicate that within a week, and you pass. If not..." Ren didn't finish the sentence, instead turning toward Minato and Kushina.
"Minato, how is your research into the Four Symbols Seal coming along?"
On the other side of the yard, Nawaki stared at the vat, his brain working overtime trying to figure out exactly how Ren had made the water explode like that.