While Izayoi and Hinata were out shopping with Hanabi…
By the Naka River near the old Uchiha district, beneath a gigantic waterfall, something was going on.
If a member of the Hyuga clan happened to be there and used the Byakugan, they'd discover a cave behind the curtain of water. Inside that cave, loud noises echoed—but the roar of the waterfall drowned them out. Touching the rockface around the falls, you'd feel periodic vibrations.
A blue-tinged glow tore through the cave's darkness. In the faint light, a blue-white sphere about the size of a basketball ballooned, then zoomed deeper into the darkness.
Boom—!
An explosion thundered, wind howled, and gravel scattered. Dust was prevented from billowing out of the cave, dispersing quickly in the blowback.
Once the air settled, yet another energy sphere formed and hurtled into the dark depths, triggering another massive blast. Clearly, the cave itself was gradually being blasted out by these energy spheres.
"The core part's finally done. Next step is to form the smaller spheres inside."
At the lit entrance to the cave stood an Izayoi shadow clone, reviewing the day's progress. He was working on the original "Super Typhoon Serial Spheres" from the TV anime—an advanced variation of the Rasengan. Izayoi had already mastered the basics, i.e., inflating a Rasengan to a size just short of the "Giant Rasengan."
It had taken him two years to get here. Only now did Izayoi truly understand why Naruto—after three years of training—still needed a shadow clone's help for Giant Rasengan.
Someone who can't even do a one-handed Rasengan would find it almost impossible to keep such a large spinning mass of chakra stable without it exploding.
Even for Izayoi, it took two solid years of meticulous practice to push his chakra control to this level. Simply gathering enough chakra to form a big sphere wasn't all that tough, but spinning that much chakra at high speed without it blowing up was a nightmare—after all, even the standard Rasengan is an A-rank technique at the pinnacle of shape transformation.
Giant Rasengan skates between A-rank and S-rank. It's no wonder S-rank jutsu are labeled as "secret arts" that cannot be learned by raw talent or effort alone.
And that's just forming a sphere the size of a basketball. The next step is creating five additional smaller spheres inside it—an effort at least as tough as Naruto perfecting the Wind Release: Rasenshuriken. Beyond that, if you try mixing all five elemental natures into those five sub-spheres, you can imagine the headache. Achieving that might put it above even S-rank, basically SS-rank. Not even Asura Otsutsuki ever accomplished that.
But that's precisely Izayoi's goal. His potential now surpasses Asura's—who had to rely on power from Hagoromo. If his Purple-tier chakra control isn't enough, he'll just upgrade it to Gold.
Once he perfects this "Super Typhoon Serial Spheres," he'll have his own signature jutsu—like Naruto spamming "Rasengan variants" against practically all enemies.
Sitting cross-legged in front of the waterfall, Izayoi's shadow clone once again gathered chakra in both hands, shaping a basketball-sized orb. This time, he didn't throw it—he just kept it stable until he drained his chakra. Then the clone dispersed in a puff of white smoke.
All of the exhaustion and training memories shot back to Izayoi's real body, who was currently feeding mochi dumplings to Hanabi. He only paused to raise an eyebrow before returning to normal, so subtle that even Hinata—who'd been quietly watching him—didn't notice a thing.
Ever since learning Rasengan and trying to create the "Super Typhoon Serial Spheres," Izayoi rarely trained with his real body anymore.
His shadow clone handled it in that hidden cave, while the real Izayoi only sparred with Hinata at their old practice ground. He was sure Hiruzen Sarutobi had used the "Crystal Ball Jutsu" to spy on him at some point.
Over the past two years, Izayoi had scheduled no-holds-barred matches with Sasuke every week or two. He knew that had to have caught Hiruzen's attention—Itachi himself reported to the Hokage before leaving the village, and even threatened Danzo.
If not for fear of alerting the Byakugan, Izayoi would have used his own Byakugan to check for any hidden Anbu.
By constantly limiting the chakra his shadow clone used, he kept the post-dispel fatigue manageable.
After Hanabi finished her mochi, Izayoi took her around town, let her ride on his shoulders using Body Flickers, or made a quick climb up trees and walked on water.
While Hanabi hadn't started formal training yet, she'd already watched Neji vs. Hinata, as well as Hinata and Izayoi's sessions.
Just like the original storyline, she aspired to become as kind and strong as her sister. Apart from having a sweet tooth, Hanabi disliked playing with other kids her age.
She preferred zipping around rooftops with Izayoi and experiencing that "roller-coaster" thrill. Once she was old enough to extract her own chakra and start real training, she'd be even clingier.
"See you later, Onii-chan!"
"Bye-bye!"
After hanging out with Hanabi until sundown, Izayoi waved goodbye to his adorable little sister-in-law. Then, instead of going straight home, he headed to the market to pick up groceries and used Body Flicker to reach the deserted Uchiha district—now inhabited only by Sasuke.
"You're here," Sasuke greeted him from the courtyard, eyes full of fighting spirit as he noticed the two shopping bags Izayoi was carrying.
"Let's eat first, then rest a bit before we spar," Izayoi said with a grin.
"Fine," Sasuke agreed.
When night fell, the two of them sat on a veranda, sharing a hot pot. Then, under the cover of darkness, two small silhouettes darted through the empty streets of the clan compound and into a nearby forest.
Smack… swoosh…
Echoes of collisions, heavy landings, and thrown objects cutting the air reverberated in the nighttime woods.
Boom—!
Before long, an explosion lit the area in red flames that were quickly extinguished. About half an hour later, the pair emerged from the forest.
Bathed in moonlight, Izayoi and Sasuke made a sharp contrast: Izayoi's clothes were neat and spotless; Sasuke's were torn and scorched, bare skin showing shallow burn marks. He was exhausted, but his eyes gleamed—he'd clearly gained something from this training.
"I won again," Izayoi remarked with a smile. "As we agreed, I get to check out your family's jutsu library."
"Knock yourself out—it's not like there's much left," Sasuke said, indifferent.
After the Uchiha Clan was massacred, the village handled the burials, and in return took most of the clan's scrolls.
Even the family's inheritance was whittled down to just a few low-level elemental scrolls. Sasuke once asked the Third Hokage about the advanced jutsu scrolls—he was told Konoha hadn't touched them, which likely meant Itachi had taken them.
Sasuke didn't really mind that the clan's scrolls were confiscated, as Hiruzen had promised him that once he became a full-fledged ninja and was ready to manage the clan, he could request the property deeds and scrolls back. Right now, he just lacks the strength to oversee them.
Izayoi believed Hiruzen was telling the truth.
Apart from restricted arts like Izanagi and Izanami, the village had no reason to covet the Uchiha's normal ninjutsu.
Just like the small inheritance Izayoi's own parents had left, there wasn't much worth "stealing."
Even so, Sasuke's jutsu library was a huge boon for Izayoi, whose shape transformation skills were refined, but whose nature transformations were nearly nonexistent.
Practicing elemental jutsu is one way to deepen your understanding of nature transformation. And if Izayoi wants to perfect the "Super Typhoon Serial Spheres," he'll need mastery of all five elements—proficient enough to fuse them into that giant swirling chakra ball.
For Wind Release, he can follow Naruto's example from canon. But the other four attributes will require painstaking study of jutsu or waiting until after graduation for a Jonin-sensei.
Of course, there's a shortcut that grants you top-tier nature transformations without any training at all: awakening the Rinnegan or the Tenseigan!