Throughout the entire summer vacation, Izayoi trained together with Hinata.
Every day, he would first locate Yamanaka Ino's position, then use the Transformation Jutsu to invite Hinata out. The two of them would head to an abandoned training ground, where they would either practice tree-walking or engage in hand-to-hand combat.
Having found friendship and regained her confidence, Hinata underwent an astonishing transformation over the summer.
Not just in strength—but in demeanor as well.
The first person to notice the change in his eldest daughter was Hiashi Hyūga.
When he learned that Hinata was practicing water-walking, he realized that she wasn't just going out to make friends and play.
Izayoi, on his end, also noticed someone was secretly watching him and Hinata.
But he didn't try to hide; instead, he planned to use the opportunity to test Hiashi's attitude.
That day, Izayoi found a reason to demonstrate to Hinata how to walk on water.
He also showcased the Shadow Clone Technique, a basic Wind Release, and utterly crushed Hinata in their taijutsu sparring.
The next day, Izayoi again transformed into Yamanaka Ino and went to the Hyūga compound to invite Hinata out.
The moment he saw Hinata step out, he understood Hiashi's stance.
The clan head of a noble family had tacitly approved of Hinata training with him.
Izayoi's background was no mystery to the ninja clans.
A civilian orphan from a ninja family, not even through three terms of his first year at the academy, and he had already mastered tree-walking and water-walking—techniques not taught in school—as well as the Shadow Clone Technique and basic Wind Release.
That kind of talent and chakra reserves undoubtedly marked him as a civilian prodigy of this era.
Training alongside such a prodigy would greatly motivate Hinata.
This was evident in how hard Hinata practiced water-walking at home, as well as the transformation in her personality and presence.
Although Hiashi had long been disappointed in his eldest daughter's performance, having yet to discover Hanabi's talent, he had not given up on Hinata or decided to shift his focus to his younger daughter.
Seeing that a single friendship could bring about such a dramatic change, Hiashi felt nothing but joy.
As for thoughts of breaking them apart—he had none.
First, the two of them were still very young, and this seemed like pure friendship for now.
Second, in his eyes, there was no future between Izayoi and Hinata.
The Byakugan of the Hyūga clan could not be allowed to be passed on outside the clan.
Izayoi was just a tool to help change Hinata.
He would closely observe their relationship. If things began to shift between them, Hiashi would step in and make them face the harsh reality.
Unless Izayoi became an exceptional figure—someone on the level of the Fourth Hokage, Minato Namikaze—they would have no future.
Neither Izayoi nor Hinata knew any of this.
Seeing that Hiashi wasn't stopping him from spending time with Hinata, Izayoi let go of any concerns and focused on teaching her the Three Basic Jutsu and chakra control techniques, while also using taijutsu matches in an attempt to trigger Hinata's red talent trait.
This summer, both Izayoi and Hinata reaped great rewards.
Hinata had already mastered tree-walking and water-walking, and had also learned the Three Basic Jutsu.
However, likely due to her insufficient chakra reserves, she had not yet mastered the Shadow Clone Technique.
In addition, her chakra point strikes had improved significantly.
Izayoi had a talent trait labeled "Medical Genius."
His mother in this life had been a medical ninja, and her legacy included scrolls on basic medical ninjutsu, which Izayoi had long since mastered.
To try and unlock the Byakugan Princess's red talent trait, Izayoi—aside from going easy for the first few days to help Hinata adjust—was ruthless afterward, thoroughly beating her in their taijutsu spars.
After the fights, he would then heal her.
Even though both were sparring matches, Hyūga Neji—despite his hatred for Hinata—never dared to truly hurt her with Hiashi Hyūga watching nearby.
Izayoi, however, fought for real, showing no mercy just because she was a girl.
No matter what, he would beat her first and coax her later.
As Hinata kept taking hits, her real combat experience naturally skyrocketed. Her strikes became more decisive, and she had no hesitation injecting chakra directly into Izayoi's body.
Now used to being healed after each beating, Hinata would never again be like her original counterpart—so kind-hearted that she couldn't bring herself to injure her younger sister, and thus lost to a girl five years younger than her.
It was precisely this stark transformation that made Hiashi fully permit Izayoi and Hinata's "meetups."
Although Izayoi didn't manage to trigger the red talent tag [Byakugan Princess] this summer, his own growth was just as significant.
Through taijutsu sparring with Hinata, Izayoi had secretly learned the Hyūga clan's chakra point striking technique.
After probing Hiashi's attitude, Izayoi used "guidance" as an excuse to have Hinata secretly bring him a diagram of human chakra points and a scroll on the chakra point strikes.
Izayoi now fully understood the layout of human chakra points and the technique of injecting chakra to block an opponent's flow.
While he wasn't interested in the Gentle Fist's Eight Trigrams style, the technique of disabling a person's chakra flow by striking specific points intrigued him greatly.
It could be unexpectedly useful in real combat.
Even though he didn't unlock a red tag this summer, Izayoi still extracted two talent tags from Hinata.
One was the blue tag [Chakra Control], which he already had himself.
At the time, a notification rang in Izayoi's mind:
"Ding! You have obtained the talent tag [Chakra Control (Blue)]. It overlaps with your existing talent tag. Would you like to fuse or dismantle it?"
Izayoi chose to fuse it.
After fusion, the Chakra Control tag didn't evolve to purple; it remained blue.
Even so, Izayoi noticed a significant improvement in his chakra control skills.
At that moment, Izayoi finally understood why Sakura Haruno was able to surpass Hinata, who had been training in Gentle Fist since childhood, and even Shizune, who had studied under Tsunade since a young age, all within just three years.
It was just like how both lines carried Ōtsutsuki blood, but the Hyūga clan couldn't compare to the lineage from the moon.
Even among Chakra Control tags, the difference between blue and purple was like night and day.
Even fusing two blue [Chakra Control] tags couldn't reach the level of a purple tag.
In contrast, the purple [Chakra Control] tag allowed Sakura to master advanced medical ninjutsu within three years, access the explosive chakra of the Senju clan, and even learn the S-rank Yin Seal and Strength of a Hundred Technique.
Aside from [Chakra Control], Izayoi also extracted a purple tag—[Kekkei Genkai: Byakugan].
Unfortunately, a kekkei genkai is just that—a bloodline limit. The "Byakugan Princess" was something else entirely.
Without already possessing the kekkei genkai [Byakugan], that tag would've only granted him the eyes themselves, not the purity of Hinata's Byakugan.
Izayoi chose to dismantle that tag.
If he had fused the Byakugan tag, his Byakugan purity would likely have increased.
But awakening the Tenseigan would be impossible.
Just like how fusing two blue [Chakra Control] tags couldn't reach purple, the Tenseigan required far more than just merging a few Byakugan.
The Ōtsutsuki clan had to sacrifice all the branch family's Byakugan to create the final form of the massive Tenseigan—possibly even incorporating the main family's eyes as well.
Given the purity of the Ōtsutsuki clan's bloodline, their Byakugan far surpassed that of the Hyūga clan.
For Izayoi to evolve his eyes into the Tenseigan through fusion, who knows how many tags he would need to combine.
Fusing just two would be a waste.
Izayoi didn't lack purity to begin with.
After dismantling the purple [Kekkei Genkai: Byakugan] tag, Izayoi gained over a thousand points, and his status panel changed:
> [Host: Izayoi]
[Talent Tags: Ōtsutsuki Bloodline (Red), Kage-level Potential (Gold), Kekkei Genkai: Byakugan (Purple), All-Attribute Constitution (Purple), Medical Genius (Blue) [+], Chakra Control (Blue) [+]]
[Points: 1791]
The plus signs behind Medical Genius and Chakra Control meant they could now be upgraded.
That's what the points are for.