The scenery before him suddenly shifted, and Seimei found himself back on the familiar island.
Standing atop a massive boulder, he took in the familiar surroundings but didn't rush to put his ideas into action. Instead, he started by performing a ninjutsu technique—Wind Release: Wings of the Wind!
Whoosh!
Without a sound, a pair of chakra wings appeared on his back.
With a light flap, Seimei shot up into the sky.
Once airborne, he formed another set of hand seals, deactivating the "Guardian Seal" on his forehead. Then, he focused his energy and activated his Byakugan.
Instantly, everything within a one-kilometer radius became visible to him.
He flew around the island several times, expanding his surveillance area to a few kilometers. After thoroughly scanning the surroundings and confirming there were no threats, he descended back onto the boulder.
Caution was just part of Seimei's nature.
With everything in check, he formed another set of seals and activated Multi-Shadow Clone Jutsu.
Boom!
With a burst of chakra-infused smoke, twenty identical clones appeared.
Without wasting words, Seimei immediately ordered his clones to start experimenting with "Universal Sealing Technique", using himself as the foundation to construct the chakra reservoir he envisioned.
Since the process involved altering his own body, even though his Universal Sealing Technique had already reached Level 7, Seimei didn't take any reckless risks. Instead, he had his clones conduct the trials first.
This way, even if something went wrong, he wouldn't suffer any direct consequences.
And as it turned out, his caution paid off.
Only a few minutes had passed before one of his clones failed and collapsed.
Poof!
The clone instantly vanished in a puff of smoke, returning its accumulated chakra, experiences, and memories to Seimei's main body.
Back on the boulder, Seimei closed his eyes, carefully reviewing the failed clone's entire process, hoping to pinpoint the root cause of the mistake.
However, before he could fully analyze it, two more clones suffered the same fate.
One after another, more than half of the clones disappeared in quick succession.
The remaining clones, seeing their counterparts fail, slowed their progress, cautiously proceeding with their attempts.
Seimei frowned. He didn't want to waste too much time on this.
Determined, he absorbed the memories from all the collapsed clones and immediately dispelled the Multi-Shadow Clone Jutsu, retrieving the remaining clones.
After fully syncing with their memories, he formed the hand seals again—Multi-Shadow Clone Jutsu!
Boom!
A fresh set of twenty clones appeared, and a new round of testing began!
Thanks to his past experience sealing the Seven-Tails, Seimei quickly honed in on the key issues despite repeated failures.
Unlike the pure and relatively stable metal spheres he had worked with before, the human body was in a constant state of change. Even though these changes were minor, they were significant enough to disrupt a high-precision sealing technique like this one.
That was why the clones kept failing.
Under these circumstances, the best solution was to increase the level of his Universal Sealing Technique.
If he could max it out, reaching a level where he could manipulate it effortlessly, then these small fluctuations would be a non-issue.
But Seimei didn't have that kind of time.
So, he needed some additional support.
With this in mind, Seimei opened his eyes and returned to a nearby wooden hut. He retrieved a spare scroll, along with a brush and a special type of ink.
Just like yesterday, he unrolled the scroll, dipped the brush in ink, and carefully transcribed the Universal Sealing Technique onto the scroll in the form of a sealing formula.
Once the transcription was complete, he stepped into the center of the scroll without hesitation.
"Inhale… Exhale…"
He took a deep breath, calming his mind.
Then, without any further delay, he activated the Universal Sealing Technique written on the scroll.
As a surge of chakra flowed into the scroll, the sealing inscriptions began to glow faintly, as if coming to life, and even showed signs of detaching from the parchment.
Seeing this, Seimei shouted with authority, "Rise!"
In an instant, all the sealing inscriptions lifted off the scroll and rapidly arranged themselves into a hollow, spherical formation around him.
He carefully sensed the seals floating around him. Once everything was in its proper position, he changed his hand seal and proceeded with the final step.
The sealing inscriptions gradually converged toward his body, making contact with his skin before sinking in. Finally, they all gathered at the center of his forehead.
Seimei focused, carefully guiding the inscriptions into the designated positions within his body.
This was the additional support technique he had envisioned earlier.
By pre-recording the Universal Sealing Technique onto the scroll, he could greatly reduce the mental strain required to execute it.
Now, all he needed to do was concentrate on guiding the seals to completion, significantly increasing the success rate.
Of course, the only reason he dared to attempt this directly on himself was because his clones had already eliminated most potential risks.
Even if some unexpected problems arose, he was confident he could handle them.
As it turned out, things went even smoother than he had anticipated. Though there were minor hiccups, they were all easily resolved on the spot.
Before long, Seimei successfully completed the construction of his chakra reservoir.
At that moment, a silver-white, eight-trigram-like symbol formed around his Byakugan on his forehead.
This was the external manifestation of the Universal Sealing Technique.
Focusing his mind, Seimei extended his spiritual awareness into the seal, and he immediately sensed a stable, well-structured space inside.
Without hesitation, he concentrated his chakra and began testing the reservoir's functionality.
Drip… Drip…
Like drops of water, liquid chakra began forming out of thin air, collecting at the bottom of the sealed space.
This confirmed that the storage function was working properly.
Now, the next question was capacity.
According to his plan, he wouldn't be using the chakra stored from the Seven-Tails for a while.
At its current rate, the Seven-Tails saved 400,000 chakra points per day—which meant 4 million points in just ten days. If the reservoir couldn't handle that much, it would be pretty useless.
With that in mind, Seimei continued channeling chakra into the seal.
Minutes passed.
Soon, a thin layer of chakra liquid formed at the bottom of the sealed space.
Based on his system's calculations, this initial amount was around 1,000 chakra points.
By estimating the total size of the space, he determined that its maximum capacity was about 5 million chakra points.
That was over three times the total chakra of the full-power Seven-Tails, and roughly 12–13 times his own chakra limit.
It was definitely a huge amount.
But even so, if he continued storing the Seven-Tails' chakra daily, the reservoir would fill up in less than two weeks.
However, Seimei wasn't too worried.
For one, two weeks was plenty of time to push the Universal Sealing Technique to Level 8 and expand the reservoir.
And more importantly, he had another purpose for this chakra reservoir—one that could potentially consume large amounts of stored chakra.
With that thought, Seimei adjusted the sealing formula, linking the reservoir to his Byakugan.
Immediately, a refreshing sensation spread through his forehead.
Without realizing it, Seimei closed his eyes.
At that moment, it was as if his Byakugan was being nourished by an unseen force, triggering rapid evolution.
Following instinct, Seimei activated the Universal Sealing Technique, massively drawing chakra from his reservoir.
Drop after drop of chakra materialized, merging into the space before being absorbed by the seal—then converted into a higher-energy form and transferred directly to his Byakugan.
Bit by bit, his chakra became fuel for evolution.