The next day.
Seimei woke up bright and early.
After breakfast, he left the village.
Then, using Hiraishin no Jutsu (Flying Thunder God Technique), he teleported to the island in the southern seas of the Land of Fire.
At the island's center, on top of a massive boulder, Seimei's figure appeared out of nowhere.
He glanced around, checking for anything unusual.
Finding nothing out of the ordinary, he followed his usual routine upon returning here. Raising his hands, he formed seals and activated Fūton: Kaze no Tsubasa (Wind Release: Wings of Wind) and cloaked himself in a Chakra Hagoromo (Chakra Cloak), soaring into the sky.
Then, he activated his Byakugan and began circling the island, using its penetrating vision to scan everything within a ten-kilometer radius.
Time ticked by, second by second.
About ten minutes later, he'd thoroughly checked the entire area and found no abnormalities.
Completely at ease, Seimei descended back to the island.
Wasting no time, he raised both hands, crossing them into the "Nin" seal, and cast Tajū Kage Bunshin no Jutsu (Multiple Shadow Clone Technique).
Poof!
A cloud of chakra smoke dispersed, and over a hundred figures appeared in the clearing.
Looking at his kage bunshin, Seimei efficiently divided them into groups, as he'd done countless times before.
After that, the clones split off in twos and threes, some heading to the distant beach, others venturing further out to the sea. Each found their own spot and began practicing the skills Seimei had assigned them.
Satisfied with the setup, Seimei nodded.
Then, without wasting another second, he dove into his own training.
His training was straightforward: strengthening his body.
A dense surge of Yang Release chakra gathered in his palm as he silently activated the A-rank ninjutsu Shōsen Jutsu (Mystical Palm Technique).
With a swift motion, Seimei pressed the Yang chakra into his body.
Next, he activated his Mangekyō Sharingan, triggering his right eye's dojutsu, Hito no Go (Ward of Man).
Instantly, an invisible force enveloped him.
Following his will, it began guiding his body toward evolution.
The Yang chakra he'd infused became the fuel powering this transformation.
If someone could peer into his cells at that moment, they'd see them undergoing subtle, almost imperceptible changes under the influence of these two forces.
A single change like this might seem trivial, but over time, with repetition, the transformation became profound.
There were also some unique cells in his body.
They looked identical to Seimei's own but displayed a distinct aggressiveness, as if ready to devour the surrounding cells belonging to him.
No, not "as if"—they were devouring his cells.
These weren't just any cells. They were Hashirama Senju's cells, forcibly taken from Obito Uchiha.
But this devouring process wasn't a bad thing. Seimei had chosen a unique path for integrating Hashirama's cells: assimilation.
In simple terms, assimilation meant reshaping Hashirama's cells to match his own "form."
How did he do it?
It was straightforward. He fed his own cells to Hashirama's cells, then used Hito no Go to work from both inside and out, gradually aligning Hashirama's cells with his own.
That's why Seimei saw this as a positive process.
Of course, this was only possible because he had Hito no Go, a dojutsu that gave him complete control over his body.
Without it, he wouldn't dare attempt this.
In fact, it wasn't just about assimilating Hashirama's cells. His ability to continually break through physical limits and evolve endlessly relied on this dojutsu.
While Hito no Go didn't have the flashiest presence or offer overwhelming attack or survival abilities, Seimei valued it just as much as his invincible Ten no Go (Heaven's Ward).
These thoughts flickered through his mind, but Seimei quickly refocused, pouring his full attention into guiding the Yang chakra to strengthen his body.
Time passed, minute by minute. Every so often, Seimei would cast Shōsen Jutsu again, channeling another burst of Yang chakra into his body, then use Hito no Go to steer the evolution.
When his eyes grew strained, he'd take a brief rest.
Soon, an hour had passed.
Seimei paused Shōsen Jutsu, deactivated his Mangekyō Sharingan, and recalled all his kage bunshin, absorbing and processing their training experiences and memories from the past hour.
Once he'd fully digested them, he popped a few soldier pills to replenish his energy.
Then, he launched into the second round of training.
This time, he didn't use Shōsen Jutsu or Hito no Go. Instead, he stepped off the boulder and activated Raiton Chakra Mōdo (Lightning Release Chakra Mode) to strengthen his body.
Like this, he alternated between static and dynamic methods every hour, switching up his body-strengthening techniques while absorbing his clones' training progress.
This cycle repeated, steadily elevating his abilities.
As the process continued, he could clearly feel the invisible shackles binding his body's growth growing stronger.
For anyone else, this might spell despair.
But not for Seimei. With Hito no Go as his trump card, this only fueled his drive.
Why? Because the strengthening of those shackles meant he was getting closer to the critical point of his body's transformation.
The last time his body had transformed was over four months ago.
Four months.
For someone who'd been training for less than four years, that was a long time. He'd never gone this long without a single increase in his base attributes on his status panel.
So, he was eagerly anticipating this critical moment.
But, as he'd predicted, before that moment arrived, a few of his other ninjutsu reached completion first.
One day later.
After redistributing his chakra and training for fourteen days, his Fūshin Sakkon: Keiyaku Shunshin no In (Heart-Sealing Soul Lock: Contract Instant Body Seal) leveled up first, reaching the perfect state of Lv9 (0/0).
This boosted the jutsu's effects even further.
Seimei didn't dwell on it, though.
Right away, he took the 800,000 chakra points freed up by its completion and split them evenly, allocating 400,000 to Doton: Chōkajūgan no Jutsu (Earth Release: Super-Added Weight Rock Technique) and 400,000 to Doton: Chōkeijūgan no Jutsu (Earth Release: Super-Light Weight Rock Technique).
This increased his daily chakra investment in each from 700,000 to 1,100,000, massively accelerating their proficiency gains.
As a result, the two jutsu, which would've taken two more days to level up, advanced nearly a day early. On the morning of the fourth day, they both reached Lv9 (0/0), hitting their perfect state.