Ten days later.
The Land of Fire.
The southern seas.
On the massive boulder of that island.
Seimei paused his practice of Shōsen Jutsu (Mystical Palm Technique) and Hito no Gyo (Human Control), looking up at the sky.
The sun was now directly overhead, marking noon.
With a thought, as was his routine, Seimei dispelled the Tajū Kage Bunshin no Jutsu (Multiple Shadow Clone Technique).
Poof! Poof! Poof!
In an instant, every shadow clone training across the island—inside and out—dissolved into puffs of chakra. Each carried an hour's worth of training experience and memories, flooding back into Seimei's body.
A torrent of memory fragments surged forth.
Seimei closed his eyes, carefully sifting through the information.
Then, he swiftly converted the training insights into proficiency for the corresponding skills.
Time ticked by, second by second.
Soon, a little over fifteen minutes had passed.
At one point, Seimei opened his eyes.
Visibly, a trace of fatigue lingered in his gaze.
But beneath that fatigue, there was a faint spark of excitement.
Today marked the tenth day since he completed his support mission and the fourteenth day since he began using the Four-Tails' chakra for training.
Excluding one day of routine rest, half a day spent on the rescue mission, and some chakra consumption, he'd dedicated roughly twelve days to training.
In those twelve days, his Doton: Kajūgan no Jutsu (Earth Release: Added-Weight Rock Technique) and Doton: Keijūgan no Jutsu (Earth Release: Light-Weight Rock Technique) had steadily improved. Just moments ago, both had reached the pinnacle of mastery—Level 7 (0/0).
At that moment, his understanding of Doton (Earth Release) chakra nature transformation deepened significantly.
If that were all, he wouldn't be this thrilled.
The real key was that mastering these two jutsu meant he could now develop their advanced versions: Doton: Chō Kajūgan no Jutsu (Earth Release: Ultra-Added-Weight Rock Technique) and Doton: Chō Keijūgan no Jutsu (Earth Release: Ultra-Light-Weight Rock Technique).
After over ten days of training and the insights he'd just gained, Seimei was confident. Once he mastered these advanced jutsu, his grasp of Doton chakra nature transformation would reach the threshold needed to fuse it with other chakra natures and develop a Kekkei Moura (Bloodline Encompassing).
That was what truly excited him.
Inhale… Exhale…
Taking a deep breath and letting it out slowly, Seimei calmed his racing heart.
He casually pulled a few enhanced Hyōrōgan (Soldier Pills) from his ninja pouch and popped them into his mouth, crunching them down.
As he replenished his energy, he mulled over his next training plan.
Sure, he could start developing Doton: Chō Kajūgan no Jutsu and Doton: Chō Keijūgan no Jutsu now, but Seimei knew it wouldn't be easy.
Even with the foundation laid by Doton: Kajūgan no Jutsu and Doton: Keijūgan no Jutsu, it was no simple task.
After all, Senju Tobirama's research notes didn't include any insights on developing these advanced jutsu.
Compared to the chakra nature transformation requirements of the base jutsu, these advanced versions demanded at least double the mastery.
Naturally, the difficulty skyrocketed.
Fortunately, Seimei had his proficiency panel. As long as he put in the effort, he'd see results.
Otherwise, he wouldn't have the confidence to master these jutsu in a short time.
But effort required chakra.
After some thought, Seimei decided not to tweak his current chakra allocation. He'd redirect the 300,000 chakra points previously used for Doton: Kajūgan no Jutsu and Doton: Keijūgan no Jutsu toward developing their advanced versions.
By his estimate, this approach would take three to five days at most to push these jutsu beyond their limits, evolving them into Doton: Chō Kajūgan no Jutsu and Doton: Chō Keijūgan no Jutsu and engraving them onto his proficiency panel.
From there, he could train their proficiency as usual.
Three to five days was already remarkably fast for developing new jutsu.
Take his earlier work on the cursed seal jutsu, for example. It took him a full ten days, and only the afternoon before last did he finally complete its framework and engrave it onto the panel.
With a thought, Seimei opened his proficiency panel.
There, in the skills section, a new entry stood out—Fūshin Sasō: Keiyaku Shunshin no In (Soul-Sealing Contract: Instant Teleportation Seal): Level 4 (200/2000)!
That's right. This was the cursed seal jutsu he'd developed, building on Tensha Fūin (Transcription Seal), Sasshin In (Heart-Locking Seal), and Jigyō Jubaku no In (Self-Cursed Binding Seal), combined with the Hiraishin marker.
It perfectly achieved his goals: controlling others, ensuring secrecy, and serving as a teleportation coordinate for Hiraishin no Jutsu.
A triple win.
Based on its capabilities, Seimei named it Fūshin Sasō: Keiyaku Shunshin no In (Soul-Sealing Contract: Instant Teleportation Seal).
This cursed seal jutsu had the potential to reach A-rank, with a proficiency cap at Level 9 (0/0). It was, without a doubt, an impressive skill.
Still, Seimei wasn't fully satisfied. He wanted to create a unique S-rank skill of his own, but his current knowledge limited him to this level.
That said, he already had ideas for elevating it to S-rank.
The name he chose hinted at his ambitions.
Fūshin Sasō—Soul-Sealing.
Right now, he could only achieve Fūshin—Heart-Sealing.
Using the Sasshin In and the genjutsu (illusion) capabilities of his Mangekyō Sharingan, he could implant various directives into a target when applying the cursed seal, controlling them like a mental imprint.
However, this control only affected the mind and consciousness, not the soul. If a target's soul were extracted, they could still leak secrets.
For most people, that might be enough.
But not for Seimei. He knew well that in the ninja world, death wasn't the end. Everyone had a soul, and even after death, souls lingered in the Jōdo (Pure Land).
With the right price and certain jutsu, the dead could be summoned back to the living world, questioned, or even revived.
Thus, some secrets couldn't be buried by simply silencing someone.
This made Seimei's next goal clear: achieving the Sasō—Soul-Sealing—part of the cursed seal's name.
If he could engrave the cursed seal onto a target's soul, even if they were pulled back from the Jōdo, they couldn't defy his directives.
That would ensure true secrecy.
For now, though, his research on souls was too limited to make it happen.
But he already had a plan.
Back when he couldn't enhance his Sharingan, he'd considered ways to boost his 'Spirit' attribute without it.
His answer then was Reika no Jutsu (Spirit Transformation Technique).
And now, his answer remained the same.
If he could get his hands on that forbidden jutsu and study it thoroughly, he'd likely achieve his goal.
If that didn't work, he could try acquiring Edo Tensei (Impure World Reincarnation) and draw inspiration from it to refine his technique.
Either way, his path forward wasn't blocked.
(End of Chapter)