Mastery Over the Soul and "Lessons"

Shiki had a lot of things he wanted to take care of but first he set out to analyze the abilities he gained from taking Reika's offer to become a true Reaper. He found out that using his power as a Reaper would get him pulled into Yomi in no time so no physically ripping out people's souls quite yet. He could prolong his stay with the sacrifice of Pure Souls but not much else he could do.

While he was in reaper form, he would be utterly immune to attacks while all of his own will strike the opponent's soul for an easy insta-kill, it was a form just oozing OPness but not one without its cost. But he gained three abilities he could use in his normal form.

Reika didn't give him any names so Shiki just named them according to the Naruto world style. The first he called the Corpse Flesh Jutsu which allowed him to consume souls to refine his physical body, the second he called the Reaper's Edge Jutsu and it allowed him to create a soul reaping edged weapon of his choice which he still hadn't quite decided what its form would be.

The last one Shiki called the Soul Devouring Jutsu which allowed him to consume souls to increase his spiritual power. But that was not all, since he was neither living nor dead, even if Shiki was "killed", it would only result in him being sent to Yomi after which he could use his Mangekyo to come back as if nothing had even happened.

However, attacks that could harm souls still worked on him even in Reaper form and could actually kill him permanently and he could be sealed, although with his skills in fuinjutsu, he doubted anyone could keep him sealed for long but there were always ways so Shiki didn't have the slightest intention of letting his guard down.

Regretfully, none of his new gifts would straight up solve the problem with Shiki's soul but with his greatly increased innate knowledge and perception towards the soul, he threw himself furiously into his research trying to find a way to save his own soul through his gains from the deal.

Fully taking advantage of the time difference between Yomi and the mortal realm so that he wouldn't be missed and even then, e had soul clones taking his place just in case. Shiki did not give up until he finally found a solution. Over a week had passed in the mortal realm which meant over two months for Shiki in Yomi but he had finally succeeded.

Unfortunately, his soul was already in a critical condition and Shiki had no time to test if his new jutsu was safe to be used and had to risk using it on himself right now!

The Soul Transmutation Jutsu as Shiki named it, allowed him to modify his own soul or that of others according to his will. Shiki's plan was to use this soul manipulation power to properly fuse and blend all the souls he melded to his own perfectly.

The process was excruciatingly painful but pain was nothing new to Shiki, his repeated self torture had nearly driven him into masochism so if anything, it scared him how okay he was with pain and was even starting to enjoy it . . . A truly terrifying prospect.

In the end, Shiki's gamble succeeded and not only was his soul saved from collapse, his powers and talents also grew thanks to the perfect fusion of all the refined souls, better yet, he could now safely meld as many as he wanted with no danger at all, only benefits.

This meant that his powers perfectly melded together White Eye of the Kagura was no longer a simultaneous use of two different abilities but a single one who had its capabilities improved by the fusion. His two other doujutsu, the Ketsuryugan and Sharingan also fused with each other increasing the abilities of both.

By interacting with his elemental souls, Shiki modified them so that he would have access to any elemental combination with the exception of Yin-Yang Style which still eluded him. After this, he melded with several souls he had stocked up gaining several kekkei genkai which included but were not limited to:

Kimimaro's Shikotsumyaku, he found several damaged remains of the Kaguya clan's members in a mass grave in the Land of Water and also finished off the deathly sick Kimimaro while he was strapped to the machine that prolonged his life in Orochimaru's hideout.

The Iburi clan's kekkei genkai which allowed them to turn their bodies into smoke but without control and prone to be scattered and thus killed by any sort of wind but through the memories in those souls he found the method to perfect the ability which Shiki did by fusing all of their souls and use his Soul Transmutation Jutsu to modify the resulting soul.

Juugo's kekkei genkai which he fortunately didn't have to kill anyone for. Orochimaru had collected samples from other members of his clan once he traced their origins so Shiki was able to acquire it from their souls and rescue Juugo who was quite grateful since Shiki used seals to control his body's natural ability to absorb nature energy which was the cause of his rampages. Solving the greatest problem that haunted the peaceful man earned Shiki his undying loyalty.

Shiki got some many different new and unique abilities that he worked furiously on fusing and adapting. In the end, some of the results were a perfect body with tough skin, powerful dense muscles and super enhanced senses and nearly unrivaled self healing capabilities.

Through his infiltration of Takigakure, Shiki also obtained the Earth Grudge Fear of Jiongu notoriously used by Kakuzu. Rather than replace all his internal parts with the cursed noodles, Shiki instead weaved them through his flesh and organs drastically increasing his resistance to having limbs chopped off or being bisected.

As an added bonus, he could also move his body through the threads regardless of its state and even in normal circumstances, it enhanced Shiki's strength and toughness. He also grabbed four heart from his Soul clones which were true beings of flesh and blood and would only disperse if Shiki commanded them to and not on death. Thus Shiki got five times the chakra amount he had.

He had also gained the ability to turn into smoke, invade people's bodies as smoke and kill them form the inside out and even turn intangible. The last one was actually an upgrade of the Spirit Transformation Jutsu of Dan's. Now that he was neither living nor dead, instead of his soul leaving hi physical body, he straight up became a ghost.

Next was the matter of his Mangekyo. His constitution and self healing ensured Shiki would never lose his sight like an Uchiha would but the Eternal Mangekyo was generally more powerful and cost efficient than the regular one so Shiki wanted it anyway.

He was truly stumped on how might be able to achieve this since he had no convenient brother to steal eyeballs from and even if he had, his brother would not have a sharingan making this a mute point but then Shiki had an incredibly stupid idea that might just work . . .

'Since I can use the hearts of my soul clones for Jiongu . . . Can't I also use them for an eye transplant? I mean, they are basically my twin brothers genetically speaking so there are no better candidates . . . Or any other candidates for that matter . . .'

And so, with a gung-ho attitude, Shiki carried out this experiment and was utterly dumbfounded when it actually worked.

". . ."

"Holy Shit! Can't believe that bullshit way actually succeeded!" He shouted out loud alone in his Yomi still doubting his actual success.

His mangekyo still looked exactly the same but Shiki could feel the difference quite clearly.

Now, all he had to do was take his time to master his newfound abilities and for this purpose, he was leaving a few soul clone to stay in Yomi permanently and all of his training would be in that dimension as well.

'Well, then . . . Safe to say, other than an Otsutsuki or a Ten Tailed Jinchuuriki, I'm pretty much unbeatable maybe the likes of prime Hashirama or Madara can actually beat me but that's only because I haven't fully mastered the abilities I have. Once I do that, only a being as broken as an Otsutsuki could pose a threat but I'm far from being at my limit. I can still get stronger.'

Once he got out of Yomi and back into the world. He showed some of his new abilities to his subordinates in his desert fortress, increasing their worship of him even further and impressing the ladies that worked for him.

When Haku saw Shiki's Ice Style she felt a connection she sought for so long. During her entire life she wanted her abilities to be accepted by those around her but now she even had someone who not only cared for her but also shared these abilities and by their own choice too. Sh was of course over the moon.

Guren also got a predatory look in her eyes once she saw him use her Crystal Style and suddenly said she would be "very willing" to spend some long and "exciting" lessons, teaching her Shiki-sama on how to use this power with her impure intention written all over her face.

When Haku heard this, She too though it would be a truly "excellent" idea and also said she would be very willing to "sacrifice" the time to "teach" Shiki with a heavy blush full of impure intentions on her face like Guren.

Chino was very unhappy with not having the same excuse so she turned to Shiki with a devilishly cute expression saying they should also closely, very closely learn from each other about the Ketsuryugan they both possessed.

Karin, not willing to be left behind also wanted lessons on how to use her clan's abilities but since she was still quite young, her intentions were actually quite pure.

Zabuza was not to happy with Haku's willingness to have these lessons of a questionable nature with Shiki, fully showing his secret side of a bothersome parent towards his ward but like a rebellious teenager, Haku shut him down flat.

Shiki was looking forward to all this "lessons" with his real body. After all . . . How could these lessons be "properly" undertaken by a soul clone. No! This required a more personal touch . . .

'Hehehehehehehehe~'