We're Best Friends

A Kekkei Genkai was created by using chakra of two attributes as raw materials, fusing them in a "chemical" reaction to produce a brand-new chakra attribute and its corresponding ninjutsu.

It was no longer a basic nature transformation like Fire Release or Water Release, but things like Scorch Release, Boiling Release, and Explosion Release.

Like sodium and chlorine reacting to form salt.

So here was the question: there were countless ninja in the ninja world who possessed two or more chakra attributes, so why were Kekkei Genkai ninja so rare?

In a vast place like Konohagakure, aside from the Senju Clan, Uchiha, and Hyuga Clan, the three bloodlines descended from the Sage of Six Paths, there was only Hayate Gekko's half-baked Transparent Release. Did that make any sense?

The main reason was the mixing ratio of the two types of chakra!

Not every ratio of chakra could produce a "chemical" reaction. Only one precise ratio could produce a specific Kekkei Genkai, as though there were some kind of "secret formula."

And aside from the ratio, there were clearly other variables that interfered with Kekkei Genkai development, such as the order in which the chakra materials were injected and their injection rates. That was why this "chemical experiment" was so complicated.

Kekkei Tōta was even more complicated. It required three attributes to react, adding an entire extra dimension of variables out of thin air. Thus, Kekkei Genkai in the ninja world could only be called "rare," while the only known Kekkei Tōta were Hashirama Senju's Wood Release and the Third Tsuchikage Ōnoki's Dust Release. (Note)

Each one was capable of sweeping across the ninja world.

If that were all, it would have been fine. The truly insane part was that even if I told you my formula, you still couldn't use it unless we shared the same genome.

If not for that trait, Kekkei Genkai could have been taught and cultivated just like ninjutsu. But now, those without a Kekkei Genkai could only start from scratch, repeatedly experimenting through trial and error to develop a bloodline suited to themselves and find their own ratio.

That was why Kekkei Genkai were usually inherited through "bloodline clans"—genes extended through kinship.

Cultivating blindly without a formula, or having the right formula but the wrong genes, usually resulted not in a "chemical" reaction but a "physical" one—I split apart.

In short, it was extremely dangerous! No one knew how many ninja had perished after taking such desperate risks.

Worse still, Kekkei Genkai cultivation was not something Shadow Clones could handle. It was precisely because it so easily caused cultivators to explode that Kekkei Genkai were so scarce in the ninja world.

In order to regain Wood Release, Konohagakure had not hesitated to encourage Senju Clan ninja to undergo the extremely lethal Hashirama Cells transplant experiments, yet it had never promoted large-scale development of new Kekkei Genkai.

The Senju Clan was the number one clan in the ninja world, yet it had nearly been wiped out by cell transplants. Konohagakure could bear losses of that magnitude, but it could not bear Kekkei Genkai development. That showed just how horrifying the latter's fatality rate was.

This was what Minato Namikaze had guided Lord Retsuo to do: develop a new Kekkei Genkai.

Thinking of Minato Namikaze filled Lord Retsuo's heart with warmth. Still, Minato probably had not expected him to begin Kekkei Genkai development so soon, had he?

According to Minato, Lord Retsuo would have to wait several years, until he had mastered chakra nature transformation and possessed sufficient chakra, experience, and knowledge to develop a Kekkei Genkai—and only then would he understand what a Kekkei Genkai truly was.

But Shinnō's appearance had made Lord Retsuo think of having Tenma provide him with Earth Release chakra!

Ho ho, becoming a First Generation Kekkei Genkai Ninja did not seem so bad, did it? After all, in all of Konohagakure's history, it had never produced a First Generation Kekkei Genkai Ninja. That would make him one of a kind!

Thus, for Lord Retsuo, the problem had been simplified to this—how exactly could the barrier control Yin Release chakra?

If developing a new Kekkei Genkai were treated as solving an equation, the greatest difficulty would be having too many variables. But if, as Minato had said, several variables could be controlled, then it really would become much easier. That was probably what Minato had meant... right?

Now, Tenma's Earth Release chakra had entered the Yin Release Barrier through the conduction apparatus, and Lord Retsuo's chakra immediately pounced on it.

He possessed Yin Release, Earth Release, and Fire Release. He skipped over Fire Release, used a trace amount of Earth Release to receive Tenma's chakra of the same attribute, then wrapped it in Yin Release. The collision of the two chakra currents immediately showed signs of swelling...

At that moment, not only was Tenma utterly bewildered, but Shinnō had frozen in place as well.

On the screen before him, the Dark Chakra containment reaction index representing Tenma shot up to an absurd level, while the one representing Lord Retsuo plunged below zero...

When Shinnō had designed this experiment, he had never imagined that he would one day see a negative number. For a moment, he did not know whether to complain about how absurdly powerful Orochimaru's equipment was or complain that his own eyes had gone blind!

Then, almost immediately, the two data trends switched places, and Tenma's rapidly dropped into the negatives...

Of course, Tenma knew that Lord Retsuo was "eating" his chakra—he devoured however much was sent over! Chakra was an extension of the body, and a ninja could feel their own chakra much like their own limbs.

Moreover, unlike releasing a ninjutsu, Tenma did not feel as though his Earth Release chakra had been released all at once and vanished. Instead, it was being lost bite by bite, bite by bite...

But Lord Retsuo was more solemn than ever, and Tenma could not help holding his breath as well.

Suddenly, a terrifying sensation surged backward through the chakra link.

What was this thing?!

Tenma nearly cried out, but immediately afterward, he felt an excitement that came from the depths of his heart! It was like an illusion of all 130 trillion cells in his body cheering at once...

Unfortunately, the feeling came quickly and disappeared just as quickly. Despite his young age, Tenma had somehow gotten an early taste of a sage's post-climax clarity.

He raised both hands and stared blankly at his fingertips. There had actually been no change at all, yet he somehow felt different from before.

Lord Retsuo remained impassive. He knew what had happened to Tenma: Tenma had received chakra that Lord Retsuo had fed back to him.

Earth Release wrapped in Yin Release was not a Kekkei Genkai, but Tenma could cultivate for a lifetime and never hope to achieve it on his own.

Tenma was a frog at the bottom of a well. In that fleeting instant, he had experienced the sensation of flying out of the well and seeing a sky and an ocean, only to fall straight back down. Naturally, his body had not changed.

What had changed was his spirit—in other words, his Yin Release.

But was this kind of forced growth really good for him? It probably would not do any harm... right?

With a loud BANG, Shinnō crashed through the laboratory doors. As he rushed over in a few quick strides, the old gentleman rapidly adjusted his expression. By the time he stood before Lord Retsuo, his face was filled with concern. "Lord Retsuo, are you all right?"

"I feel amazing!" Lord Retsuo exclaimed loudly. "What was that experiment just now? Why did it feel so good? Again, again! Don't stop!"

Shinnō thought, You're doing a handstand in a dung heap—you've gone way too far! Don't look like some junkie!

The key was, I haven't even hooked Zero-Tails up to you yet! Don't get addicted!

In the end, when Orochimaru arrived after hearing the news and received the experimental report, his expression became increasingly amused, making both Shinnō and Tenma shudder uneasily.

Meanwhile, Lord Retsuo calmly left Orochimaru's mansion with Tenma, utterly ignoring Orochimaru's almost tangible aura.

Only then did Tenma finally relax his taut nerves. His mind was full of worries; he fidgeted awkwardly, overwhelmed by what had just happened. After a long while, he finally asked, "Retsuo, just now... was that an opportunity to grow stronger? Why didn't you save an opportunity like that for yourself?"

"My Chakra isn't enough. I need someone's help. Besides, aren't we best friends?"

It was true that you had gained an opportunity, but you had also shared the risks of developing my Kekkei Genkai. There was no need to feel embarrassed.

Tenma was a cool, tsundere little pretty boy who almost never let his emotions show. Or rather, he believed he almost never let them show.

But at this moment, his facade cracked. He clenched his fists in excitement. "Right! We're best friends!"

Note:

In Naruto, Wood Release was at one point referred to as a Kekkei Genkai rather than a Kekkei Tota. It only required water and earth.

But if Wood Release lacked Yang, then where did "Yin and Yang unite to form the myriad phenomena" come from? Why did the Sharingan on Danzo's arm close, causing Wood Release to immediately lose control and run rampant?

So Yang was definitely involved. Who agrees? Who disagrees?

Those who say the author doesn't respect the original work, or even that the author has never read Naruto, might as well say Kishimoto keeps changing the settings. That's all.