It took constant brainstorming, repeated speculation, and experimentation to make an entire ninjutsu flow as smoothly as blood through one's veins. It was not merely a matter of combining hand seals; it also had to be integrated with one's actual circumstances.
Take the forbidden technique Dead Demon Consuming Seal, for example. It required an implement like the Death God Mask to assist with its execution.
Where did such a mask come from? Naturally, it had been created by combining a soul with Yin–Yang Release.
The source of all this still had to be traced back to Hagoromo Otsutsuki.
Because he understood this point, Uchiha Kyu had finally taken an interest in research: the combination and circulation of Yin-Yang, creating life from nothing.
Aside from Kaguya Otsutsuki, Uchiha Kyu was the person most thoroughly familiar with Yin-Yang Power.
However, possessing only the ability to use Yin–Yang Release allowed one to create merely strange objects. It could not increase one's intelligence.
Creating things from thin air, combined with the many abilities Uchiha Kyu knew from his previous life, led him to choose an entirely new direction.
Kekkei Genkai.
It was synonymous with innate abilities.
Ice Release, the Hydrification Technique, Byakugan, and Sharingan all represented different kinds of abilities.
What did that mean?
How was a Kekkei Genkai born?
Naturally, Hagoromo Otsutsuki had created it inside the human body using Onmyōdō.
It was inherited through the bloodline.
Then the core of a Kekkei Genkai lay in the bloodline factors. Who would have thought Hagoromo Otsutsuki had dabbled in so many fields?
Uchiha Kyu suddenly remembered how Senju Tobirama had invented so many forbidden techniques. How could one person possibly have had so much time and energy?
Something was wrong. Very wrong.
He must have obtained some kind of inheritance or notes left behind