Reborn as Kaguya’s Descendant

"Haru, you can not fail today's test, under no circumstances! You hear me ?"

It was unknown whether or not the four thin fusuma walls that were enclosing the room let any noise escape up to outsiders ears, but had any Ôtsutsuki clansmen beyond the age of three witnessed the scene, no doubt it would have sprung up some old and in most cases unpleasant memories.

Under the dark sky, beneath the otherwordly but barren scenery of the moon, a millennia old stone village filled the underground landscape for a couple miles. Home of the noble lineage of Ôtsutsuki Hamura, its sole resident, the Ôtsutsuki clan, was in many ways a very unique existence.

Indeed, very few clans and individuals in the Shinobi World hailed from such legendary characters as the Sage of the Six Paths, his brother, and more importantly the otherwordly Ôtsutsuki race. And even among them, even though the moon dwellers hardly ever went down to the main planet, they were quite sure that no other clan held such a thorough legacy of their forekind, whether it's in regards to the blood or the knowledge.

Whilst one would think such a prestine pedigree would make the white eyed folk of the moon an exemplary society, the truth could not be any more different. Home to nearly three hundred individuals, Shirogakure was a ruthless place where most children got stripped of their eyes by age three.

For the Ôtsutsuki clan, nothing held nearly as much importance as bloodline purity. It was the sole factor that determined whether one would be placed in the main family, or the branch family, and it was a world of difference.

There are many, many ways a bloodline ability, also known as a Kekkei Genkai, may come to be.

Initially it is often through a first individual, but as the genes passes on through the generations, there was an increasing probability that the relevant genes that allows the manifestation of said bloodline become dilluted with each generation of mixed marital alliances. 

Whilst most lineage abilities disappear this way, for the Ôtsutsuki clan, it was a very different situation. As the most endogamous family in world history, the blood of the Ôtsutsuki clan was plagued by an opposite problem : inbreeding degeneracy. 

Even though the Ôtsutsuki retained almost all of their genetic legacy as there has not been a single mixed mariage in the clan since the grandsons of Hamura, seven hundred years of reproduction between cousins made their DNA deteriorate surely, albeit slowly. 

That was why over half a millennium ago, a caste system has been established. Only the newborns with pure and uncorrupt blood shall become the genuine Ôtsutsuki clansmen : the main family. To be deemed worthy, one would need to be possess the two main Kekkei Genkai of the Ôtsutsuki clan, the powers of both the Byakugan and the Shikotsumyaku, and a bloodline purity of at least ten percent.

If one can not manifest all of these traits, then he shall become a branch member and his Byakugans were to be stripped in order to feed the great Tenseigan, the energy vessel created by lord Hamura himself. 

So it was no surprise that no young children of the clan, barely four at the age of the test, were under great pressure to pass the later. The freedom of their lifetime was at stake, as well as their eyesight.

Unfortunately, fate is merciless, and that is why out of five children undergoing the test, only one would become main family clansman in the end. 

"I know father. Don't worry, I got this."

Ôtsutsuki Haru was confident. He truly was. Under the anxious and scrutinising gaze of his father, Ôtsutsuki Genji, his expression was indifferent, and his heart unwavering. He was reborn in this world four years ago, and whilst the memories of his previous life were slowly fading away since he was reborn, he knew what kind of existence he was.

A reincarnator, a transmigrator, whatever they were called. A kind of protagonist who transcended the regular rules of existence and was due to a glorious fate.

How could he fail so early in his new life.

And of course, how could his father know ! This wasn't something that would ever come out of his mouth anyway.

Haru knew just as well as anybody that being a tree that stood out to the wind in this world would bear no good fruits for himself if he didn't have the strength to shield himself from the misfortunes of the weather. 

He knew how ruthless this place truly was. God knows well how dearly he would have rather prefered being born in Konoha, even though he have had to go through some wars. Having superman's blood was nice, but only if you had your life to enjoy it. 

This is why since he was reborn as the son of Ôtsutsuki, prominent elder of the main family of the Ôtsutsuki clan, he stayed holed up in the household dwelling. 

There was something more to his family situation's, that may not seem so bad at a first glance. His mother, Hisame, was a branch woman. Her brown eyes didn't harm her elegance and noble demeanor in the slightest. Although she passed the purity test and had the Shikotsumyaku Kekkei Genkai, she was born without the Byakugan. Her case was unusual, as it was most often the other way around. No matter how low the bloodline purity was, even as low as four or five percent, almost all Ôtsutsuki clansmen had the Byakugan and the real hurdle was the somewhat recessive Shikotsumyaku blood limit. Normal eyes were useless for the energy vessel, and thus she was able to retain her eyesight. 

The fact that his father was a powerful figure of the main family with powerful blood limits and a sky high blood purity of fifteen percent made their union a very disturbing matter for many in this deeply traditional and archaic community. 

Such an alliance was a huge taboo in Shirogakure. To say it was frown upon would be an understatement of magnitude. Though branch and main family could be considered of the same clan, in truth for the main family members the branch was just genetical waste that was only fit to serve their noble selves.

As such, Haru's bloodline test would be under great scrutiny, because it also involved his father's standing within the clan. If he was fit for the main clan, everything would be fine. However if he was not, not only would he become a slave like so many others, it would also harm his father and his reputation would be tarnished. 

But whilst his father was somewhat anxious, his mother wasn't. She was a deeply rational person, and despite the appearances a truly fearsome warrior. It was one the main reasons the mariage was allowed to be in the first place. Among the three hundred clansmen of the Ôtsutsuki clan, she could easily rank among the top ten, even higher than his father. 

Both she and Haru knew there wasn't much to worry about for his bloodline test. He had the Byakugan since ever he was born, and whilst he had not yet undergone any training to master the Shikotsumyaku the fast healing factor of his body that was due to the excess of Yang Chakra was both a sign of superior Chakra quality and reserves, but also the Shikotsumyaku Kekkei Genkai.

The single unknown variable left was the bloodline purity, but with both his parents above ten percent, whilst the possibility of his being lower than both of them existed, it was virtually nil. 

So he wasn't very worried.

Whilst he wasn't really keen on coming out in the spot light under the gaze of his many relatives that didn't hold an ounce of good feelings towards him, he knew that it wasn't something that could be avoided. Even if everything went well as was supposed to happen, the annoyances were only starting as next he would head to the main family's academy, where he had no doubt he would still be bullied for his somewhat unorthodox lineage.

There will be tough times ahead, undoubtedly. He has yet to identify the exact timeline of his incarnation, but it should be at best a reasonable decade before the main cannon events, and at most a few decades prior as he knew from the common knowledge here that about seven centuries passed since the establishment of Shirogakure. A civil war was ahead, and then the shinobi world troubles... But great things are done steps by steps. 

For now, he needs to survive his small ordeals, and take advantage of the sole upsides of being born in this shithole : lots and lots of shinobi potential to excavate.

"We'll set off for the shrine in about an half an hour, get ready."

"Yes, father."

Haru's mid long white hair swayed as he bowed, due courtesy of properly educated folk, and retired himself in the bathroom.

As he groomed softly his hair and washed his face, he took a proper look at himself, lost in thoughts.

Seems like the peaceful times are coming to an end...

As he has never cut his hair since ever he came to this world, even though he was barely out of the baby age, his hair was already quite long and almost reached his small shoulders. Four year-old... Was awfully young. It really was something else to live compared to imagine it. He was short, weak, and had the surge to cry for stupid things. Fortunately he had some degree of self control, or else he would have lived a somewhat embarassing life till now.

As he looked at them through the mirror, he thought that his Byakugans should be good. There aren't a lot of kids his age that can withstand the burden of the heightened vision of the Byagukan without having a headache shortly after, and he could hold it for a few minutes already without overdoing it. The range was quite good as well, as he could cover almost a fifth of the village already, about two hundred meters. Compared to Neji's few tens of meters at the start of the cannon story, it was several times better. No doubts, being born out of such a lineage had its perks. It was both the result of his higher purity bloodline and his vastly superior chakra compared to basically every Hyuga ever.

As he has had more than enough time to settle down and think things through since he came here, there were a lot of things he gave some wits to think about and he had quite a few theories. Though that had to wait as there were much more pressing matters at hand, he'll eventually satiate his curiosity of the Kaguya and Hyuga clan history. 

But for now, he would let history unfold.