A Transmigrator's Story in the Hyuga's Main Branch

Hikari wasn't just relieved to be born into the Hyuga clan because he avoided the kind of extermination he would have faced if he had been reborn into the Uchiha clan, for example.

He also believes that, in terms of their current strength and potential, the Hyuga clan is on par with the Uchiha clan at this point in time. This is contrary to the popular belief held by readers of Hikari's previous life, who generally viewed the Uchiha as the stronger of the two.

After everything he learned in these few days, Hikari now considered the Byakugan to be a far more valuable dojutsu than the One-Tomoe Sharingan and even more powerful in terms of pure vision and insight than even any higher version of the Sharingan in existence.

Sharingan's mastery of insight and vision differed from the Byakugan's in that it primarily involved 'superpower-like' pattern recognition and memory recollection of observed patterns.

This is why, historically, the Uchiha clan leaned heavily on skills like shinobi weapon throwing, kenjutsu, and, most importantly, ninjutsu, even developing strong affinities for fire, mainly, and lightning, secondary releases over time.

Their vision facilitated the easy copying and learning of ninjutsu over generations, leading them to develop fighting skill sets around it, unlike the Hyuga, who, with their internal and 360-degree vision, honed the Gentle Fist technique and mainly used ninjutsu as a supplementary skill.

Therefore, while the Uchihas might not have had as diverse a range of visual abilities as the Byakugan, their unique talent allowed them to excel across various combat disciplines, truly mastering ninjutsu on the way higher level.

However, without the second gift from the Sharingan—a heightened affinity for Yin Release, which was related to genjutsu—the Uchiha would still have been outmatched by the Hyuga.

With this enhanced capability for genjutsu, the Uchiha became the strongest users of such techniques in the world, surpassing the Hyuga in this domain by far. So, only with their prowess in both ninjutsu and genjutsu could the Uchiha be on equal footing with the Hyuga.

That exact affinity for Yin Release and genjutsu was also why they got famous for being able to control 'Tailed Beats'.

In fact, Hikari classified the Sharingan more as a vehicle of 'Yin Release' affinity altogether rather than placing it in the same category as the Byakugan in terms of eyesight 'buffs'.

The requirement of experiencing strong emotional pressures to awaken the Sharingan spoke volumes to its true nature, aligning it more closely with Yin Release and spiritual elements rather than the eyesight and biological aspects characteristic of the Byakugan. 

The clearest example of how the Byakugan is more 'biological' and the Sharingan more 'spiritual' can be seen in how easily the Byakugan was transplanted to a non-clan member, Ao, in the original story.

Ao could activate and deactivate the Byakugan at will and use it with minimal chakra expenditure, almost as if he were a native Hyuga.

In contrast, the Sharingan proved to be much more challenging to use when transplanted into non-Uchiha like Kakashi.

It couldn't be turned off at will, controlled easily, and it drained significant amounts of chakra and caused fatigue, which limited Kakashi's potential.

It was because the biological systems of all humans were way more similar than their souls, leading to much easier integrations and vice versa.

Therefore, the so-called shinobi "bloodlines," including the dojutsu, were also related not only to physical but also to spiritual inheritance (soul) from your parents from birth. 

This difference in usability also led the Uchiha clan, unlike the Hyuga, to not use any special jutsu to safeguard their eyes.

The Uchiha likely felt secure in the knowledge that the Sharingan's demanding nature made it almost impossible for non-Uchiha shinobi to use it.

Meanwhile, back on topic, Hikari believed that the two and three tomoe stages of the Sharingan should be considered more 'valuable' and stronger than the Byakugan, a departure from the assessment of the one-tomoe stage.

This belief stemmed from the fact that advancing to the two and three tomoe Sharingan not only retained the advantages of the previous stages but also significantly boosted the user's spiritual energy.

This increase in spiritual energy, in turn, expanded the user's overall chakra capacity. Since spiritual energy is typically more challenging to cultivate and often lags behind physical energy in development, users were previously unable to convert all their physical energy into chakra efficiently. 

However, the Sharingan's enhancement of spiritual energy bridged this gap, allowing for a more effective conversion and utilization of chakra.

Consequently, users of the two and three-tomoe Sharingan generally possessed greater strength than the average Byakugan wielder. The presence of a three tomoe Sharingan nearly guaranteed the status of an Elite Jonin, while two tomoe were synonymous with Jonin level, and one tomoe indicated a Special Jonin.

In contrast, possessing the Byakugan did not automatically confer a Jonin ranking; many Byakugan users in the Hyuga clan were Chunin. Even among those who reached the Jonin level, the Byakugan often designated them to more supportive rather than frontline combat roles. 

But, getting to the two and three tomoe levels of the Sharingan was really tough, while most of the Hyuga clan, about three out of four people, could unlock the Byakugan. So, this kept the two clans pretty much even in terms of power.

The fact that not many Uchiha could reach the higher levels of their Sharingan meant that its full power was rare. Meanwhile, because so many Hyugas could use the Byakugan, their strength was more spread out across the clan. So, this still kept the two clans 'balanced'.

However, in Hikari's mind, what really made a difference in how strong the two clans seemed was the existence of the Mangekyo Sharingan. Just waking up with this power could bring someone to a 'Kage-level' automatically with all those special overpowered abilities and the boost in chakra.

The Hyuga clan could match the Uchiha at the lower levels, and even at the very top levels, Hikari thought that the Tenseigan and Rinnegan were equally strong. But it was those higher middle stages where the Uchiha clan had an edge and more potential.

Yet, Hikari was convinced there had to be some hidden reason why the Hyuga didn't have a way to take the Byakugan to a higher level in a similar way. It just didn't make sense to him that such a possibility wouldn't exist.

Hikari already figured out that the Cursed Seals played a part in this mystery. He now knew firsthand that the Curse Mark reduced the Byakugan's powers in the Side Branch members.

But this raised another question: Why hadn't anyone from the Main Branch managed to evolve their Byakugan to higher levels, similar to the Mangekyo Sharingan?

The existence of the Curse Seal raised two significant questions for Hikari. The first was about its true purpose. It was clear to him that its use extended beyond merely protecting the Byakugan.

If protection was the sole reason, there wouldn't be a need for such a harsh measure as the brain destruction command embedded within the seal. This led Hikari to believe that the development of the Curse Seal was prompted by circumstances or threats that required such an extreme response, not just the fear of the Byakugan falling into the wrong hands.

The second mystery that puzzled him was why no one from the Main Branch had ever unlocked further abilities of the Byakugan, akin to the evolution of the Mangekyo Sharingan. 

This is why Hikari was convinced that there must be multiple shocking secrets buried in his clan's history. He was determined to uncover these secrets over time. He believed that understanding these hidden aspects of his clan's past might reveal the potential for the Byakugan's evolution or at least explain why such an evolution hadn't occurred yet. 

In fact, Hikari came to realize that there might not even be an evolution akin to the Mangekyo Sharingan for the Byakugan. Instead of having distinct, binary visual transformations, the Byakugan's power lay in its 'purity' and the potential for incremental improvement.

This understanding led Hikari to focus intensely on training his Byakugan, hoping to gradually unlock new abilities over time.

He entertained the hope that perhaps, with enough dedication and refinement of his dojutsu's purity, some new powers could manifest, possibly even suddenly overnight.

However, when Hikari was born, unlike the decades before or after the original story, there were no Mangekyo Sharingan holders in the Uchiha clan. This unique situation meant that the Hyuga and Uchiha clans could genuinely be considered of similar strength.

Yet, the Uchiha, proud as they were, would never admit to this parity. Meanwhile, the Hyuga preferred to stay out of the limelight, adopting a strategic policy of keeping a low profile. As a result, this balance of power wasn't widely recognized among the general populace.

This assessment didn't even take into account the possibility that the Hyuga clan harbored more hidden secrets or 'weapons', as Hikari theorized.

If his theory held true, then no one outside the few people placed at the top of the Hyuga clan truly knew the full extent of their comprehensive power in the Ninja World.

Regarding sociological factors that might influence the overall strength of the two clans, both had their share of internal issues.

The Uchiha clan, with its deep emotional ties to the Sharingan, has experienced civil strife and internal conflicts throughout history. Notable divisions into 'doves' and 'hawks' in recent decades and the civil war during Madara's defection are included.

These ideological splits often led to tension and discord within the clan, impacting its unity and, by extension, its overall strength.

On the other hand, the Hyuga clan faced a different set of issues stemming from the division into Main and Side Branches, which happened for some more tangible, mysterious reason in Hikari's speculation.

Over time, the Main Branch became somewhat complacent, indulging in the privileges and comforts of their status.

This indulgence led to a loss of the rigorous discipline and drive that might have propelled them to greater heights of power.

Conversely, members of the Side Branch often felt demoralized and oppressed, burdened by the Curse Seal, and aware that no matter how hard they trained, they would never be able to rise to the top of the clan hierarchy.

This resulted in a lack of motivation to push themselves to their limits. Meanwhile, the Main Branch lacked motivation for a different reason—they already had everything they needed and saw little reason to strive for more.

This lack of a 'middle ground' between the driven and the complacent further exacerbated the clan's internal issues, affecting its potential to grow stronger as a unified force.

This also doesn't consider that the Hyuga clan didn't have powerful Indra and Ashura reincarnations every few generations, which gave rise to many overpowered individuals inside the Senju and Uchiha clans, making them considerably stronger than the Hyuga clan during the Warring States period, for example. The last two were 'demigods' like Hashirama and Madara just a few decades ago and also probably the two strongest reincarnations.