Two Years Later and Hinome's Breakthrough

Another two years had swiftly passed, and thirteen-year-old Hikari Hyuga stood casually outside one medical trial room's imposing glass wall inside his large personal residence while glancing inside expressionless.

Inside, now fifteen-year-old Hinome Hyuga, clad in the emblematic white medical coat of a researcher, was meticulously observing five Side Branch members on whom they had previously performed certain experiments.

With her analytical gaze, Hinome moved from one clan member to the next, taking biological samples, employing an array of medical equipment for inspections, and conducting interviews with cold professionalism.

As the last of the subjects left the room, Hinome began to review the amassed paper data, her eyes scanning for patterns and anomalies with a scientist's rigor. It was then, in this moment of focus, that Hikari stepped inside, his entrance silent but his presence undeniable.

"Hikari... After this final check-up and assessment, it can be said that our patented procedure is truly empirically proven to work now...", Hinome began, her voice echoing with a blend of triumph and seriousness.

"This small group of Side Branch members truly didn't experience any significant side effects and truly accepted those various foreign cell types into their bodies and assimilated them almost perfectly. These individuals all physically and mentally acclimated well since the last procedure of the series was performed a month ago.",

As Hinome turned around to face Hikari, her previous stern and analytical look of indifference softened and became more gentle unconsciously. 

"I'm relieved now. This is truly a great achievement, Hinome; you should be proud of yourself. You are probably the only one currently in the world capable of performing that kind of procedure. Next... it is just about finding the right kind of 'material' for transplantation then, and it is my job...",

Hikari's words trailed off slightly as he allowed himself a small, sincere smile, a rare occurrence for him.

He then took a seat opposite Hinome, indicating his readiness to delve into the details of her final assessment. As he read it, his attention turned towards the data that lay between them.

Over the last year especially, Hikari, thanks to his status and relationship with the Patriarch, got the green light to run some secret tests on many Side Branch members under his care.

Hinome was mainly in charge of these experiments. Hikari helped out as much as he could, but his understanding of science was pretty basic compared to her. Hinome, on the other hand, was all about science and medicine.

She didn't get distracted by other things like Hikari, who had a lot on his plate. However, that didn't mean Hikari didn't grasp some key concepts, which allowed him to understand the fundamental key concepts from her research.

At the start, things didn't go smoothly. Some of the Side Branch members got hurt, and there were even a few who didn't make it. Scary injuries and weird changes were happening to people. But Hinome and Hikari didn't give up.

They kept looking at what went wrong each time and learned from it. Hinome worked hard to make the experiments safer and more efficient, now finally mastering them on the level that they both deemed most optimal and satisfactory.

The process essentially started with Hinome mastering the critical techniques of spotting and selecting the most suitable cells from an individual. Using Byakugan's unique microscopic vision, she could observe and choose cells with unparalleled precision.

This vision, combined with her adept use of Yang Release and meticulous chakra control, allowed her to nurture and then modify these cells from the 'inside'.

She was able to strip them of any potentially harmful individual characteristics that could lead to adverse reactions upon transplantation while carefully preserving their inherent vitality and potential for enhancement if present or other 'positive' characteristics.

This intricate procedure transitioned into actual transplantation experiments on mice during the first year, and by the second year, the process had progressed to human trials, where Hinome refined and perfected her methods based on the learnings from the initial phase.

The procedure was carried out in two critical steps: targeted injection and systematic injection. Targeted injection was the initial phase, where specific areas or systems within the body were addressed.

For localized enhancement (e.g., an arm), chakra could be used to create a concentrated area where foreign cells were more densely integrated, providing specific enhancements like increased strength or durability in that limb.

For systemic enhancement, a more distributed approach was needed. Foreign cells were introduced at key points throughout the body. Over time, these cells spread and multiplied, aided by the host's chakra, to ensure a balanced enhancement across all physical and chakra systems.

However, the true challenge—and Hinome's ultimate goal—was mastering that second method. This method, though significantly more complex and demanding, promised a more comprehensive and effective integration of the new cells into the host body in a holistic way.

Systematic injection required a further nuanced understanding of the human body's immune response and the intricate balance needed to introduce foreign cells without triggering adverse reactions.

Hinome's dedication to perfecting this method paid off. She was able to achieve a seamless integration of cells, enhancing the body's capabilities without the side effects that had plagued their early attempts.

"I never thought that we would have achieved the ability to transplant foreign cells into different bodies so easily, despite the supposed genetic differences of said cells. It's all thanks to the mysterious nature of chakra, and especially Yang Release, allowing us to directly bypass those differences...",

Hikari analyzed thoughtfully and added mentally, 'It is truly a different world than my last life.'

His admiration for Hinome's skills was evident as he considered the complexity of her work, "Of course, this wouldn't be possible without Hinome's mastery over medical Yang Release and the surgical precision your Byakugan's microscopic vision provides while you perform.",

"This precision is critical not just during the extraction and cultivation of cells but, most importantly, during their introduction into a new body. To avoid potential overgrowth, incorrect placement, rejection, or any other form of biological chaos, extreme real-time observation and precision are indispensable ...",

Despite his limited knowledge of biology, Hikari found a way to grasp the essence of their breakthroughs, likening the cultivated cells to what would be known as stem cells in his previous life in his mind. However, in this world, the transformation process leaned heavily on manual techniques and chakra manipulation, with advanced equipment playing a lesser role.

"Yes, Hikari, but that's also what limits its applicability on a broader scale. As I'm the only one who can carry out most of it, it directly inherently restricts how many people we can affect.",

"We're looking at a capacity of maybe 5-10 individuals a year without compromising the process and risking side effects...", Hinome explained, her tone pragmatic, devoid of much regret for the wider clan. She was just a little regretful about the lost benefits they could've gained from introducing this procedure on a wider range and their standing within the clan.

"However, then I still wouldn't be able to focus on anything else that we talked about before. Given these constraints, this procedure is destined for a select few. Do you have anyone in mind now...?", Hinome explained as objectively as possible and finally asked for his opinion.

"I don't have anyone specific in mind at the moment; the war is approaching fast, and there is no time for performing it to anyone I might have. It is also best to keep these findings a secret for now within the clan. I feel like it is not the right time to be fully open just yet. Maybe in the future, when we are more powerful, but not now, just keep it hidden...",

"And as for us undergoing the procedure, I don't see it as the best move just yet. Remember the 'more powerful material' I mentioned before? It wouldn't make sense to proceed with just the basic enhanced cells we've developed when there's the potential for something much more impactful down the line...",

"After all, we still don't have any data on how a second procedure might affect someone who's already been through it once. We need to be careful...", Hikari responded thoughtfully. 

Hinome had successfully created a 'mini-bank' of chakra-engineered 'stem cells,' ready for transplantation into others.

The core benefit of these cells lay in their foundational attribute: they were a product of the physical energy component of chakra, synthesized through meticulous processes. Through the chakra pathway system, each cell was physically connected.

In this world, the principle was straightforward—the more cells one possessed, the larger the reservoir of chakra one could theoretically maintain.

This hypothesis was proven through the outcomes seen in the five 'test subjects,' although the increase in their chakra reserves was subtle enough to remain undetected by the clan at large.

This discretion was intentional, as the volume of cells transplanted was deliberately kept low to avoid drawing attention.

The advantage of these cultivated cells went beyond just an increase in quantity. Hinome, utilizing her expertise in Yang Release, had structurally enhanced these cells to perform 'more work.'

This meant that these cells contributed to a greater chakra pool and were inherently more efficient at generating and utilizing chakra than the ordinary cells found in most individuals. 

"Of course, I remember them. I'm actually quite excited to explore and experiment with that type of cellular material...", Hinome's expression brightened into a subtle smile, her curiosity evidently piqued by the materials Hikari had mentioned.

The cellular materials from the God of Shinobi himself, along with those from that distant clan that Hikari speculated might share an ancient genetic connection with the Hyuga, held vast experimental promise.

The prospect of integrating such extraordinary cellular material into their bodies was fascinating and tantalizing. Hinome mused over the potential abilities and enhancements that could emerge from such experiments.

The thought of what sparks of innovation and power they might unlock together fueled her scientific passion and deepened her resolve to push the boundaries of their research further.

"Well, I hope I won't disappoint you. That step is crucial for further enhancing our strength as Shinobi. For now, just concentrate on refining your microscopic vision, ensuring you can comfortably observe details at the DNA level and prepare to step into that area gradually as well. But, please take a break first, you've earned it...", He spoke, his tone softer than usual. 

As Hikari mulled over their conversation, a new consideration suddenly dawned on him, 'But now that I think about it, I'm still uncertain about having those cells injected into myself later. Should I successfully acquire them, or is it's better to wait until Hinome achieves proficiency with genetic-level body manipulation before opting for that procedure instead.',

'Injecting cells from Hashirama or the Kaguya clan, which I plan to secure somehow soon, raises questions. Specifically, could their introduction complicate my potential to achieve Tenseigan later through genetic manipulation due to the infusion of more diverse genetic material into my body? My understanding of these intricacies is virtually nonexistent...',

'If the material were from someone of Toneri's clan on the Moon, it might even be beneficial. But I'm uncertain about other cells...', He continued to ponder, 'Given the significant progress I've made with natural energy and the horizons that should be about to be unlocked there, I don't feel a pressing need for power enhancement for now.',

'I likely won't face any major obstacles to personal strength improvement in the coming years. However, for Hinome, gaining strength is absolutely critical right now. In a world that's becoming increasingly perilous, both within the walls of Konoha and beyond, ensuring she can defend herself is paramount.',

'She is, without a doubt, my most valuable ally. Currently, her combat capabilities are essentially at a Jonin level, which is objectively insufficient... And she would become the Elite Jonin after mastering that new combined nature release that she was slow in mastering in thanks to this research taking her time.', 

However, their contemplative silence was abruptly interrupted by the sound of hurried footsteps echoing through the residence.

Instinctively, they activated their Byakugan, scanning the approaching presence with precision. Recognizing the figure as one of Hikari's personal assistants, they deactivated their Byakugan and exchanged a knowing look before stepping outside to meet him.

The assistant, a young male from the side branch, stood at attention, offering a respectful salute: "Third Elder-sama, Hinome-sama, I apologize for my intrusion..." he began, catching his breath from the rush.

"However, an attendant has been sent from the Patriarch's Estate. It seems an urgent Elder Council meeting has been announced, and all Elders are summoned to attend right now...",

His words, delivered with a mix of urgency and deference, hinted at the gravity of the situation.

Both Hikari and Hinome turned serious as they understood the significance of such a summon; the Elder Council meeting declared on such short, even immediate notice certainly pertained to matters of the utmost fundamental importance and urgency for the entire clan.

"Don't worry, Hinome. If nothing out of the ordinary arose, then this is likely related to what we've been discussing recently. It seems that the Third Great Ninja War is on the verge of officially starting..." Hikari stated, his gaze shifting from Hinome to the attendant, hints of soberness and resolve in his eyes.

"Return to your residence for now. I'll call you as soon as I return from the meeting; we have something else to discuss then.",

With that said to the slightly worried Hinome, he nodded to both of them, signaling an end to the conversation that way.

Hikari then turned and walked towards the estate's exit, his steps carrying a sense of urgency that was uncharacteristic of his usual, more stoic kind of state and demeanor.

Unbeknownst to him, his fists were slightly clenched at his sides—a subtle indication of the emotions brewing within him. Whether it was excitement or apprehension that tightened his grip, the others did not see it. This small detail underscored the weight of the moment, reflecting the tension and uncertainty that came with the impending conflict.