CHAPTER 25

While a massive influx of Yang-attribute chakra could previously induce respiratory alkalosis, the effect was too obvious, and the success rate was low—it wasn't subtle enough for true efficiency.

Now, after refining his technique, Ryujin Kenichi had devised a way to diffuse Yang-attribute chakra into the air around him. This allowed it to subtly accelerate cell division in those who inhaled it, worsening pre-existing cancerous conditions or even inducing new malignancies.

Theoretically, Kenichi believed that with further refinement, his technique could evolve into a deadly, wide-range ninjutsu—one that would silently weaken enemies over time, making them vulnerable before they even realized what was happening.

For now, however, he had no urgent need to use it as a weapon. He was more interested in testing its effects on a live subject—specifically, a Chunin captured for experimentation.

"Teacher, look here. The lungs of this test subject have already begun showing early-stage cancerous lesions," Kenichi said excitedly to Orochimaru. His hypothesis was proving correct. Even a trained Chunin, whose body had been tempered by years of combat, was not immune.

No one was.

As long as a person needed to breathe, they couldn't escape the influence of cellular decay.

Early-stage cancer might not significantly impact combat ability, but what about later stages? What about terminal illness?

Kenichi had visited hospitals before, back in his previous life. He had seen cancer patients suffering—reduced to frail, tormented shells of their former selves. They could barely move. Even lying down was agony. The constant pain was inescapable.

If his experiment succeeded, he could impose that same fate on his enemies. Slowly, inevitably, their bodies would break down. Even skilled shinobi, no matter how resilient, would deteriorate over time.

"I see in your report that the Fine Extraction Technique has no effect on this condition?" Orochimaru asked, scrutinizing the test subject's afflicted lung before glancing at the uninfected one with curiosity.

"Yes, sensei. Cancer cells originate from the body itself. The Fine Extraction Technique identifies and removes foreign contaminants, but it cannot distinguish cancerous cells from healthy ones. They are part of the host, not an intrusion."

Kenichi had already tested this theory with medical ninjutsu specialists. They had attempted to cure patients suffering from similar conditions, but their efforts yielded limited success. Only early-stage cases showed any potential for recovery, and even then, outcomes varied based on the individual's constitution.

No known medical technique had ever cured a case of late-stage cancer, let alone terminal illness. Of course, this might be due to the ninja world's still-limited understanding of cancer.

"Continue. I want to see the effects of later stages," Orochimaru instructed, his anticipation evident. There were similarities here to Hashirama's cells—an abnormality in natural regeneration and cellular growth.

Kenichi nodded. He understood the implications. However, if the experiment progressed too far, the subject would soon become unsalvageable.

As he continued infusing Yang-attribute chakra into the test subject's lungs, changes became increasingly visible. White, irregular masses began forming—tumorous growths large enough to be seen with the naked eye. They spread, consuming healthy tissue, leaving concave indentations in the lung's surface.

This was the direct manifestation of aggressive lung cancer.

"It takes too long," Orochimaru observed critically. "Kenichi, you need to refine the process."

He nodded in understanding. On a battlefield, there would be no time to stand around and infuse chakra for extended periods. The technique's limitations were significant—it wasn't viable for immediate combat but had clear potential for long-term assassination.

Orochimaru seemed to share his thoughts. "For example, my old sensei, Hiruzen Sarutobi, who loves his tobacco... If you refine this properly, you could make it seem as though a heavy smoker simply succumbed to an inevitable fate."

Kenichi scratched his head, thoughtful. His technique still needed further development, but if perfected, it could have devastating applications.

But his research didn't have to stop at lung cancer.

Nicotine accelerated lung cancer growth, but what about other tissues? Searching for specific carcinogens for every organ would be tedious and inefficient.

Then an idea struck him—one inspired by knowledge from his past life.

Radiation.

When radiation was first discovered, it was hailed as a miracle. Some even made cosmetics infused with radium. It wasn't until later that people realized its true effects—that radiation could destroy cells, cause mutations, and induce cancer.

If he could identify sources of radiation within the ninja world… If he could harness them…

Then, Kenichi thought with a grin, he wouldn't just be accelerating cancer.

He could create it.

After Orochimaru had assessed the progress of the current experiment, he decided to leave. Before departing, he instructed Ryujin Kenichi to record the time a certain Chūnin could survive, as well as document any symptoms that arose during the process.

Ryujin Kenichi didn't need to be told twice. Even if his teacher hadn't specifically mentioned it, he would have done it anyway. After all, this was a rare and valuable Chūnin specimen, one that wouldn't come around often.

Once the experiment was concluded, Kenichi went to grab something to eat—ramen, to be exact. This time, he headed to Ichiraku Ramen.

Ichiraku Ramen had been a staple in Konoha for many years, having witnessed the growth of many ninjas. When Nohara Rin was still alive, she, along with Obito and Kakashi, often visited this very ramen shop.

Kenichi made the occasional trip to Ichiraku, as the ramen here was undeniably delicious, though it was more expensive than the place he usually frequented. In fact, he often thought the ramen at his regular spot was cheaper simply because it didn't taste as good as the food at Ichiraku.

Just as Kenichi was settling in and taking his first bite, he noticed someone sitting just a couple of seats away from him. The unmistakable spiky hair was enough to immediately identify the person—Kakashi Hatake.

Kenichi glanced at Kakashi, who appeared just as he always did: aloof and quiet, though Kenichi noticed he seemed to vanish and reappear in strange places more often than usual. He suspected Kakashi had joined Anbu, given the way he moved now. The Fourth Hokage, Namikaze Minato, had hoped that the high-pressure tasks of the Anbu would help Kakashi recover from his emotional trauma. From the results later, it seemed to have worked, at least somewhat.

"Kamui..." Kenichi murmured under his breath. The more he thought about it, the more he felt that the space-time jutsu would be perfect for him. However, Kamui was currently possessed by two people: Kakashi and Obito.

Kakashi was relatively easy to approach, but Obito? Not so much.

Moreover, the full version of Kamui, as wielded by both of them, was far more powerful. Kenichi found himself wondering what had happened when Obito was caught in the Kamui dimension. Surely, Kakashi must have bombarded him with explosive tags and kunai, right? It made Kenichi feel a bit sorry for Obito. Despite all his bitterness, he had truly cared for Kakashi, even going so far as to leave his own eye behind.

Kenichi couldn't help but shake his head at the thought. Despite the tragic circumstances, Obito's love for Kakashi was undeniable.

Kakashi, as usual, remained expressionless, showing no signs of acknowledging Kenichi's presence. Kenichi had no interest in forcing a conversation with someone who seemed so intent on remaining aloof, so he focused on finishing his meal.

By the time he had finished eating, Kakashi had already left, without so much as a glance in Kenichi's direction.

Kenichi wasn't bothered. He simply picked his teeth with a toothpick, paid for his meal, and leisurely began walking home.

Just as he had taken a few steps, however, a voice he found particularly annoying rang out.

"Senior Ryujin!"

It was Anko Mitarashi. Kenichi sighed internally. This was going to be another one of those days.