You're a madman."
Looking at the frail test subject before him, Ryujin Kenichi scratched his head. He didn't take pleasure in this kind of work, but there was no other way. Only he possessed cancer cells, and if he wanted to develop the ninjutsu he envisioned, he had to resort to these experiments.
"Don't worry, I'm not here to gouge out your eyeballs today," Kenichi muttered, watching the subject's bloodshot eyes twitch.
So far, he had confirmed that Yang Release chakra did indeed stimulate the accelerated growth of cancer cells. However, the lack of a sterile environment in this makeshift lab prevented cancer cells from surviving outside a living host for long. That meant he had to conduct live experiments, injecting Yang Release chakra directly into the subject's body to see how the cells reacted.
Kenichi tapped his chin, thinking aloud. "First, I need to infuse the Yang chakra properly. Then, I need a way to rapidly identify and track the cancer cells..."
He pulled out a scroll and began taking notes. Before he could create a medical ninjutsu that utilized cancer cells, he first had to overcome the difficulty of transmitting his own chakra into another's body in a controlled manner. His progress had been slow, even with the benefits of Hashirama Senju's potent physique. The sheer vitality of his body made Yang Release manipulation easier, but precise infusion was another challenge altogether.
Even if he solved that, there remained an even more pressing issue—how to make Yang chakra act exclusively on cancer cells? Normally, cancer cells were scattered throughout the body in minuscule amounts, eliminated before they could develop into anything malignant. In contrast, his test subject had cancer cells concentrated in a fixed area, making the experiments somewhat manageable. But what if the next subject didn't have any cancer cells at all?
"This is too troublesome..." Kenichi groaned, rubbing his temples. "I might as well create a cancer cell directly in the subject's body. If I control its growth, I can limit the damage."
Realizing he had been overcomplicating things, Kenichi's expression brightened. Instead of painstakingly searching for cancer cells, why not simply generate them? His chakra control was precise enough, and a well-placed application of Yin-Yang Release could manipulate the very foundation of life. After all, wasn't Hashirama's Wood Release capable of forming living tissue from chakra alone? If his medical theories were correct, then targeted mutation wasn't beyond his reach.
Kenichi turned toward his restrained test subject. The man's cancer was primarily in his brain—too risky for now. Instead, the lungs seemed like a better option.
"The lungs are vital," he mused. "Disrupting them will produce immediate, observable symptoms."
Cancer cells emerged when DNA damage forced a normal cell into uncontrolled growth. Carcinogens like tobacco were known to trigger this process. Kenichi smirked and reached into his pocket, pulling out a cigarette.
"Want a smoke?" he offered casually.
The subject said nothing, only staring at him in horror.
Kenichi chuckled. "No? That's fine. The nicotine is all I need."
Dissolving shredded tobacco in high-purity alcohol, he extracted the nicotine using basic separation techniques. Then, molding his chakra into delicate tendrils, he guided the extracted substance into a chakra-infused solution, testing its reactivity with his Yang Release.
"If this works," he whispered, watching the mixture glow faintly under his chakra's influence, "then cancer itself will become my greatest weapon."
He turned back to his test subject, his fingers crackling with energy.
"Let's begin."
Ryujin Kenichi let out a slow sigh, his fingers tapping against the side of a glass vial. "It's a pity nicotine cannot be crystallized. It would be far more convenient that way."
He swirled the solution inside the vial, watching the pale amber liquid catch the dim light of the underground laboratory. While nicotine could be frozen in a liquid state, there was no need for that. Instead, he had prepared it in a refined solution, neatly loaded into a compact spray device. With practiced ease, he aimed it at the chest of his test subject and pressed the trigger.
The man flinched, his pale eyes narrowing as the cool mist coated his skin. "What are you doing?" There was a tremor in his voice, his body tensed in alarm. As a member of the Hyūga clan—albeit an illegitimate one—he was trained to suppress fear, but the unknown was always unsettling.
"No need to be so nervous," Kenichi replied calmly, watching as the liquid began to absorb through the skin. "Nicotine can enter the bloodstream transdermally. If injected directly into a vein, it acts as a potent toxin."
The Hyūga clenched his jaw but remained silent. He knew struggling was pointless.
Kenichi continued his explanation as he scribbled notes on a worn scroll. "It's classified as a neurotoxin, which means medical ninjutsu like Fine Hand Manipulation can extract it. But without a skilled medic-nin nearby, the victim would be forced to endure the effects." His mind whirred with possibilities. "Perhaps it could be weaponized. Cigarettes are common in the ninja world, after all. One could lace them with a more potent dose..."
He paused, tapping his pen against the scroll. "Still, there's an issue. Shinobi have superior physical conditioning compared to civilians. The lethal dose for a normal person might not be enough for someone with enhanced chakra reserves. More experimentation is necessary."
Kenichi turned his attention back to the Hyūga in front of him. His breathing was still steady—too steady. Adjustments would be needed. Precision was key; if the nicotine bypassed the lungs too quickly, its effects would dull before reaching the desired intensity.
"You're going to need more stamina for this," Kenichi mused, setting down his notes. He reached for a small tray with a nutrient-rich ration pill, the same kind ANBU operatives used to sustain themselves on long missions. "Eat. It'd be troublesome if you died too soon."
The Hyūga hesitated before reluctantly obeying, his pale fingers trembling slightly as he picked up the pill and swallowed. He understood his fate was sealed the moment he was taken here, deep within Orochimaru's hidden laboratory.
Just as Kenichi was preparing his next test, the sound of footsteps echoed through the stone corridor. He turned just as a familiar serpentine figure entered the room.
Orochimaru's golden eyes flickered over the scene, his lips curving into a smirk. "What have you done to this one?" His tone was amused, though there was an undercurrent of curiosity.
Kenichi chuckled, rubbing the back of his neck. "Just a few experiments. I wanted to understand the origins of his unique cellular composition."
Orochimaru stepped closer, his gaze sweeping over the near-unconscious Hyūga. "You've been busy."
"You were gone for eight days," Kenichi pointed out. "I made good use of the time."
The Hyūga, once capable of cursing Kenichi through gritted teeth, now lay limp against his restraints, his body utterly exhausted. Yet the research had been fruitful—Kenichi had made progress. Not only in understanding the effects of neurotoxins on chakra-enhanced physiology, but also in his ability to inject Yang-release chakra directly into the lungs. The applications could be groundbreaking.
Orochimaru's smirk deepened. "Fascinating. Perhaps your work is progressing even faster than I expected."
Kenichi met his gaze and smiled. "Of course. I wouldn't want to disappoint you, Sensei."
The laboratory was silent for a moment, save for the rhythmic drip of water from the ceiling. Kenichi knew his work was far from over. There was still much to refine, many more experiments to conduct. But he was on the right path.
And in Orochimaru's world, progress was everything.