In the vast compendium of poisons recorded by Sunagakure, there exists a particularly dangerous substance known to induce widespread cellular necrosis. While most would deem this poison too lethal to have any practical application in the field of medical ninjutsu or advanced genetic manipulation, for Senmei Asahi, it represented something more—a possibility.
The idea had been conceived long ago: using poison not to destroy, but to suppress. Specifically, to suppress the overwhelming vitality of the First Hokage's cells—the so-called "Hashirama cells." With those cells now in his possession, Asahi saw the time ripe to put theory into practice. His objective was clear: engineer a poison potent enough to inhibit the rampaging nature of the Hashirama cells, yet controlled enough to avoid causing fatal damage to the host.
This concept wasn't born out of idle curiosity. The fusion of Hashirama cells into one's body had always come with catastrophic risks. Those who survived the process, like Yamato, were exceedingly rare. Most ended up devoured from within. To prevent that fate, Asahi's proposition was deceptively simple—create a targeted cytotoxin. One that wouldn't kill, but would curb the cells' aggression long enough for the body to adapt.
However, therein lay a significant complication. Injecting a toxin strong enough to tame the Hashirama cells would invariably damage the body's natural cells. Without a way to neutralize or become immune to this cytotoxic effect, the experiment would end in death every time. Thus, Asahi's next priority became evident: crafting a vaccine that could make the body immune to the poison beforehand.
Early the next morning, Asahi headed to the archives in Konoha Hospital. After navigating through dusty scrolls and sealed cabinets, he found the antidote formula devised by Tsunade herself—the pinnacle of medical ninjutsu.
But his hopes were quickly dashed.
The antidote merely neutralized the poison. It didn't restore damaged tissue or revive necrotic cells. If the poison and antidote were administered simultaneously, their effects would cancel each other out. This stalemate yielded nothing of value. Worse yet, if ordinary cells were still being destroyed before the antidote could act, the whole point of the procedure was rendered moot. What was the use of fusing Hashirama cells into a corpse?
Asahi spent the day brooding over the limitations and eventually concluded a new path: reverse-engineer the antidote to synthesize a preventative vaccine. If he could create a compound that provided immunity—one that allowed the body's natural cells to withstand the poison while letting it suppress the Hashirama cells—then controlled fusion would be possible.
His research was divided into four major phases.
Step one: design and refine the cytotoxin. The goal was to identify a concoction that could suppress Hashirama cells without killing them outright. He dubbed it "Primary Suppression Cytotoxin".
Step two: develop an immune vaccine based on the cytotoxin, effectively inoculating the user against its effects.
Step three: introduce the Hashirama cells into the subject's body using Orochimaru's experimental method—one that had already yielded Yamato as a rare success.
Step four: once the Hashirama cells begin to activate, administer the cytotoxin. Its job: inhibit the cells just enough to prevent them from overwhelming the body, thus enabling a gradual, symbiotic fusion.
Orochimaru's previous sixty test subjects had mostly died. Only Yamato survived the process, and even he lacked the raw power of the original. Still, the experiment proved the process could work under the right conditions. Asahi would take that foundation and fortify it through pharmacological intervention.
Even under the most optimistic projections, he would likely reach Yamato's level—a stabilized host for the Shodai's cells, capable of wielding Wood-style techniques, if not with the same divine power of Senju Hashirama.
The theory, though elegant, had obstacles. Cells constantly divide and differentiate in the human body. While most tissues could repair damage through division, nerve cells could not. Furthermore, Hashirama cells were absurdly resilient. Even decades after removal from the host, they remained alive. Overpowering such regenerative potency required an extreme level of toxicity.
Back in his lab, Asahi wasted no time. Vials of extracted poisons from various shinobi regions were uncorked, synthesized, and rebalanced. The cytotoxin's concentration was steadily increased, new poisons were added for experimentation, and countless samples were subjected to stress tests.
The process was long, monotonous, and at times demoralizing. Yet Asahi persisted. He was a shinobi forged by war; patience was in his blood.
A month passed, and his injuries—remnants from his last frontline assignment—had healed entirely. He resumed daily training, and even returned to active duty, taking on two missions with Sarutobi Asuma and Yuhi Kurenai to hunt down missing-nin. These assignments, strategically chosen, offered minimal time drain while maintaining field credibility. Escort missions were too long and bureaucratic. Eliminating deserters? Swift and efficient.
Deserters from every village plagued the borders during wartime. Asahi had no respect for such cowards. In his mind, they weren't rebels—they were quitters.
Konoha, too, was showing signs of exhaustion. The long-drawn conflict had left even its veterans weary. Asahi suspected the upper brass was seeking a swift end to the war with Kumogakure. Every whisper he picked up pointed to looming peace talks—or, at the very least, strategic alliances.
That suspicion was confirmed in a discreet meeting with Shimura Danzo. The aged war hawk informed Asahi that Sarutobi Hiruzen intended to ally with Iwagakure to deliver a final blow to Kumogakure. The price for the alliance? Substantial.
Danzo presented this information with a venomous undertone, clearly attempting to pit Asahi against the Third Hokage. After all, Konoha had suffered immensely in its past battles with Iwagakure. Asahi himself had lost comrades in that conflict. To now offer an olive branch to the village that had slaughtered them felt like betrayal.
Still, Asahi was no fool.
'The dead are gone. But the living still bleed. If allying with Iwa shortens the war, then perhaps it's worth the price.'
He remained unmoved by Danzo's political manipulations. Power games among elders did not concern him—unless they became his problem.
As preparations for Konoha's final engagement against Kumogakure accelerated, Asahi threw himself fully into his cytotoxin development. Before heading to the battlefield again, he needed to present his findings to Orochimaru and barter for something valuable—perhaps forbidden jutsu, or data on test subjects. Something to elevate his own power.
He had once planned to cut ties with Orochimaru entirely. The Snake Sannin was dangerous, unstable, and destined for betrayal. But with Danzo offering a protective umbrella, the risks seemed… manageable.
'Risk brings profit', Asahi thought. 'And I've always bet on myself.'
Another two months passed.
His appointment to the front line finally arrived.
Around the same time, strange movements stirred the shinobi world. Uchiha Obito had awakened from his abyss, and the tides shifted rapidly. Kirigakure—formerly locked in battle with Kumogakure—unexpectedly signed a truce with their once-enemy and turned its blade toward Konoha.
The world was stunned.
Why would the Fourth Mizukage abandon hostilities with Kumogakure only to challenge Konoha? Many speculated about secret deals, unspoken favors, and promises of power. But Asahi wasn't surprised.
There was no justice in war—only interest.
And interest had now painted Konoha as the next target.
*****
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