For Uchiha Shinji, Orochimaru's secret base was a treasure trove.
Many of the books and materials inside were rare, one-of-a-kind in the shinobi world, obtained by Orochimaru through brutal and bloody human experiments.
Others, even if they had the means, might not match Orochimaru's wild imagination or iron-hearted resolve.
Among all the researchers and medical shinobi studying the human body in the shinobi world, Orochimaru might not be the most gifted, but he was undoubtedly the most flexible with his ethics and the most relentless in action.
Casually flipping through a few books on the shelf, Shinji felt as if he'd struck gold.
If Orochimaru weren't standing nearby, he would've grabbed a stool and devoured every blood-tinged book and document in the room.
Soon, Shinji and Orochimaru began discussing treatment plans.
More precisely, Orochimaru proposed several plans he'd devised, using them to probe Shinji's true intentions.
Shinji didn't play games with Orochimaru. He outright rejected the proposed plans, saying, "Your approaches only treat the symptoms, not the root cause. From the data, Kimimaro's Bloodline illness isn't so much a disease as it is his body's inability to withstand the erosion of his Shikotsumyaku."
"Exactly," Orochimaru nodded, having reached the same conclusion.
Shinji continued, "So, to fully resolve this Bloodline illness, there are only two paths: either remove Kimimaro's Bloodline Limit or fundamentally enhance his physique."
Orochimaru fell into thought.
Seeing no objection, Shinji got to the point. "Removing the Shikotsumyaku would be like killing his talent—it's no different from killing him. So our only option is to strengthen his physique to resist the Shikotsumyaku's corrosion."
Orochimaru shook his head. "Kimimaro's physique is already among the best in the shinobi world. Most methods to enhance a physique would be ineffective on him."
Shinji smiled. "That's why we need to design a biological armor!"
Orochimaru's gaze sharpened.
He caught two key pieces of information in Shinji's words: the concept of biological armor and the use of "we."
Clearly, this powerful 'A' needed something from him!
Ignoring Orochimaru's scheming, Shinji laid out his design concept.
Orochimaru initially listened halfheartedly, but as time passed, his eyes gleamed brighter, a sense of "Can it really be done like this?" stirring within him.
Thus, Orochimaru set aside his ulterior motives and began seriously evaluating the feasibility of Shinji's idea.
After some verification, he was invigorated. "It's worth a try!"
"Of course it is!" Shinji quipped inwardly, knowing his idea was adapted from Madara Uchiha's method for creating specialized White Zetsu.
As if struck by a thought, Orochimaru smirked. "Cellular tissues capable of significantly improving Kimimaro's physique are rare in the shinobi world. Whose are you planning to use?"
Shinji grinned. "The strongest, naturally!"
After Shinji left, Kabuto emerged from the shadows, reporting, "Lord Orochimaru, no suspicious individuals were detected nearby. 'A' likely came alone this time."
Orochimaru smiled. "No need to worry. I've figured out what he's after!"
Kabuto's curiosity piqued. "Oh? What did you discover?"
"Yakumo Kurama!" Orochimaru said with a laugh, naming a person.
Kabuto caught on immediately. "So, the Akatsuki wants to use you to master the First Hokage's cell transplantation technique?"
Orochimaru was confident. "Though 'A' tried to hide his true intentions, he can't fool me. Treating Kimimaro is just a pretext—what he really wants is the First Hokage's cell transplantation technique!"
Meanwhile.
On his way back to the village, Shinji thought, "Let Orochimaru wrestle with using the First Hokage's cells to create the biological armor. All I need is his equipment and expertise!"
He'd suggested using the First Hokage's cells purely to avoid handing over his own cellular tissue to Orochimaru.
Unbeknownst to him, Orochimaru had mistaken this for his true objective.
In the days that followed, Shinji kept a close eye on the Ōtsutsuki branch family's movements on the moon while collaborating with Orochimaru on the biological armor research.
The dominance of the First Hokage's cells was undeniable.
When Madara created White Zetsu, he had to use the Divine Tree's power within the Gedo Statue to dilute the cells' intensity.
Otherwise, stable White Zetsu couldn't have been produced.
Shinji and Orochimaru faced the same issue Madara did when using the First Hokage's cells for the biological armor. Once activated, the cells couldn't be shaped or maintained in a stable state.
If used to create biological armor, it would erode the host's body, proliferating uncontrollably like a tumor.
After several failures, Shinji deliberately suggested trying other cellular tissues.
Orochimaru was open-minded in biological experiments, willing to test any viable method, so he agreed to Shinji's proposal.
However, he remained fixated on the First Hokage's cells, believing that using them for biological armor was safer for the host than direct implantation.
Shinji, meanwhile, gathered a variety of cellular tissues and used Orochimaru's lab for repeated experiments.
Through constant trials, he learned and refined his concept.
Seizing a moment when Orochimaru was absent from the lab, he took out his own cellular tissue and began crafting his biological exoskeleton.
Using the lab's large-scale cell culture dishes, expensive nutrient solutions, and instruments for observing cellular fusion, he created a biological exoskeleton with White Zetsu's cellular tissue as the framework and his own as the core.
The biological exoskeleton was palm-sized, spherical, and closely resembled White Zetsu's tissue in appearance, though its hue leaned toward silvery-white.
At this stage, Shinji remained cautious. Following his pre-planned approach, he began inscribing sealing jutsu formulas into the biological exoskeleton, ensuring the White Zetsu cells within wouldn't run rampant.