An ordinary demon cannot infect another person; only the Demon King can turn a human into a demon.
For Orochimaru, however, this was not an issue. As a top-tier scientist, it only took him a short time to overcome this problem.
Just as Tamayo had taken several hundred years to succeed with a single case, the ninja world's number one genius scientist, Orochimaru, cracked the problem in just two months. The blood from the world of Demon Slayer was hardly a challenge for him.
He directly extracted blood from the test subject Uchiha Nagi had provided, cloned it, and then ran continuous experiments on a few unfortunate captured bandits.
Orochimaru's cloning technology was second to none in the ninja world. While others could clone humans and animals, he could not only clone people but could even clone the horn right off a Tailed Beast's head.
It made one wonder if, given enough time, he could clone an entire Tailed Beast for you to see.
But with this success came another problem. This "perfect" creation was not perfect at all. It could only appear at night. The moment it was exposed to sunlight, it would turn to ash, as if the sun were a potent poison.
Orochimaru tried various methods, but nothing worked. The subject was afraid of any ultraviolet light similar to sunlight, but those rays only harmed it; they couldn't kill it. Sunlight, however, was the deadliest of poisons. Exposure was certain death. There was no solution.
This realization completely chilled the part of Orochimaru that had been eager to take over its body. What was the use of a vessel that couldn't appear in the sunlight? Even if this vessel could grant him eternal life, the price was to forever hide in the dark sewers, never to see the light of day.
This was undeniably imperfect. Orochimaru was a man who pursued perfection. The fact that after capturing Sasuke, he placed no restrictions on him, instead unreservedly developing his body and allowing him to grow, planning to take him over only when he was at his strongest—this showed just how much Orochimaru valued perfection.
Otherwise, with Shin's cells and the First Hokage's cells in his possession, and likely a few pairs of Sharingan in storage, he could have easily modified his own body just as he had for Danzo.
But this half-finished product that couldn't exist in the sun? Orochimaru would certainly never choose it as his own vessel.
"Aaaah... ah..."
The test subject, tortured by Orochimaru into a mindless state, finally found release under the sunlight, turning into a puff of ash.
"Lord Orochimaru, this..."
"It's no loss. A creature that cannot exist in the sunlight is ultimately just an incomplete product."
Orochimaru watched with a hint of regret. Such a perfect specimen, with no physical weaknesses or vital points, yet it was inexplicably afraid of the sun.
Orochimaru and Kabuto stood in the shade, quietly watching as the test subject was incinerated by the sunlight, its ashes slowly scattering in the wind.
"Kabuto," Orochimaru said suddenly, "I have a mission for you. Infiltrate Konoha and prepare for the plan four years from now."
Kabuto adjusted his glasses and nodded. "Yes, Lord Orochimaru. I will prepare and head to Konoha at once. Are you planning to continue your search for a vessel?"
How to infiltrate Konoha? It was laughably simple. They had an inside man: Danzo. Danzo and Orochimaru had been colluding all along. Later on, Danzo would even send Sai to maintain contact with him.
"I need to find the person who gave me this test subject." Orochimaru licked his lips. "The hope is slim, but he might have some clue as to how to solve this specimen's defect. After all, Sasuke is still too young."
Kabuto asked, "Uchiha Nagi?"
Orochimaru nodded. "Mm, he was the one who gave me this material for eternal life."
Uchiha Nagi. Kabuto adjusted his glasses again, committing the name to memory. While the material's weakness to daylight was a major flaw, at night, it was...
Back in the Land of Iron, Uchiha Nagi went on a spending spree, lavishly buying all sorts of equipment and precision instruments he couldn't afford before.
The technology tree of the ninja world was incredibly bizarre. There were trains (Land of Snow), personal flight devices, and a flying castle (Sky Ninja Arc), as well as chakra-powered robots.
There was also cloning technology, movie theaters, televisions, and chakra-powered walkie-talkies.
In the medical field, there were microscopes, blood transfusions, and various analyzers. In short, a whole lot of things that Kishimoto clearly never thought about how to explain.
High-end equipment was, in a word, a money sink. The ninja world was not yet an industrialized society. No machines were mass-produced, and the price of high-end, custom-made machinery was, as one could imagine, astronomical.
His five hundred million ryo seemed like a lot, but in reality, it wasn't even enough to buy half the equipment in a single Konoha hospital.
"Scientific research really burns through money. No wonder Orochimaru set up the Sound Village and colluded with Danzo. He was probably getting funds from Danzo all the time, maybe even selling him his research. Otherwise, the entire Sound Village wouldn't have been enough to cover his expenses."
Uchiha Nagi also remembered that Orochimaru loved setting up spare bases everywhere.
Spare bases...
The entire ninja world was covered by the eyes and ears of the king of paparazzi, White Zetsu. To escape its surveillance, there were only a few places.
Uchiha Nagi thought carefully. The moon? That was a good place, but which lake was the entrance? He had no idea where the space-time gate to the moon was hidden. Plus, the giant Tenseigan up there was a nuclear weapon; he wasn't confident he could win against it.
A second base was the flying castle. During the Great Ninja War, there was a Sky Ninja Village that had a hidden base capable of flying. He didn't know if the Sky Ninja had finished repairing it yet. Besides, the energy required to lift a flying aircraft carrier into the sky would be massive. The Sky Ninja Village had apparently created an artificial Tailed Beast, the Zero-Tails. That thing could be used as a power source for the flying fortress.
Besides those, there were two other locations. One was overseas. White Zetsu's surveillance of the various overseas islands was at its lowest. The other was the Land of Lightning's Turtle Island, a mobile base that floated on the ocean.
"It's decided. I'll just steal the Sky Ninja's flying fortress."
At the same time, there was another place that had a beast capable of powering it.
Naruto encountered it when he went to Turtle Island to train. It was an unnamed island rich in natural energy, which had given birth to many natural summoning animals.
After the Land of Lightning discovered the island, they set up a laboratory there, hoping to create the ultimate summoning beast through breeding and modification. The experiment went out of control.
Everyone on the island was wiped out, leaving only Uzumaki Honoka, who sealed the ultimate summoning beast with her own life.
Uchiha Nagi wouldn't seal such a creature inside himself as a battery, but throwing it into the Sky Ninja's fortress as a power source was an excellent idea. Plus, the island had many other powerful summoning animals.
"Uzumaki Honoka..."
In the Land of Grass, there was also Uzumaki Karin. It seemed she was taken by Orochimaru after participating in the Chunin Exams. When he had time, he would go look for her as well.
Uzumaki Honoka was a genius of sealing jutsu. At a young age, she was able to seal an ultimate summoning beast as powerful as a Tailed Beast. It would be a waste not to recruit her as a subordinate.
"This is getting complicated. There are too many things to do, and I can't be everywhere at once. And Kimimaro is still too young..." Uchiha Nagi sighed. He would have to take it one step at a time.
He had to conduct research, train, and find a lair for his base. His offer to join the Akatsuki was just him being polite to Kakuzu. He'd rather be the head of a chicken than the tail of an ox.
He'd have to be an idiot to go work as Pain's subordinate.
However, he could probably move his research to the world of Demon Slayer. The Ubuyashiki family there could provide him with a large amount of funding and raw materials. Besides, much of the technology there was already comparable to that of World War I; he could use it as a substitute.
"Hm, Sensei, you're back."
In the courtyard, Kimimaro, who had been practicing with his Shikotsumyaku, saw Uchiha Nagi and ran over happily. He also looked a bit sheepish, because he had been secretly developing his Shikotsumyaku behind his teacher's back, even though Nagi had repeatedly told him to use it less.
"Kimimaro, it's not that I don't want you to use your Shikotsumyaku. It's that your body may carry a hidden kekkei genkai illness. This kind of disease is genetic and has no cure. So, before you reach adulthood, you must control yourself and use its power as little as possible," Uchiha Nagi explained.
"I understand, Sensei. I will work hard on my Water Breathing. I will use the power of the Shikotsumyaku as little as possible," Kimimaro nodded.
Sigh.
Uchiha Nagi sighed internally. Kimimaro was a good student, obedient and respectful, but he was desperate to be helpful. That's why he trained so hard. However, the normal pace of training in ninjutsu and Breathing Styles was too slow for him, so he secretly practiced with his Shikotsumyaku.
Oh well. As long as I keep him out of high-intensity battles, living to sixteen shouldn't be a problem. In a few years, when Orochimaru attacks Konoha, I'll go steal a pair of Byakugan for him.
"Alright. You and Yukihime continue your training. I have something to do tonight, so I'll be going out."
"Sensei, are you going out to earn money again?"
Uchiha Nagi shook his head and smiled. "I already have the money. It's enough to last for a while. Tonight, I'm going to challenge Mifune and integrate my swordsmanship. It's something I can't do fighting anyone else."
Because everyone else mostly combined taijutsu and ninjutsu. Guy used taijutsu, not swordsmanship. Only by fighting a fellow swordsman like Mifune could he truly improve his own skills.
Uchiha Nagi looked up at the moon. "Mifune..."
"Hm?! A challenge letter?"
In the capital of the Land of Iron, besides the daimyo, lived the country's most powerful swordsman, Mifune. His status in the Land of Iron was comparable to that of a Kage in a hidden village. He was worshipped and respected by all the samurai in the country.
However, it was rare for anyone to issue him a challenge. Few samurai could defeat Mifune, and ninja didn't compete with him in swordsmanship.