Ten minutes later.
Orochimaru stared at the blood sample in the test tube, now the color of cola, lost in thought.
To be precise, it wasn't just the dark, fizzy hue.
The "cola" was bubbling—tiny pockets of air forming, merging, and bursting. The glass tube, sturdy as it was, started showing fine white cracks, as if it might shatter any second.
"Is this… what flows through Miss Eri's veins all the time?" Orochimaru asked.
"Yup, that's how hybrid blood works," Hikari Uchiha nodded. "Mix it with normal human blood, and you'll get a nasty explosion. It creates a highly corrosive compound that can burn through a carpet in seconds."
"?"
Orochimaru blinked, momentarily thrown, but he'd seen enough weird stuff to recover quickly. He got to work, methodically analyzing the sample.
Hikari took a vial of serum from Eri and handed it to Orochimaru, along with research notes from Herzog. "This serum was extracted from a hybrid fetus with even worse erosion. It suppresses the damage but mainly pushes bloodline evolution…"
Exactly.
The serum was essentially an evolution drug.
Herzog's goal was to use Eri as a vessel for the "Holy Skeleton," filtering out its toxins so he could ascend as the White King. To do that, he needed Eri alive until the Skeleton emerged, while also pushing her bloodline closer to the White King's to make her a better container.
The serum was a double-edged sword—quenching thirst with poison. Without the "Holy Skeleton," Eri's bloodline would spiral out of control eventually. It was just a matter of time.
Since Hikari had decided to let Orochimaru tackle this research, she took a moment to explain it in detail.
"…Hybrids, Deadpool, Dragons?" Orochimaru narrowed his eyes. "Do these things really exist in the ninja world?"
"Think of it as a far-off continent," Hikari said.
"…Alright." Orochimaru gave Eri a long look but didn't press further. He turned back to his lab bench. "I'll need a few days to analyze this. Miss Eri might need to cooperate with some tests. If you're worried, Lady Hikari, you can stick around to watch or roam the base as you like. Just tell Guren and the others if you need anything."
"Cool."
Starting the next day, Hikari split off a few shadow clones. One handled daily training, another went searching for Jugo, a third gave Karin some pre-training prep, and another grilled Guren and the others for intel on the Sound Village's current state. Oh, and she made sure to place a Seal on everyone, just in case.
Her real body stayed in the cave, keeping an eye on Eri during her tests. She answered Orochimaru's questions and helped with some of Eri's physical exams.
In her spare time, she browsed Orochimaru's book collection.
Gotta say, Orochimaru's knowledge stash was impressive.
Unlike the power-obsessed meatheads in the Uchiha clan, he was on another level.
Heck, the whole ninja world leaned that way. The "Ninjutsu Doctor," Hiruzen Sarutobi, knew a ton about ninjutsu but probably hadn't cracked open many science books. Meanwhile, the rough-and-tumble Cloud Village quietly leapfrogged everyone, building a chakra cannon that could blast the moon just a few years after the Fourth Great Ninja War…
In Orochimaru's cave, Hikari found shelves packed with books on anatomy, pharmacology, pathology, and even psychology. There were some math and physics texts too, though fewer, and those fields seemed less developed than the medical ones.
"…You can read these, Lady Hikari?" one of Orochimaru's shadow clones asked, peering over her shoulder after watching her for a bit.
"What do you think?" Hikari shot him a sideways glance.
In her past life, she'd been a science major with decent grades. She wouldn't claim to master these technical books on the first read, but she could grasp the gist. With enough time and focus, she could probably get a solid handle on most of it.
After a moment's thought, Hikari dug through her universal capsule and pulled out a stack of books, setting them on the table. "Here, take a look."
Orochimaru, puzzled, picked one up and scanned the titles—
Euclid's Elements, Number Theory, Calculus, Linear Algebra…
Yup, most of these were bought in the Dragon world.
A few others were tossed her way by Dr. Brief last time she visited.
Orochimaru flipped through them casually at first, but his eyes soon sharpened. "Lady Hikari, did these come from that 'friend' of yours from another continent?"
"Something like that."
"…Got any more?"
"Want them?" Hikari's lips curled into a half-smirk, her tone playful. "How about a trade for the Ryuchi Cave scroll?"
Orochimaru froze, narrowing his eyes. "Are you serious, Lady Hikari?"
"Dead serious."
The Ryuchi Cave scroll was one of her main goals for this trip.
Summoning beasts were secondary. She really wanted to study the Sage Mode of the three holy grounds and figure out what kind of power it was.
Though, trading a few math books for the Ryuchi Cave scroll might be a bit uneven…
"How about this," Hikari continued. "I mentioned those 'demons' earlier—I can give you a few live samples. Plus, some Uchiha blood samples. That should be fair for your summoning scroll, right?"
Orochimaru smiled. "Since you're so keen, Lady Hikari, I'll do my best as your subordinate… But fair warning: the Ryuchi Cave snakes I've contracted with are a prickly bunch. Even I have to pay a steep price to summon them."
"No worries," Hikari grinned brightly. "I love dealing with rebellious kids."
Speaking of which…
"The Sage Mode of the three holy grounds is all about harnessing natural energy, but there's a risk of being consumed by it. In the Dragon world, dragons control elements through their blood, which can also erode humans… Don't you think there's some overlap there?"
The thought hit Hikari out of nowhere.
"You've considered it too, Lady Hikari?" Orochimaru's raspy voice replied. "When you mentioned the hybrid origins, I had a similar hunch. But since I don't know much about Sage Mode, I didn't want to jump to conclusions.
If you're curious, you could visit Ryuchi Cave yourself and ask the White Snake Sage. You might get some answers."