While Shimizu was still lost in that strange line of thought, the little boy suddenly darted away, disappearing deeper into the dark, labyrinthine depths of the underground facility in the blink of an eye.
Just how vast was Orochimaru's laboratory?
Shimizu wasn't worried about the child running into danger. After all, this place was the boy's "home"—he was clearly familiar with it.
After that brief interruption, Shimizu quickly returned to the main laboratory where Orochimaru was working.
If he kept wandering around and accidentally ran into the Two-Tails' jinchūriki, it would only complicate things further.
"Did you see the Two-Tails' jinchūriki, Uzuki-kun?" Orochimaru asked without looking up.
"No…"
Orochimaru didn't press the matter and simply continued focusing on refining the Hero Water.
Even if Orochimaru didn't ask, Shimizu's curiosity lingered. Just what exactly was that child?
Calling him Orochimaru's illegitimate son had mostly been a joke.
But judging from Orochimaru's usual methods… there was a high chance the boy was either a rare talent with a powerful Kekkei Genkai—something like Kimimaro—or perhaps an unnatural creation born within this very laboratory.
"How much longer will it take?" Shimizu asked.
"In a hurry, Uzuki-kun?" Orochimaru replied calmly, not even lifting his head.
A little.
After all, secretly meeting with Orochimaru like this…
The shorter the time, the lower the risk.
Though, given Shimizu's abilities, the chances of the Anbu noticing anything were extremely slim.
"…I'm just a bit bored."
"Then I ask for your patience."
After a brief pause, Shimizu spoke again. "Oh right, Orochimaru, did you adopt that child?"
"You mean—have you met Erugetsu?"
"So his name is Erugetsu," Shimizu said, immediately realizing that was the boy's name. "He looks about two or three?"
"Not quite three yet."
"He said he was born here… don't tell me he's actually your son?" Shimizu joked.
Both Orochimaru and the boy shared that slightly unhealthy pale complexion, along with those narrow, calculating eyes often seen in classic villains. Because of that, the child carried a faint resemblance to him.
"Heh… you jest, Uzuki-kun." Orochimaru continued working as he spoke casually. "Erugetsu is a war orphan with nowhere to go. I simply brought him back to Konoha."
Bringing back a child who couldn't even mold chakra?
Since when had Orochimaru taken up charity work?
To Shimizu, the explanation sounded like an obvious cover story. But to Konoha's higher-ups, it was probably nothing more than a trivial act of kindness from one of the legendary Sannin.
Otherwise, how could that child be living safely within Konoha?
Since Orochimaru clearly had no intention of elaborating, Shimizu didn't bother digging deeper. "Didn't expect you to have a compassionate side."
"I merely felt something, seeing such a fragile life at the time," Orochimaru replied with a faint smile. "A momentary whim, nothing more."
As they chatted idly, time passed quickly.
Before long, Orochimaru completed the refinement of the Hero Water.
"This is the improved version," he said, handing Shimizu a small cup filled with a colorless, transparent liquid. "Just drink it."
With that, Orochimaru downed his own portion in one go.
No longer hesitating, Shimizu followed suit and drank it as well.
Instantly, chakra surged within his body, churning violently as it expanded at an astonishing rate. In mere moments, his chakra reserves surpassed twice their original level… then tripled.
"This phase will last for several minutes. Once it peaks, the chakra will gradually decline," Orochimaru explained.
"Afterward, your chakra reserves will continue to increase over time. Based on my previous experiments, this period may last anywhere from a few days to several months."
"The final effect varies depending on the individual's constitution."
With Orochimaru's detailed explanation, Shimizu finally understood the full nature of the drug.
So the increase in chakra from this experimental product ultimately depended on the user's "absorption." Different individuals would experience different levels of improvement.
Moreover, the growth wasn't instantaneous—it was a gradual, long-term process rather than something achieved overnight.
"So all I need to do now is go back and wait?" Shimizu asked.
"Precisely. And it won't interfere with any of your activities," Orochimaru replied.
Something this good… he wished he could take a dozen doses.
If that were possible… becoming a human tailed beast wouldn't just be a fantasy anymore.
As if reading his thoughts, Orochimaru immediately poured cold water on the idea. "However, you only get one effective dose. A second time will yield almost no results."
Drug resistance?
"You haven't tried it on yourself before?" Shimizu asked, surprised.
He had assumed Orochimaru understood it so thoroughly because he had already used himself as a test subject.
"Without fully understanding the properties of the Hero Water, why would I take such a risk?"
That made sense. At this stage, Orochimaru was still a relatively "normal" shinobi—he had no need for body-switching techniques, and with access to Hashirama's cells, there was no reason to recklessly damage his current body.
With the Hero Water now consumed, things were settled. Shimizu was ready to leave at any moment.
However, there was still about half a cup left—and Orochimaru didn't seem inclined to give it to him.
"This remaining amount isn't sufficient to significantly enhance an adult's chakra reserves…"
"I intend to give it to Erugetsu. He's always wanted to become a shinobi."
"But the child's aptitude is simply too poor. He can't even mold chakra."
"Perhaps this Hero Water might allow him to realize that dream…"
Orochimaru was playing the emotional card?
And he still claimed the boy wasn't his?
"…Fine. Do as you like," Shimizu said.
It didn't matter much to him anyway. As for giving something this overpowered to the people around him…
No—on second thought, that wasn't necessary. Kakashi, Shisui… every one of them was already exceptional, and they were all in a phase of rapid growth. They didn't need external enhancements like this.
"Uzuki-kun is as straightforward as ever."
Letting go of a small advantage like this didn't bother Shimizu. Besides, maintaining a good relationship with Orochimaru promised far greater long-term benefits.
"Do you have an estimate? How much will the chakra increase after taking it?"
"The experimental data varies widely between individuals, but most cases show an increase between fifty percent and double, with the effects developing over roughly three months."
That much?!
Shimizu's current chakra reserves were already about three times that of an average elite jōnin.
If that increased by another fifty percent—or even doubled—he would be stepping into Kage-level territory.
After all, the higher one's chakra reserves climbed, the harder it became to improve further, as it approached the natural limits of the human body.
But if he could truly cross that threshold…
Just the thought of it was enough to make him smile even in his sleep.
And it would only take three months.
"Orochimaru… you're certain there are no side effects?"
"If there were, would I have taken it myself?"
With his heart brimming with anticipation, Shimizu left the underground laboratory.
Even his steps felt lighter on the way back… as though he could already see himself three months from now, standing at the very edge of Kage-level power, his chakra reserves vastly increased.