Hiruko was just an ordinary Konoha Jonin, neither holding important positions nor having the kind of fame like Orochimaru and the others, so his defection didn't cause much trouble for Konoha.
During the war, Konoha was too lazy to even send a Jonin squad to pursue him, only symbolically sending someone to check it out, and left it at that when nothing was found.
In the grand scheme of Konoha, Hiruko's defection was like a towering tree losing a small branch, insignificant to the bigger picture.
However, even a small branch on a towering tree has leaves connected to it, and to Hiruko's friends, this was no trivial matter.
Orochimaru didn't have many friends, not because he couldn't make any, but because most people weren't qualified to be his friend.
Hiruko was one of Orochimaru's few friends.
They were classmates, and had been friends since their school days.
Even though later on Orochimaru and the others became the legendary Sannin while Hiruko remained an ordinary Jonin, Orochimaru and the others never minded this, and continued their relationship with Hiruko as before.
However, according to the information recovered from Hiruko's lab, while they didn't care about Hiruko's strength, Hiruko himself cared a lot about it.
"Too reckless." Orochimaru put down the information, shaking his head slightly.
He conducted human experimentation with Danzo's help covering it up; Hiruko doing it alone was bound to be exposed sooner or later.
Even though Konoha has the word "village" in its name, it is not truly a rural village; its essence is that of a military base.
Orochimaru showed a hint of regret on his face; while Hiruko seemed to have decent research capabilities, if he had joined the collaboration between him and Danzo, he wouldn't have ended up in this situation.
However, since Hiruko had already defected, Orochimaru would not indulge in meaningless reminiscing as he had many matters to attend to.
Orochimaru decided to use his former friend to test Mokgetsu's attitude towards human experimentation.
While they were inspecting the work of various units in the camp, Orochimaru suddenly said, "Mokgetsu, did you know that recently a Jonin defected from Konoha?"
"Not really, who was it?" Mokgetsu shook his head in response.
He hadn't received this information, but Mokgetsu assumed it was just an ordinary Jonin, and that what he did didn't significantly affect Konoha's interests; otherwise, news would have spread by now.
Orochimaru wasn't surprised by Mokgetsu's response, as although Hiruko wasn't an important figure, defection was never a good thing, and Konoha wouldn't publicly advertise it.
Orochimaru had received the information partly because Sarutobi Hiruzen knew about his relationship with Hiruko, and partly because Danzo thought Hiruko's research might be useful to Orochimaru, so he provided him with the whole story and Hiruko's leftover materials.
"Hiruko," Orochimaru answered.
"So it was Senior Hiruko, that's surprising," Mokgetsu put on a surprised expression.
"You know him, Mokgetsu?" Orochimaru was a bit surprised.
"Not very well, just worked together as examiners for the Chunin Examination. Senior Hiruko seemed very quiet, like someone who abides by the rules; I didn't expect him to defect," Mokgetsu explained.
At this point, Mokgetsu roughly guessed Orochimaru's purpose.
Having seen the script, he knew the reasons for Hiruko's defection were similar to Orochimaru's in the future—conducting human experimentation, though Orochimaru would be even more serious, illegally researching Hashirama Cells and such.
"Actually, he was my friend. We were in the same ninja class. I also didn't expect him to secretly capture innocent people from nearby villages for human experimentation," Orochimaru sighed slightly, as though feeling melancholy over losing a friend, while observing Mokgetsu's facial expression from the corner of his eye.
He wanted to know Mokgetsu's true attitude towards human experimentation, as it was meaningful to Orochimaru.
If Mokgetsu was very interested in human experimentation, Orochimaru could completely bring him onto his side and bind him tightly, forming a mutually beneficial relationship between him and Danzo.
If Mokgetsu wasn't interested but didn't oppose it, Orochimaru could still safely reveal some secrets to him and make him a confidant.
If Mokgetsu was strongly opposed, Orochimaru would have to be careful while using him, ensuring Mokgetsu wouldn't learn of his secret research on Hashirama Cells.
"That's very excessive and extreme, to actually capture innocent people for human experimentation," Mokgetsu stated bluntly.
Mokgetsu didn't dislike all human experimentation, acknowledging that some research indeed required it, but when it involved innocent people, Mokgetsu would only say it served Hiruko right.
Orochimaru carefully considered Mokgetsu's words before speaking, "Hiruko was indeed somewhat extreme. For some ninjutsu, human experimentation is a necessary process. The village has organized human experiments before, but the subjects were usually death row inmates and volunteers. Capturing innocent villagers is truly inappropriate."
Mokgetsu nodded in agreement.
Seeing this, Orochimaru roughly understood Mokgetsu's stance on human experimentation—not completely opposed but with a condition to not harm the innocent.
"Mokgetsu has still experienced too little. I hope the upcoming war will let him realize the fragility of life," Orochimaru believed Mokgetsu still had room for growth.
After all, people always change; even Orochimaru now is very different from the Orochimaru of ten years ago.