The Mayfly Technique was a signature jutsu of Zetsu. It was difficult to classify which nature this technique belonged to.
Once activated, it allowed free movement through networks of earth, plants, and even underground rivers—effectively involving Earth, Wood, and Water elements. Essentially, it was an exceptionally advanced infiltration technique.
Moreover, when White Zetsu used it, there was no sound or trace. They didn't need hand seals like ordinary shinobi. It was almost an instinct—or perhaps a Bloodline Limit.
Thus, countering this technique through elemental properties was virtually impossible. The only approach was through unpredictability.
Yet achieving unpredictability was no simple matter either.It's important to note that while most White Zetsu aren't particularly strong in combat, their sheer numbers make up for it. Among the hundred thousand White Zetsu, there are bound to be quite a few with considerable strength.
Moreover, those monitoring Konoha couldn't possibly be ordinary. Aoba considered that they must at least have Jonin-level abilities.
Additionally, White Zetsu possess another formidable trait—their vitality is incredibly robust. Conventional methods can hardly kill them.
These creatures are no longer human. Their essence is closer to that of plants, and plants can't be killed by a single sword thrust.
Therefore, to ambush and subdue them instantly, Aoba had to return to his current studies—sealing techniques.
Aoba needed to develop a convenient sealing technique that could instantly block all of a White Zetsu's Chakra and mobility.
This problem was, in a way, both difficult and not. After researching for several days, he had basically no leads.
It wasn't that there were no similar sealing techniques, but rather that these techniques were generally not quick enough—slower than ordinary ninjutsu.
Such techniques were typically used after subduing an enemy, ensuring they couldn't recover Chakra to escape or counterattack. In short, the Shinobi World currently lacked the kind of sealing technique Aoba envisioned—one that could instantly block all of an enemy's Chakra.
If such a sealing technique truly existed, it would surpass ninety-nine percent of ninjutsu in effectiveness.
However, one day while having a meal with Kakashi, he casually mentioned this idea. To his surprise, Kakashi gave him an unexpected response.
"You mean the shackles used by the Interrogation Team?"
Aoba realized he had made an empiricist error.
Previously, when researching techniques to seal vitality, he had developed them from scratch. When it came to sealing Chakra, he instinctively wanted to do the same.
But he forgot that this was a world of Chakra. There were countless sealing techniques targeting Chakra. While directly using these techniques wasn't practical enough, they could be employed with tools.
The Interrogation Team had more than one set of such special devices. Once a prisoner was shackled, even the strongest enemy couldn't use a single bit of Chakra. They could even render the shackled person completely limp—a tool specifically designed for shinobi.
In actual combat, these devices were generally ineffective because they were used against people. The time it took to shackle someone was enough to stab them three times. Moreover, the design wasn't suited for combat.
But Aoba was dealing with White Zetsu—creatures extremely difficult to kill. They were the type that wouldn't die even after being stabbed three times, requiring restraining methods to control them.
"Kakashi, are you familiar with Ibiki?"
"Somewhat. We interacted often back in the Anbu."
"Then I have a favor to ask. Could you help me borrow a set of shackles from the Interrogation Team for research?"
The specialized tools used by the Interrogation Team employed sealing techniques that were among the few not covered in Orochimaru's data. Probably, the Snake Sage hadn't anticipated Aoba having such an unusual need.
In truth, Orochimaru's data should have been sufficient to derive similar techniques. But with ready-made tools available, Aoba decided to use them directly. There was too much to research, and time was limited.
"What do you need those for?""I've been researching a special kind of kunai recently. The kind that can restrict an enemy's chakra upon hitting them."
"Restricting chakra is clearly an inefficient approach. If you want to increase a kunai's lethality, you could simply coat it with poison. The Aburame clan sells similar toxins, or you could extract some snake venom from the forest yourself."
"..." Discussing such matters with professionals was always troublesome like this. There was no way to gloss over the details.
Aoba let out a somewhat helpless sigh.
"Alright, the truth is it's related to a special research project of mine. A very special one."
Kakashi immediately understood—it was the kind of thing that couldn't be discussed openly. But he didn't press further. Mainly because the interrogation squad's shackles were, in their own way, quite complicated.
These shackles were forged from a special chakra-conductive metal. They were expensive to produce and limited in quantity.
Yet, in another sense, they weren't complicated at all. Even members of the interrogation squad rarely paid attention to their inventory.
Only high-value prisoners with formidable strength would warrant their use. Under normal circumstances, the interrogation squad could completely break a ninja using just conventional methods. There was hardly ever a need for such costly tools.
After some thought, Kakashi spoke.
"Aoba, I can help you with this. And I won't ask for the reason. But I need you to promise me that your research won't harm Konoha."
Aoba didn't answer directly. Instead, he countered with a question.
"Kakashi, why would you think I'd harm Konoha? I've never done anything to betray the village."
"But you've thought about it, Aoba. I can tell—you resent Konoha for marginalizing you back then. No, it's more than resentment. You hate them."
For the first time, Aoba realized that just as he understood Kakashi, Kakashi understood him just as well. He had thought his facade was flawless, yet Kakashi—one of his few friends in Konoha—had seen through some of what he'd hidden.
Though not entirely accurate. Aoba didn't hate Konoha's leadership—he disliked them. His marginalization had, in part, been his own doing. But his distaste for the village's higher-ups was genuine.
And this concealed emotion had been interpreted by Kakashi as hatred for Konoha itself.
"I have to say, Kakashi. Your cold exterior always makes people overlook how perceptive you are. But before I answer your question, I need to ask you one in return. If you can answer me, then I'll answer you."
"...Fine. Go ahead."
"Good, Kakashi. Tell me—what exactly is Konoha?"
Without waiting for Kakashi's response, Aoba stood up, paid the bill, and left.
"Think carefully before you answer."