The full name of the ANBU is the "Special Assassination and Tactical Squad." It was originally created by the Second Hokage, Senju Tobirama. You could say that the ANBU of every other village copied Konoha's homework — and then each village's Kage added their own creative twists. That's how the various ANBU units came to be in their present form.
Over the decades,
the ANBU of each village developed differently.
The ANBU of Kumogakure, Sunagakure, and Iwagakure were, to be honest, fairly unremarkable. Only Kirigakure's ANBU showed notable improvement. Of course, this could be attributed to the fact that the Kiri-nin's natural combat style aligned well with the principles the ANBU were built upon, making ANBU operations in the Kiri grow rapidly.
Oniyuzu Anjō had also served in the ANBU when he was young.
So—
when Konoha's ANBU began sweeping through the entire embassy,
Anjō couldn't help but examine the Konoha ANBU with a critical eye, silently comparing them to the ANBU of Kirigakure.
And then…
he had to admit that Konoha's ANBU really were worthy of being called the "ancestor" of all ANBU. They truly had skills.
This ANBU operative named Aburame Kenshira, along with the subordinates under his command, demonstrated impressive technique, thoroughly turning the embassy inside out in the blink of an eye.
After that—
"Hokage-sama, this subordinate is incompetent. I found no clues."
Aburame Kenshira dropped to one knee before the Third Hokage, lowering his head as though weighed down by shame.
"You found nothing at all?"
The Third frowned, his expression growing even more solemn. Ignoring the fact that the Kiri-nin were present, he asked bluntly:
"Is it possible that Mizushiro wasn't abducted — but left on his own?"
Beside him,
Anjō immediately let anger flash across his face.
But he restrained the righteous fury of someone falsely accused. He even raised a hand to stop his subordinates from reacting, simply observing quietly as the Hokage and Kenshira spoke.
"Unless that person possesses a space–time technique."
Kenshira answered, elaborating in detail:
"That Kiri-nin—Mizushiro—had his chakra trail cut off suddenly on the second floor of this corridor. There are no traces of him leaving the embassy. Whether he was taken or left on his own, as long as it happened through normal means, there would absolutely be signs."
"In other words, the only way to leave no trace… is through a space–time technique?"
The Third was also a top-tier ninja. Though not a sensory-type himself, Kenshira was an elite among the Aburame, and the most skilled tracker in the ANBU. Hiruzen had no reason to doubt his judgment.
So he began considering the space–time angle.
No one had ever heard of someone in Kirigakure who mastered any space–time ninjutsu beyond the basic Summoning Technique. In fact, the number of practical combat space–time jutsu was exceedingly small. Aside from Flying Thunder God developed by Tobirama, the only other notable one was Kumogakure's Heavenly Transfer Technique.
At present,
the only person in Konoha who could use Flying Thunder God was Minato.
And the Heavenly Transfer Technique…
made quite the scene when used — very far from subtle.
At that moment—
Kyoichi suddenly spoke:
"Is it possible the attacker possesses some extremely advanced method of masking chakra signatures?"
Kenshira glanced at Kyoichi but said nothing.
"We can't rule that out,"
the Third responded, turning his gaze to him.
"But… a technique so precise it can evade a top-tier sensor's search… such a thing is unheard of. Don't tell me Kirigakure has such a secret art?"
"Kirigakure has nothing that impressive."
Kyoichi shook his head, meeting the Third's eyes calmly.
"If we had something like that, we wouldn't have lost the previous war… My apologies, Hokage-sama. I was thinking too wildly."
As he spoke,
his mind drifted to a certain half-black, half-white pitcher plant creature.
If he remembered correctly,
that thing possessed the most advanced stealth technique in the entire shinobi world — even top sensory skills could not detect Zetsu.
Moreover,
Kyoichi had long suspected that Mizushiro had ties to Uchiha Madara. Perhaps… Mizushiro had already been replaced by a White Zetsu. He distinctly recalled that in addition to unmatched stealth, White Zetsu also had a transformation technique of extraordinary caliber.
Aside from Naruto's malice-sensing ability in the Nine-Tails Chakra Mode,
even the Byakugan could not see through White Zetsu's transformation.
Which explained perfectly why Kyoichi hadn't detected anything off about Mizushiro, even though he had subtly sensed something strange. And there was also Ringo Ameyuri… that girl's sensory ability seemed extremely sharp as well.
Still—
these were thoughts for later.
For now,
if his guess was right,
Mizushiro really was a White Zetsu impostor.
And that made him wonder what Zetsu — or Madara — intended to do.
Letting "Mizushiro" infiltrate the Seven Ninja Swordsmen, then enter Konoha as part of the delegation… and then making a move on the very first night…
What exactly were they planning?
While Kyoichi pondered,
the Third Hokage was also thinking.
One by one, he eliminated possibilities, and eventually narrowed it down to one likely conclusion—
"Reverse Summoning."
Everyone knew that the Summoning Technique was the most widespread space–time ninjutsu, allowing one to summon distant animals or tools to one's side. Reverse Summoning, on the other hand, was when the summoned creature summoned its contracted ninja back.
However—
Unlike normal summoning,
Reverse Summoning had a much higher threshold. Only highly intelligent summoning beasts with chakra-training capability could perform it, summoning the ninja when needed.
"Reverse Summoning? So that's also possible..."
Anjō finally realized.
He knew of Reverse Summoning, but he had no summoning beast capable of it — so the thought simply hadn't occurred to him.
Even Kyoichi gave a slight nod.
Aside from the possibility that Mizushiro had been White-Zetsu-in-disguise, they could not rule out Reverse Summoning. Even he had to reconsider his earlier conclusion.
He had to admit—
The title "Professor" for the Third Hokage truly seemed well-earned.
And just then—
"Hokage-sama! Something has happened to the Uchiha clan!!"
An ANBU operative darted to the Third's side, completely ignoring the Kiri-nin present, and shouted the words that shocked everyone on the scene.