"This is… Senju Tobirama's technique?"
Kakuzu had lived a very long time. Long enough that he was familiar with many figures and events in the shinobi world.
Back then, he had attempted to assassinate the First Hokage—and naturally, that meant he'd crossed paths with the Second Hokage, Senju Tobirama, as well.
Tobirama was known as the fastest shinobi of his era, a title that was only now beginning to be challenged by some upstart from the new generation. Even so, Kakuzu could never forget that man.
And aside from the mysterious Flying Thunder God Technique, Tobirama's greatest specialty had been Water Release and various forbidden and secret techniques.
His Water Release, in particular, had left an indelible mark on the shinobi world.
Ordinary water techniques were nothing special—but the techniques Tobirama developed himself were absurdly powerful.
They emphasized one defining trait: extreme compression, turning water into something with terrifying piercing and cutting power.
After Tobirama's death, water techniques like that had become exceedingly rare. They were simply too distinctive.
Which was why, the moment this white-haired brat made his move, Kakuzu recognized it.
Since it was a Second Hokage technique, Kakuzu didn't dare take it lightly.
He immediately surged chakra through his body, and his skin tone deepened as dense Earth Release chakra gathered across him.
Just as he completed the technique, Hikaru's Water Blade Slash came down.
Clang!
The sound of metal crashing against metal echoed through the forest.
Kakuzu merely raised his right arm—and blocked the attack completely.
Hikaru's blade couldn't press down another inch.
Compressed water chakra spun wildly along the sword's edge, sparks flying where steel met hardened flesh.
"This guy's Earth Release control is ridiculous…"
Hikaru felt a numbing shock run up his arm, his brow twitching.
Over thirteen years in this world, he'd spent at least half of them "planting" basic attribute fruits. The process had been painful and inefficient—but the results were undeniable.
He'd invested most heavily in coordination, speed, and reaction time. Strength had been slightly lower priority, but he hadn't neglected it either.
Speed, reflexes, coordination—those were the core markers of high-level taijutsu potential.
And as a kid, Hikaru had once fantasized about mastering Flying Thunder God, so of course he'd trained his body accordingly.
Even though the Senju clan had declined, it had left behind plenty of valuable material. Some was handed over to Konoha—but Hikaru had his own copies.
His raw strength might not have been extraordinary, but it was on par with grown adults. Otherwise, there was no way a thirteen-year-old with mediocre bloodline development and subpar chakra reserves could possess jōnin-level combat ability.
And yet—
Even with ninjutsu enhancement, even going all out, he couldn't cut through Kakuzu's defense.
That was absurd.
Before Hikaru could dwell on it, movement in his peripheral vision snapped his attention back.
The fist whose threads he'd severed twitched slightly.
Without hesitation, Hikaru activated Body Flicker.
The instant he vanished, that detached fist erupted from the ground and smashed into the spot where he'd just been standing.
"So it really is Earth Grudge Fear. I already sensed chakra underground—this bastard really is vicious."
Hikaru cursed inwardly.
By the time he landed, his hands were already flashing through seals.
"Water Release: Water Severing Wave!"
A razor-straight jet of ultra-high-pressure water blasted from his mouth, compressed to the extreme and sharpened into a lethal water blade.
At this point, Kakuzu was certain.
This white-haired brat was absolutely connected to Senju Tobirama.
These techniques were exactly the Second Hokage's signature moves.
"A descendant? Or a prodigy Konoha deliberately raised?"
Kakuzu considered it briefly—but didn't dwell on it.
The technique was troublesome, yes, but still not enough to shatter his defense.
Not the white-haired brat's Water Release…
And not the other kid—Kakashi—either.
"Since this is getting interesting, I'll play around a bit more. Then I'll deal with Kakashi and collect another hefty bounty."
Kakuzu didn't move.
And as expected, events unfolded just as he predicted.
Hikaru's Water Severing Wave was powerful, but he wasn't using Sage Mode, and his overall strength was still only jōnin-level. Breaking Kakuzu's defense was unrealistic.
The jet sliced apart the black threads again before slamming squarely into Kakuzu's body.
This time, Kakuzu was pushed back a step.
Cracks spread across his chest.
But that was all.
Shinobi defenses were generally weak—but Earth Release specialists always developed body-enhancing defensive techniques, especially ones applied directly to themselves.
And someone who had lived as long as Kakuzu had perfected self-protection to an extreme degree.
In the original timeline, once Kakuzu lost his Earth-nature heart, he had very little resistance left. After that, even ordinary attacks could kill him.
"And in canon, it was Kakashi's Lightning Release that destroyed your strongest defensive heart."
Watching Kakuzu fight with a casual, almost playful attitude, Hikaru smiled slightly.
Because Kakashi was in position.
Kakuzu suddenly frowned, sensing something off.
But Hikaru abruptly cut off his technique and used Body Flicker again, closing in and forcing Kakuzu to focus on him instead of searching for Kakashi.
"—!"
Kakuzu's eyes widened.
The piercing screech of Chidori, the violent pain in his chest, and the numbing paralysis that followed—
He looked down in disbelief at the hand that had pierced straight through his torso.
"You…"
He'd underestimated them.
These two brats actually knew how to work together.
Kakuzu wouldn't truly be harmed—but losing his Earth Release heart still filled him with rage.
Unfortunately, full-body paralysis meant he couldn't act immediately.
Hikaru, who had originally been charging toward Kakuzu, instantly changed direction.
In one smooth motion, he rushed to the corpse, swung his blade, and cleanly severed the head.
The movement was fluid, practiced—clearly not his first time dealing with this kind of situation.
No hesitation. No wasted motion.
He flashed Kakashi a tactical hand sign, grabbed the head, and turned to flee—leaving behind only a black blur vanishing into the forest.
Both Kakashi and Kakuzu froze for a split second.
Kakashi recovered first, yanking his hand free from Kakuzu's chest and immediately chasing after Hikaru.
Kakuzu, on the other hand, was completely dumbfounded.
Even after switching hearts, the lingering paralysis prevented him from giving chase right away.
By the time he recovered, the two ANBU were long gone.
Staring at the empty forest, Kakuzu's face twisted.
"…Just what kind of bastard did those brats crawl out from?"