Shinobi combat is a battle of information.
While Ren Uchiha used taijutsu to attack and Kakuzu retaliated in kind, the elder wasn't just venting his rage; he was testing the waters. After all, this brat had brazenly activated a barrier, charged in alone, and confidently claimed he could cover his teammates' escape. Kakuzu didn't believe for a second that the boy didn't have an ace up his sleeve.
Caution was the greatest reason Kakuzu had survived from the Warring States period to the present day. Ever since he had been slapped by that man's wooden clone, Kakuzu's perspective had become remarkably clear. He had carved the word "caution" into his very marrow.
Now, as he watched Ren Uchiha stand firm once more after weathering a storm of taijutsu, looking like an undying monster with his wounds fully healed, Kakuzu narrowed his eyes. Aside from appearing a bit winded, the boy's condition was far too good.
"Medical Ninjutsu? No, that healing effect is too potent; something is wrong." Even if someone used Mystical Palm Technique while fighting, it wouldn't be this exaggerated.
Thinking of this, Kakuzu slightly tilted his head toward the top of the cliff. He remembered there was a tall, middle-aged man in a yellow coat standing there—Shinno. The feeling that man gave off was subtle, but it gave Kakuzu the impression that he would be very hard to kill.
Suddenly, Kakuzu froze, glancing outside the barrier. Without him noticing, that middle-aged shinobi in the yellow coat was now standing on the cliff wall outside the barrier, his expression filled with an inexplicable shock as he stared at the "broke brat."
In that instant, Kakuzu felt he understood everything. That terrifying forbidden jutsu... that guy taught it to this kid! Are they master and disciple? Is he surprised by how much his student has progressed? Or is he using me to forge his disciple?
Kakuzu's brow furrowed. The situation was getting complicated. This kid was setting up barriers for 1v1 duels, using troublesome forbidden techniques, and isolating himself from his team—it was as if he was daring Kakuzu to kill him.
"Who is scamming who here?" Kakuzu muttered. It was clear now: this boy had a powerful backer! With that realization, Kakuzu's mindset began to undergo a subtle shift.
On the battlefield, Ren Uchiha stared at Kakuzu, his gaze focused. He mentally checked his internal state. After using Forbidden Jutsu: Physical Rebirth, his body felt like a rusted machine—stiff and uncooperative.
As powerful as the technique was, its side effects were staggering. Shinno could use it without consequence because he was plugged into the Zero-Tails' chakra. Orochimaru could use it because he simply swapped bodies when one wore out. But Ren was burning his own literal life force.
He estimated that in his current state, he could use the technique at most two more times before he would need immediate medical attention. Otherwise, he would simply drop dead from exhaustion. He only had two chances left.
Ren took a deep breath, his Sharingan leaving a streak of light in the air. He lunged forward again in the same sprinting posture as before, but with one major difference: this time, he held a whirling blade of water entrusted to him by Mei.
Water Style: Water Fang Blade!
Shoo! Shoo! Shoo! Three shuriken tore through the air.
"The same trick again?" Kakuzu narrowed his eyes. He shifted his stance and whipped out three clusters of Earth Grudge Fear tentacles. He knocked the shuriken aside and surged toward Ren with overwhelming force.
After the previous exchange, Kakuzu had a rough estimate of the boy's reaction speed. It was... a bit freakish. If it weren't for his unique body structure—using threads to catch the kunai—the boy's "ankle-cutting" combo might have actually succeeded earlier.
Now that the brat had drawn a water blade capable of severing his threads, Kakuzu wasn't about to stand still and let Ren "give him a pedicure" again. The scale of the battle began to escalate.
Seeing Kakuzu change his move and fire off a cluster of threads, Ren felt a surge of joy. This water blade is a much better 'scamming' tool than a kunai! Before he even reached the elder, Kakuzu had "donated" a pile of high-quality ninja tools! Ren slammed his heels into the cliff face, braking hard. He flourished his sword in a beautiful arc, his Sharingan locked onto the incoming tentacles.
He braced the blade against his arm, lunged, and swung!
First came Cloud Style: Deceptive Slash, tricking the tentacles into grazing his right shoulder, followed immediately by Cloud Style: Crescent Moon Slash!
It was a perfect replication of the Cloud Style swordsmanship he had seen only once in the volcanic sea of boiling water. The whirling Water Fang Blade lit up the night with three moon-like arcs.
Cing! Cing! Cing!
The three tentacles Kakuzu had fired were severed instantly. Ren dropped to a crouch, scooping up the mass of severed threads from the cliff face like a gambler raking in his winnings. He stuffed the whole handful into his tool pouch.
He then spun around and bolted like the wind, rolling and diving to dodge several retaliatory tentacle strikes. Amidst his maneuvers, he pulled out an empty wire spool and frantically began winding the tangled Earth Grudge Fear threads onto it.
Only when the spool was full did Ren flash a triumphant, "white-proffit" grin.
Though Ren seemed to have a long list of ninjutsu and forbidden techniques, if one ignored the flashy but harmless fireballs, the only things that could truly threaten Kakuzu were the two techniques he had "borrowed" from Elder Uchiha Setsuna:
Uchiha Style: Manipulated Shurikenjutsu!
This was the core of Ren's entire tactical array. It boiled down to one word: Speed. Fast enough that the opponent couldn't form seals, couldn't release ninjutsu, and couldn't defend! In a state where the enemy could only struggle to dodge, they would inevitably leave a fatal opening for Ren to seize.
A third-rate Uchiha uses shuriken for feints. A second-rate Uchiha uses them for sneak attacks. A first-rate Uchiha uses them to seize opportunities.
But at the "Master" level, Uchiha Style: Manipulated Shurikenjutsu was an S-Rank technique... because the technique itself was the killing blow!