Naruto: I Can Upgrade My Techniques Infinitely-Chapter 55: Battle! Hell Yeah!

Unfortunately, mastering those mysterious syllables wasn't going to be easy.

After all, it had taken the sacrifice of Hidan for Nara Kazuki to even hear a single sentence from that unknown entity—and that alone had nearly split his skull from the pain.

What kind of result the next sacrifice might bring? No one could say.

"Forget it for now. I'll just keep refining chakra. As an Anbu, I get plenty of mission opportunities anyway." Kazuki yawned and glanced at his chakra refinement progress. It had gone up again—a good sign.

He was getting close to the next milestone. At this rate, if he kept grinding, he'd max it out within a day.

Stretching, Kazuki created a Shadow Clone to keep up the grind while he headed home to rest and continue stacking skill proficiency.

Training was tedious. When Kazuki finished a cheap instant ramen breakfast the next morning, his chakra refining bar finally filled up.

Without hesitation, he hit [Upgrade].

And the system gave him three options:

[Stealing Heaven's Craftsmanship]: Each time you refine chakra, your body's affinity with natural energy slightly increases. The higher your affinity, the faster you can absorb natural energy and convert it into Sage Chakra.

[Plain But Practical]: Your chakra usage is now extremely efficient. All jutsu consume 60% less chakra.

[Battle! Hell Yeah!]: Every time you kill a hostile shinobi, your total chakra (physical and spiritual energy) increases by 1%.

"...You've gotta be kidding me," Kazuki muttered, stomach twisting.

All three upgrades were amazing. He wanted them all. But of course... he could only pick one.

"I'm going to end up with analysis paralysis at this rate," Kazuki grumbled.

The first one was tempting: passive natural energy affinity with every bit of chakra refining. Over time, that meant easier Sage Mode. Someday, like Hashirama, he could snap his fingers and enter Sage Mode on the spot.

Sage Mode was no joke—it was a massive power boost. The real issue with it was how long it took to activate. Naruto and Jiraiya couldn't enter it instantly. Only Hashirama could.

But with this perk, he could eventually close that gap.

The second option was brutally effective too: cutting chakra costs by 60% meant every jutsu could be spammed. In practical terms, it was like multiplying his chakra pool several times over.

Then there was the third one...

A killing machine perk. For every enemy ninja he eliminated, his total chakra pool would permanently increase by 1%, including physical and spiritual energy.

It was essentially the murder-fueled growth route.

Each option offered a massive boost, but if Kazuki was honest, option two was probably the strongest in the short term.

"...Why can't I pick more than one?" he sighed.

Dropping any of the three felt like losing a treasure. But if he had to sacrifice one, it would likely be option two. That kind of efficiency could potentially be made up through other means. The others were harder to replace.

Suddenly, a new notification popped up:

[Upon completing special achievements, you will earn a single rollback token. You may use it to claim one missed upgrade.]

Kazuki's eyes widened. That was the first time the system had ever responded to his whining.

"How do I unlock that achievement?" he asked excitedly.

Another window opened. Inside, a list of achievements—most of them greyed out with question marks. Only one was visible:

[Night of the Nine-Tails]: Successfully defeat Uchiha Obito during the Nine-Tails incident. Prevent the death of the Fourth Hokage and his wife. Protect Konohagakure to complete this achievement.

Kazuki twitched.

He'd expected a challenge, but that?

Obito, at that point in time, would already be wielding the Mangekyō Sharingan, with Kamui, not to mention the backing of Black Zetsu. Beating him wouldn't be easy—but it wasn't impossible.

Especially considering Obito was expecting a one-man job.

Kazuki reasoned that this time around, if Obito tried to breach the village, he wouldn't just be facing Minato Namikaze. Jiraiya was also in the village. If they planned things right...

If he could convince Jiraiya to guard Kushina's delivery site, then Obito would hit a brick wall of Sannin-tier defense.

Even with Kamui, it wouldn't be easy to get through.

"...Obito," Kazuki muttered, cracking his knuckles. Right now, that guy didn't look like a villain to him—he looked like a walking achievement piñata.

With that in mind, Kazuki made his decision.

He picked the third option:

[Battle! Hell Yeah!]

After all, he already had a good relationship with Jiraiya. Once he reached the right level, it wouldn't be hard to ask him for training in Sage Arts.

If he picked the natural energy perk now, he'd only be prepping for something he couldn't learn in time before the Nine-Tails attack.

But the combat route—that he could start on immediately. As long as he took more Anbu missions and stacked enemy kills, his chakra pool would grow—and fast.

By the time Obito came knocking, Kazuki might be a whole different beast.

Sure, Sage Mode could come later.

But beating Obito came first.

"Time to grind! Time to kill! Time to grow!" Kazuki declared, eyes shining like a battle junkie.

Just thinking about it made his chakra itch with anticipation.