Naruto: My Progress in Konoha.

The next day.

Nightfall.

Deep within the underground cavern.

Uchiha Haruki walked in, expressionless, his entire body radiating exhaustion from the inside out.

Seeing this, the captured Sunagakure shinobi appeared even more confident. Not only were they completely unafraid, but some even started to size Haruki up with mocking eyes.

Their derision was completely undisguised.

It was as if they were trying to declare victory through their expressions.

But they would never understand one truth—fish on the chopping block can thrash as much as they like, but in the end, they're still destined for the knife.

Or perhaps, deep down, they did understand. They just didn't want to face it and could only numb themselves with this illusion of superiority.

Seeing their smug behavior, Haruki forced himself to stay focused and let out a cold sneer.

"You all seem quite pleased with yourselves. Do you really think I can't do anything to you?"

As soon as he said that, for some reason, all the Sunagakure shinobi involuntarily shivered. The fear they had developed from Haruki's "torments" over the past month surfaced once more in their hearts.

"Heh…"

Watching their expressions, Haruki sneered again.

Then, with a flicker, he appeared directly in front of Shafu, the Jonin.

This time, Shafu didn't flinch at Haruki's approach—his face remained calm and unbothered.

However, that was just a facade.

Haruki could clearly sense that the closer he got, the faster Shafu's heartbeat became.

"Heh, try to bear with it... it's my first time, after all."

He said darkly with a twisted sense of humor, and then began forming hand seals.

Shafu's heart skipped a beat at that ominous comment, but when he saw the seals Haruki was making, he breathed a small sigh of relief.

He knew that technique well—it was the same jutsu Haruki had been using to drain their chakra for the past month. Nothing new.

But he celebrated too early.

When Haruki placed his hand on Shafu's head and began draining his chakra, Shafu remained calm.

However, once his chakra was completely emptied—and Haruki began forcibly extracting his spiritual and physical energy—his expression instantly changed. His eyes widened, and he began struggling.

Unfortunately, his resistance was weak and useless.

Haruki didn't even pay attention to him.

He was immersed in the strange sensation of absorbing another's life force—spiritual and physical. The feeling was... indescribable. Almost euphoric.

After a short while, Haruki came back to his senses and immediately stopped the Chakra Absorption Technique.

Looking at Shafu again—his skin was pale, cheeks sunken, breath shallow—he was in the unmistakable state of someone freshly recovering from a major illness.

Clearly, forcibly absorbing someone's spiritual and physical energy dealt serious damage to their core.

Even if Shafu recovered, it was unlikely he would ever return to his original strength. His power had probably dropped a full tier.

But what did that matter to Haruki?

To him, they were just tools for chakra supply. If they cooperated, fine. If they didn't—then they couldn't complain when he used force.

With those thoughts, Haruki stuffed a few soldier pills into Shafu's mouth and returned to his quarters to reflect on the test.

First, now that the Chakra Absorption Technique had reached Lv5, both the absorption speed and conversion rate had improved significantly.

Especially the former.

His absorption rate had doubled, increasing from 500 points per second to 1,000 points per second.

While that still wasn't as fast as the Samehada blade that could drain a Jinchūriki dry in seconds, it was definitely faster than most chakra-absorbing jutsu in the shinobi world.

As for the conversion rate…

Just as expected, it had increased by another 10%, reaching 90% efficiency.

That meant he now gained more chakra per extraction.

To put it in perspective: previously, when extracting 40,000 chakra points from the nine Sunagakure prisoners, he would convert 80%—32,000 points. Now at 90%, he'd get 36,000 points.

In other words, he had an extra 4,000 chakra points to use every day.

He already had a plan for how to use that chakra—he would invest it in training his "Mind Mirror Technique".

With that, the daily proficiency he gained from training that genjutsu would increase from 150 to 175 points.

His Sharingan's evolution into the three-tomoe stage would be accelerated, reducing the projected timeline from 21 days to just 18.

And what if the prisoners refused to cooperate or stopped refining chakra?

Too bad. That option no longer existed.

Just as he'd predicted—at Lv5, the Chakra Absorption Technique granted him the ability to directly draw out spiritual and physical energy, bypassing chakra entirely.

Granted, this lowered the conversion rate slightly—down to around 75%.

But Haruki didn't care.

He had set his quota: 36,000 chakra points a day.

If he didn't get that much, he'd make up the difference by absorbing their life force.

No mercy.

This process was undeniably painful.

And if they wanted to avoid suffering, they had only one choice: refine more chakra.

Haruki was confident they would make the right decision.

And sure enough, within just three days, the nine prisoners all gave in and began refining chakra on their own, fully cooperating with Haruki's extractions.

However, because they had resisted earlier, their cores had been damaged to varying degrees, making it impossible for them to produce enough chakra.

Haruki didn't bother arguing.

He simply continued to draw their spiritual and physical energy to make up for the shortfall.

As a result, their bodies grew weaker and weaker.

And the weaker they became, the less chakra they could provide, which meant Haruki absorbed even more of their life force.

It was a vicious cycle—one with no way out.

Their condition would only keep deteriorating.

Haruki was perfectly fine with that.

Only in this state would they stop trying to pull any tricks.

Eventually, Haruki's "vacation" ended, and he returned once more to Sector E11.

Near the base.

Inside a training ground.

Haruki scanned the area. After confirming there was no one around, he suddenly lifted his left hand.

As if collaborating with an invisible partner, he quickly formed the six hand seals:

Rat–Tiger–Dog–Ox–Rabbit–Tiger.

Then, opening his mouth, he released dozens—no, over a hundred—fireballs, successfully casting the Fire Style: Phoenix Fire Jutsu.

That's right.

Haruki had successfully cast a jutsu using only one hand.

Just as he had expected—once he trained Phoenix Fire Jutsu to Lv5 (0/0), achieving mastery, he was just a step away from one-handed casting.

Now, that final step—chakra control—had been resolved.

How?

Haruki opened his system panel and glanced at the stats.

His Chakra Control had risen from Lv3 (915/1000) to Lv4 (26/2000).

That single level-up had completely resolved the last bit of insufficient control.

From now on, not just Phoenix Fire—any jutsu of the same level, once mastered, could likely be cast with one hand.

Undoubtedly, this would become his new trump card.