Time flew by, and it was already late afternoon.
Inside the room, Uchiha Haruki slowly opened his eyes and looked at his empty palm. Then he picked up the book beside him again and resumed reading with focused attention.
After a while, he sighed and muttered,
"Sigh… As expected, developing a fourth chakra nature isn't easy."
In the ninja world, excluding those with Kekkei Genkai or special bloodline limits, the vast majority of shinobi are born with only one chakra nature.
In fact, most retain only that one nature until they reach jōnin level.
It's only after becoming a jōnin that they typically begin developing a second chakra attribute to cover their weaknesses.
Some geniuses might start earlier—perhaps during the chūnin stage—but even then, over 90% of them only manage to master two chakra natures in the end.
This isn't because they don't want to progress further—mastering multiple chakra attributes obviously enhances combat power. No one would give up on that if they had the chance.
The truth is, most simply can't do it.
If developing one's innate chakra nature has a difficulty of 1, then the difficulty of acquiring a second is around 5.
That level is still within reach for moderately talented shinobi.
But when it comes to mastering a third chakra nature, the difficulty jumps to 10.
Don't be fooled by the number only doubling from the previous level—it's actually ten times harder than developing your first attribute.
At this stage, unless a shinobi is truly exceptional, they're effectively blocked from progressing further.
Currently, more than half of the jōnin in the entire ninja world are stuck at this point.
As for a fourth chakra nature—based on Haruki's own experience so far—the difficulty is at least 20.
Under those circumstances, if you're not a prodigy, there's really no point wasting your time.
Even if someone does manage to force their way through and unlock it, it might not even be very useful in practice.
They'd be better off sharpening the skills they already have—that would likely bring more noticeable improvements.
That said, Uchiha Haruki wasn't planning to give up.
For one, he had the proficiency panel, meaning that once he unlocked the earth chakra nature, he wouldn't need to worry about the long process of mastering it.
And more importantly—its elemental advantage over water chakra made it worth the effort.
It wasn't that he was planning to specifically fight a water-style shinobi.
Rather, the five chakra natures—fire, wind, lightning, earth, and water—form a cyclical advantage-disadvantage system. Together, they create a complete elemental loop. If he was missing one, that loop would be broken.
Sure, in battle, he could often rely on his overwhelming chakra reserves to overpower his enemies.
But what if he faced an opponent with equally vast chakra—someone who also happened to wield a nature that countered his?
That flaw would become glaringly obvious.
The classic "wooden bucket theory" from his past life summed it up well:
The amount of water a bucket can hold doesn't depend on its longest plank, but on its shortest.
Haruki's determination to develop new chakra natures was his way of extending that "shortest plank."
That way, he could avoid exposing any major weaknesses.
So no matter how difficult this process might be—he wouldn't quit.
With that thought, he cleared his mind and once again began following the book's instructions to develop his earth nature chakra.
Nightfall.
Time passed in a flash. The sun set, and the moon rose.
Throughout the entire day, both the Hidden Mist and Hidden Leaf remained eerily still.
No major battles broke out—not even small skirmishes. It was as if both sides had suddenly gone blind, acting like the other didn't exist.
But Haruki knew this was simply the calm before the storm.
Just like on the Leaf's side, where for the entire day, the army had been actively repositioning troops.
Sure, ninja could move faster than ordinary soldiers, but a massive troop redeployment still took time.
That's why there hadn't been any immediate actions.
Similarly, the Mist Village was also deep in preparations.
Thanks to that, Haruki had been lucky enough to get a full day of training.
But that break was now over.
Not long ago, his official mission had arrived.
Uchiha Yatsushiro really had secured him a great assignment.
With that in mind, Haruki packed up his gear, double-checked that he had everything he needed, and stepped out of his room.
Without any delay, he quickly formed a string of hand seals and activated a jutsu:
Wind Release: Wings of Wind!
Whoosh!
A pair of pale-aqua chakra wings unfurled from his back.
With a thought, Haruki controlled the wings and gave them a gentle flap.
The next second, he was airborne.
After circling the area once, he flew straight toward Flying Fish Town.
Flying Fish Town—a coastal settlement on the eastern border of the Land of Fire.
Due to its unique geography, it was frequently hit by storms. But once the storms passed, they often brought in huge hauls of fish.
Hence the name.
The town had previously served as one of Konoha's key central defense outposts.
But now? It had become one of the four outposts overtaken by the Mist Village.
This time, their mission from Blackstone Outpost was simple:
Retake it.
And Haruki's personal mission?
Use his flying ability to gather intel on enemy movements—intel that the command unit would then use to strategize the upcoming operation.
This truly was a perfect assignment.
Given his current strength, operating under the cover of night made it nearly impossible for Mist shinobi to stop him.
It was a high-safety, high-reward job.
Most importantly—it also allowed him to rack up considerable merit.
And the village was perfectly fine with that.
After all, intelligence gathering could sometimes be more valuable than the combat power of a single jōnin.
Even if his personal power exceeded the jōnin norm, once he was dropped into a battlefield of hundreds or thousands, he'd be just one cog in the machine.
Especially now that the Mist had prepared specifically to counter airborne targets.
It was no longer realistic for him to fly around putting out fires across the battlefield like he had that night.
That's also why the village approved Yatsushiro's suggestion.
Otherwise, they'd never let someone as powerful as Haruki just "tag along" like a non-combatant.
Fifteen minutes later.
Haruki arrived above Flying Fish Town.
From the air, the entire outpost below was glowing with lights, and shadowy figures moved through it in constant motion.
Activating his Sharingan, Haruki took a closer look and saw that the figures belonged to Mist Village patrol squads.
Right now, the entire outpost was like a giant machine, with every shinobi inside acting as a gear—together powering the terrifying engine of war.
"This… isn't going to be easy."
After watching silently for a long while, Haruki couldn't help but sigh.
The Mist hadn't rushed their occupation. Instead, they had clearly fortified this location as a strategic point—using it as a base to slowly expand their territory.
If Konoha tried to take it back using only the troops at Blackstone Outpost, they'd probably fall short.
But deploying more forces wasn't realistic either.
The decisive battle with the Sand Village was already reaching a critical moment, and the Hidden Stone's distractions elsewhere had already stretched Konoha thin.
"Yeah… this is gonna be tough."
Haruki shook his head with a sigh and stopped overthinking it.
These were matters for the village leadership to worry about—not him.
All he needed to do was carry out his own role properly.
One way or another, the Leaf would eventually push the Mist back.
With that in mind, Haruki turned his focus back to the outpost below, carefully observing the internal and external layouts—and recording every detail.
This intel would need to be submitted.
Even if he planned to stay out of the main fight, he still needed to maintain a serious attitude.