Shigure's calculation speed was terrifyingly fast.
He hadn't even noticed how quickly it finished.
On the other hand, Naruto hadn't even popped a single balloon yet, still struggling with his training.
Then came the notification in his mind:
[Congratulations to the host for acquiring a new skill: Boiling Release — Heat Breath Blade]
[Boiling Release: Heat Breath Blade — By precisely manipulating chakra, this technique modifies the properties of Boiling Release through the layering of two distinct chakra densities.]
[The first layer, a high-density chakra coating, radiates extremely high temperatures, enhancing the destructive power of the weapon through sheer heat.]
[The second layer of standard-density chakra emits a corrosive vapor. It doesn't affect the user, but anything it touches will begin to corrode.]
[Upon contact with the enemy, the blade injects the corrosive steam into their body, burning their flesh from the inside and causing intense internal damage. The lethality is considerable.]
Reading through the details, Shigure smiled.
This wasn't just some flashy gimmick.
It had real power.
The ability to inject Heat Breath into the target on contact… that was deadly.
Of course, the amount of damage depended on the duration of contact, but even a momentary strike would be enough to numb the affected area.
And once the corrosive vapor slipped inside…
"It'll rip them apart from the inside out."
"This technique is seriously good."
Without hesitation, Shigure drew Zangetsu, the dark-bladed ninjatō glowing faintly blue along its edge.
Forming a one-handed seal, he called out:
"Boiling Release — Heat Breath Blade."
Hissss—!
Naruto, startled by the strange noise, glanced over—and froze.
His eyes slowly widened in shock.
Shigure stood holding Zangetsu, steam rising from the glowing blade like a kettle about to boil over.
A constant hissing sound escaped the blade as steam curled into the air.
Shigure could feel his chakra draining.
"As expected of Boiling Release… the chakra consumption is no joke."
But this variant was different from the Boiling Release he'd used before.
The earlier version flooded his entire body with volatile chakra—boosting his power massively but locking him out of other ninjutsu. It was too risky in extended fights.
This, however…
Even while maintaining Heat Breath Blade, he could still use other ninjutsu.
That meant more flexibility, more strategies, and far fewer moments of helplessness in a real battle.
He wouldn't be caught flat-footed again.
Sure, he couldn't combine it with his Breathing Techniques…
But basic swordplay? That still worked just fine.
And Shigure's swordsmanship?
Even without enhancements, it was enough to overwhelm seasoned jonin.
Add Heat Breath Blade to that?
Deadly.
Hissss—!
Steam continued to rise. Shigure raised his sword and swung it in a wide arc.
A faint burst of heated wind followed the slash.
As mentioned in the description, the skill could inject Heat Breath on contact…
But it could also burn chakra to project an external burst—even without a direct hit.
Though the range of that kind of attack was limited, it was still an option.
And options in battle?
Could mean the difference between life and death.
The heat blast only traveled about a meter before dissipating.
Shigure raised his hand, aimed Zangetsu forward, and released his Heat Breath at full power.
With chakra surging through the blade, the steaming torrent blasted ahead. Although the speed was still relatively slow, it was essentially a fog technique in a different form.
The heat swept forward, covering five or six meters before slamming into a tree trunk. Instantly, the middle of the trunk began to melt—clearly visible corrosion eating through the bark and wood. It wasn't just heat—it was the devastating effect of Boiling Release.
Crack!
With a loud snap, the tree collapsed.
Naruto stood there, stunned.
"W-What kind of technique is that?!"
Shigure calmly dismissed the Heat Breath Blade and glanced at Naruto.
"Nothing much. Keep training. I'm heading to a more open area to test this new technique I've developed."
New technique?!
Naruto blinked in confusion. When did this guy develop a new jutsu?
Was it while I was gone?
And who just casually invents new ninjutsu like that?
Did he develop all his techniques on his own...?
Naruto's mind buzzed with questions.
But before he could ask, Shigure vanished in a blur—Body Flicker Technique.
He reappeared by a wide riverbank.
Without hesitation, he leapt into the water and drew Zangetsu once more.
This should be a perfect training spot.
Cutting through trees or stone with Heat Breath caused too much environmental damage. But in water, the damage from heat and corrosion would be more contained—less to worry about.
Since perfecting the jutsu, Shigure had replaced his passive skill 4–5 with Boiling Release: Blade of Heat.
Not only did this amplify his training effect tenfold, but it also had virtually no chakra cost due to passive enhancement.
It was the ideal setup for a full-on grind session.
He activated Accelerated Thinking.
"Let's use the rest of the afternoon to push Boiling Release toward compound fusion."
"Ice Release has already been passively cultivated for some time. It'll be ready to fuse by tonight at the latest."
Once that's done, chakra control and elemental strength will both meet the requirements.
The only remaining hurdle would be physical conditioning. But with a mission underway, Shigure could use every bit of travel—walking, running, carrying gear—as training.
By the time he returned to Konoha, his body should be in top shape.
Perfect. Not a second wasted.
"Start."
As he began swinging Zangetsu in rapid arcs through the air, waves of heat erupted around him.
The fast-flowing river around him started steaming, bubbling violently—like a natural hot spring cranked to its highest setting.
The heat kept rising.
The power of Boiling Release surged dramatically. Even the river's constant movement couldn't prevent the corrosion; anything in contact with the boiling stream began to wear away.
But this intense chakra usage was exactly what Shigure needed. The faster his chakra was consumed, the more property transformations would be triggered.
He could feel the blade growing hotter, more dangerous, with every swing.
The corrosive power of Boiling Release was rising fast—sharper, deadlier, and more precise with each passing second.
I only came here to avoid damaging the village environment...
But it looks like I've stumbled onto the fastest way to evolve this technique.
If this pace kept up, he'd definitely reach the Great Sage's required level of nature transformation for Boiling Release before the sun even set.
...
TN:
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