"Have I... truly comprehended it?"
Umino Yoru sheathed his sword, feeling a faint warmth pulsing through his bones and chakra pathways.
According to Maruboshi Kosuke's teachings, the essence of Iaido (Draw-Cut) lay in **"sincerity begets enlightenment"**—a philosophy of honing one's spirit to achieve breakthroughs.
Yet here he was, having achieved his breakthrough through classical physics and mechanics instead.
Maruboshi's training was steeped in abstract, almost mystical idealism—while his own approach was rooted in cold, hard realism.
"Could it be…?"
Umino Yoru stared at the mirror-smooth surface of the boulder he had just sliced through, his reflection staring back at him. A sudden realization struck him.
"An intangible state of mind can influence reality… and conversely, the laws of reality can reshape the mind?"
This line of thought immediately led him to Yin-Yang Release, a concept he vaguely grasped but couldn't yet fully grasp.
From his past-life memories of the original series, Yin Release and Yang Release represented the creation and destruction of spirit and matter.
Yin Release was the power of the mind—shaping form from nothingness. The Susanoo of the Mangekyō Sharingan was a prime example, materializing chakra into armor and weapons—literally willing reality into existence. Yang Release was the power of the body—breathing life into form. Hashirama Senju's Wood Release, especially his Sage Art: True Several Thousand Hands, relied on Yang chakra to imbue wood with monstrous vitality, explaining why his techniques dwarfed Yamato's in scale and power.
As the Sage of Six Paths once said:
Yin Release — "Creation of Form from Void." Yang Release — "Bestowal of Life upon Form."
When combined, they became Yin-Yang Release, manipulating all creation—even rewriting reality itself. The Truth-Seeking Balls, formed from fused Yin-Yang chakra, could morph into weapons or shields and disintegrate matter on contact, embodying the duality of creation and destruction.
"So… spiritual energy and physical energy are the true essence of chakra."
The revelation sent a shock through Umino Yoru's entire being.
If that was the case, then his Transformation Technique and Ultrasonic Radar might not have been purely the result of scientific experimentation.
His strong mental energy—likely enhanced by his reincarnation—could have subconsciously tapped into Yin Release, allowing him to "create form from nothingness" and develop the radar.
Or perhaps, through repeated use of the technique, Yin Release had subtly amplified his progress, making development unnaturally smooth.
"The Mangekyō Sharingan is called the 'Eye that Reflects the Heart'… because it materializes the user's deepest desires or fears into reality."
A chill ran down his spine.
That was literal wish-fulfillment.
While the Mangekyō's abilities weren't consciously chosen, and awakening it required extreme trauma, it still showcased the terrifying potential of Yin Release.
"If I can harness this aspect of Yin Release… developing new jutsu would become exponentially easier."
The hardest part of jutsu creation wasn't the process itself—it was the uncertainty of whether it was even possible.
But with Yin Release's ability to 'create form from void', he now had a theoretical guarantee—so long as he had the resources and willpower, success was within reach.
Just as he was lost in thought, a massive disturbance erupted along the frontlines.
"Ebizō's retaliation… is here."
Umino Yoru's expression hardened as he reviewed the memories transmitted by his shadow clones.
"What?! This isn't just a squad—it's an entire battalion!"
Instead of the expected elite unit, hundreds of Suna shinobi were advancing—dozens of times larger than anticipated.
This wasn't just about revenge.
Sunagakure was launching a full-scale assault on the flank of Konoha's defense line.
Currently, Suna's main forces were concentrated in the Land of Rain, with only about a thousand shinobi stationed in the Land of Rivers.
This offensive alone accounted for nearly a third of their entire Riverfront garrison.
"RETREAT!"
Umino Yoru immediately fired a signal flare, ordering a full withdrawal.
Thankfully, he had prepared for this scenario.
The ten patrol squads under his command swiftly fell back, igniting pre-set forest fire barriers along the way.
While the flames wouldn't stop Suna's advance, they would slow them down—and the towering smoke would serve as a beacon for Konoha's main forces miles away.
Soon, Umino Yoru and his men regrouped at Shan Guiyao's defensive zone, a secondary fallback point.
After briefing the chūnin squad leaders, he dispatched a shadow clone to lead the retreat further back to a mountain pass—the third line of defense.
Meanwhile, the real Umino Yoru remained at the frontline with his summoned hawk, Shiro.
The inferno raged before him, but he knew it wouldn't hold Suna for long.
Ninjas could reshape the battlefield itself.
And these Suna forces wouldn't divert their attack—they would break through his sector, linking up with their main army to crush Konoha's flank.
Through the flames, Umino Yoru and his clones unleashed their Ultrasonic Radar, scanning the enemy's movements with precision.