First Battle of the Corpse and Trial of Inner Harmony

The shockwaves from the leak at Tobirama Senju's laboratory continued to ferment within the Uchiha clan. Panic and rage did not subside with time; instead, under the deliberate information control and hatred-stoking of the higher-ups, they transformed into a more oppressive and dangerous state of war readiness.

The physical condition of Izuna Uchiha had become an open secret. The sight of him coughing up blood and his increasingly failing eyesight left the clan in a state of agitation. Yet, he suppressed all voices of unrest with even harsher and more ruthless means. The deterrent power of his Mangekyo Sharingan remained formidable, though every time he used it, it felt as if he were burning away the last of his remaining light.

He worked almost without sleep or rest, handling clan affairs and poring over fragmented scrolls regarding forbidden arts collected from various places. His eyes were bloodshot, and his aura grew increasingly sinister. He knew that time was not on the side of the Uchiha. Before Tobirama Senju could perfect that blasphemous art, he had to find a way to counter it, or... fight to the death.

Friction along the border suddenly escalated. It was no longer small-scale reconnaissance and counter-reconnaissance, but targeted infiltration and sabotage operations led by elite Jonin. The Uchiha's goal was clear: at any cost, kill the researchers of the Senju clan, destroy any supply lines that might be used for forbidden art research, and even attempt to locate the possible site of Tobirama's laboratory.

The Senju clan, relying on the geographical advantage provided by the ever-expanding Forest of Senju created by Hashirama and the endless stream of new ninjutsu and tactics from Tobirama, launched a fierce counterattack. The intensity of the war reached a new peak after Uchiha Madara was severely wounded.

Uchiha Sou was also assigned to a patrol and assault squad. He maintained the "ordinary" Jonin performance of his Double Tomoe Sharingan, with exquisite Chakra control, solid Taijutsu, and calm tactical execution. He did not stand out in the heat of battle, simply fulfilling his duties reliably. He carefully hid the subtle changes brought about by "Inner Harmony" and focused more of his energy on observation.

He observed that the tactical style of the Senju clan was quietly changing. Their formations were more varied and their coordination more precise, often trading the smallest cost for the greatest casualties among the Uchiha. Behind this, it was clear that Tobirama Senju's tactical brain, calm to the point of coldness, was in command.

Even more unsettling was the appearance of some "special" Senju ninjas in several small-scale skirmishes. Their fighting style was fearless of death, even somewhat robotic; their recovery speed after being injured was abnormal, and their eyes occasionally revealed a hollowness inconsistent with a fanatical will to fight.

These signs sent a chill down the spines of the Uchiha high command—Tobirama Senju had likely already begun testing his immature forbidden arts in actual combat! Although there had not yet been a "true" Impure World Reincarnation body, certain low-end "puppets" or "enhanced warriors" based on corpses or captives seemed to have already been deployed to the battlefield.

This probing was like a dull knife cutting through flesh, constantly wearing down the nerves and vital strength of the Uchiha.

One day, the squad Uchiha Sou belonged to was ordered to rendezvous with a reconnaissance team retreating from enemy territory. The mission area was located in a hilly region with complex terrain.

When they arrived at the designated meeting point, they saw only the traces of a fierce battle and several corpses of Uchiha ninjas. The air was thick with the lingering, chilling fluctuations of Chakra, which felt extremely unsettling.

"We're late..." the squad leader's face was grim as his Sharingan scanned the surroundings vigilantly.

Suddenly, several Kunai shot out from the bushes on the flank with immense force and tricky angles!

"Ambush!"

The Uchiha squad scattered instantly, their Sharingan activating one after another to meet the Senju ninjas lunging from the forest. The battle erupted in an instant; Fire Style collided with Water Style, and Shuriken crossed with Kunai.

Uchiha Sou parried a fierce attack from a Senju ninja, his Double Tomoe Sharingan precisely capturing a subtle flaw in the opponent, and he followed through with a Kunai strike toward the enemy's throat. However, the Senju ninja did not dodge or evade; he simply tilted his head, took the blow squarely on his shoulder, and simultaneously threw a backhand punch hard toward Tsang's chest!

Trading injury for a kill?! Tsang was startled and immediately retreated, narrowly avoiding the blow. The Senju ninja's shoulder was drenched in blood, yet he seemed not to feel the pain, his eyes fanatical and hollow as he lunged again!

Something is wrong!

Tsang's Sharingan spun rapidly, observing his opponent. This enemy's Chakra flow was abnormal, seemingly forcibly stimulated by some external, chilling power. His muscle reactions were slightly stiff, but his strength and speed exceeded their normal levels.

It's one of Tobirama's test subjects!

Just then, a scream came from another part of the battlefield. An Uchiha member was being tightly entangled by two of these "fanatics." Although he had desperately inflicted heavy damage on one, he was pierced through the chest from behind by an Earth Spear from the other!

"Kenji!" The squad leader's eyes were bloodshot; he tried to rescue him but was blocked by his own opponent.

The Uchiha member named Kenji fell to the ground, blood gushing out, clearly beyond saving. Yet, the two heavily wounded "fanatics" wobbled to their feet, the flow of blood from their wounds seemingly slowing down, their eyes still hollow as they lunged again at the nearby Uchiha ninjas!

Fighting to the death without end!?

A chill and a surge of rage rose in the hearts of all the Uchiha members.

Uchiha Sou looked at the two "fanatics" lunging again, then glanced at his dying comrade on the ground and his teammates trapped in a bitter struggle. He knew he could no longer hide—at least, not completely.

He took a deep breath, his consciousness instantly sinking into the realm of "Weaving Logic," and the harmonious fluctuations of Inner Harmony flowed steadily within his body. At the same time, his Double Tomoe Sharingan locked onto the two charging "fanatics."

He no longer tried to analyze the flow of Chakra or muscle movement within them—that belonged to the realm of conventional combat. Instead, he focused all his spirit on the vague sense of "disharmony" brought by his Double Tomoe.

On those two "fanatics," he clearly "saw" a twisted and chilling sense of "disharmony" that was completely out of place with the surrounding environment and their own life force! That was the manifestation of the power of Tobirama's forbidden art!

Now!

Tsang did not attempt to attack their bodies; instead, he projected the trace of Inner Harmony condensed by his "Weaving Logic"—the steady intent of "life"—through the gaze of his Sharingan, like an invisible ripple, slamming it toward the two "fanatics"!

This was not an attack, but more like... interference? Or rather, an attempt to use his own "harmony" to collide with their "disharmony"!

The effect was not earth-shattering.

The two "fanatics" who were charging madly suddenly stalled! It was as if a tiny grain of sand had suddenly been mixed into a precision-running gear; their movements experienced an extremely brief, almost imperceptible stutter and lack of coordination! The hollow fanaticism in their eyes also seemed to flicker, revealing a trace of extremely faint confusion!

This process lasted less than a second!

But for elite ninjas locked in a life-and-death struggle, this momentary flaw was enough!

An Uchiha member fighting another Senju ninja nearby, though not understanding why, let his combat instinct seize this fleeting opportunity! His Kunai precisely slashed across the throat of one of the "fanatics"!

Another teammate also took the opportunity to break free from his opponent, and his ninjutsu slammed into the other "fanatic"!

The two "fanatics" staggered backward. This time, their wounds did not show that abnormal sign of recovery; the hollow fanaticism in their eyes dissipated rapidly, replaced by the pain of life fading and a trace of relief, before they collapsed heavily and died completely.

The battle ended quickly. The remaining Senju ninjas, seeing their test subjects broken, retreated rapidly.

The Uchiha squad paid the price of two members severely wounded and one sacrificed.

The members gathered around their fallen comrade, the atmosphere heavy. The squad leader walked over to Tsang, patted his shoulder, and looked at him with complex eyes: "That was... well done just now. Did you see the weakness of those monsters?"

Tsang breathed slightly, sweat seeping from his forehead—the "mental interference" just now had consumed far more of his spirit than a fierce battle. He shook his head and said with feigned exhaustion: "I'm not sure... I just felt their Chakra was very chaotic and tried to use Genjutsu to interfere with it; it seemed to have some effect... It might be a flaw in Tobirama's technique."

This explanation was reasonable. It was common knowledge that the Sharingan's Genjutsu could interfere with the flow of Chakra. The squad leader nodded without digging deeper, merely sighing: "It's fortunate that it worked... otherwise, the losses today would have been even greater. That bastard Tobirama, how many of these ghost things has he created..."

Tsang lowered his head in silence, masking the shock and contemplation in his eyes.

It worked... although it was extremely faint, my "Inner Harmony" intent could indeed interfere with that "disharmonious" forbidden power!

Even though it only caused them to stall for an instant, far from being a purification or a breakthrough, it proved that his direction was not wrong!

However, the joy of success was quickly replaced by worry. This time it was luck, but what about next time? Tobirama's technique would surely continue to be perfected; the next ones they encountered might not be these low-end "fanatics," but something closer to a true "Impure World Reincarnation body."

By then, would his weak interference still be effective?

Furthermore, would frequent use of this ability draw the attention of the world? For a fleeting moment just now, he seemed to sense that faint, lingering feeling of stagnation in his surroundings once more; although it was far less intense than when he had previously attempted to intervene in the fate of Izuna, it was undeniably present.

Risk and opportunity coexist.

He glanced at the corpses of his fallen comrades, then looked toward the direction of the Senju clan grounds.

The path of seeking within is paved with thorns. Yet he must continue, seeking a glimmer of survival in his own way upon this battlefield where the dead have only just begun to appear.

He needed a more powerful "Inner Harmony," and even more so... a strength that truly belonged to him.

Deep within those Double Tomoe Sharingan, the vague intuition regarding a higher level of power seemed to have become slightly clearer. But that door remained tightly shut, still far out of reach.

The battle had ended, but the true trial had only just begun.