The subterranean laboratory was bathed in the harsh, sterile glare of overhead surgical lights. The oppressive scent of antiseptic and cold iron permeated the freezing air.
Strapped securely to a heavy metal operating table in the center of the room, Saku Hyuga groaned.
Through a hazy, localized fog of pain, Saku slowly forced his eyes open. His skull throbbed a vicious, rhythmic tempo, the lingering aftermath of the blunt-force trauma. He instinctively tried to reach up to massage his temples, only to discover his wrists and ankles were bound immovably by thick leather restraints reinforced with chakra-suppressing steel.
Panic spiked in his chest. He thrashed against the bindings, the metal table rattling loudly in the quiet room.
As his vision cleared, he registered Haru's silhouette standing near the edge of the light.
"Haru!" Saku gasped, his face twisting into a portrait of absolute, desperate confusion. "Haru, what is the meaning of this?! Why are you doing this?!"
Haru remained perfectly still. She stared down at the restrained servant, her pale eyes devoid of a single ounce of warmth or empathy. She did not even dignify his frantic questioning with a response.
From the shadows just beyond the surgical table, Kei's clinical, unhurried voice drifted into the light.
"I highly advise you to cease your struggling, Saku. Pointless physical resistance will only elevate your heart rate and compound your agonizing reality."
If Saku had offered a different answer during their conversation by the river—if he had displayed even a microscopic fraction of loyalty to his own subjugated bloodline—Kei might have reconsidered his selection. He might have hunted down a different target.
But Saku was a completely irredeemable sycophant. He was a class traitor who gleefully utilized the Main House's whip to bleed his own kin. In Kei's ruthless calculation, Saku was functionally indistinguishable from Great Elder Taihiro. Therefore, Kei harbored absolutely zero moral qualms about utilizing him as biological scrap.
Kei had abandoned the luxury of a pristine conscience the moment he resolved to break his cage.
"Haru, why?!" Saku ignored the doctor entirely, straining his neck, the veins bulging in his eyes as he glared at the kunoichi. He was drowning in a suffocating cocktail of denial and betrayal. "This man is a blind cripple! How could you possibly choose a useless civilian over me?! We are the elites! We were meant for each other!"
His frantic, pathetic screaming echoed off the stone walls, but Haru remained a statue of cold indifference.
The absolute silence finally forced Saku to confront his horrifying reality. He was not a respected elite. He was not Taihiro's valued proxy. To the woman he obsessed over, he was nothing but a clown.
"Do you honestly believe you have won, Hyuga Kei?" Saku spat, violently shifting his rage toward the blind doctor. "I am Lord Taihiro's personal servant! If you dare to damage me, the Great Elder will subject you to a thousand deaths! He will burn the Caged Bird Seal into your brain until you beg for the grave!"
"You will not live long enough to witness my execution," Kei replied, his tone perfectly flat. "And Taihiro will never be granted the opportunity to enact it."
Wasting no further syllables on the condemned man, Kei stepped up to the head of the operating table. He reached out, resting his index and middle fingers lightly against the center of Saku's forehead, directly over the hidden curse mark.
It was time to systematically verify Orochimaru's Phase I clinical data.
Saku thrashed violently, screaming obscenities, but the heavy restraints held him perfectly immobile.
Kei focused his mind, channeling a microscopic, highly controlled thread of chakra from his fingertips directly into Saku's skin.
Through his hyper-evolved empathic perception, Kei 'watched' his chakra infiltrate the boy's neural network. Almost immediately, he encountered the perimeter of a highly complex, aggressive energetic matrix. The outer boundaries of the Caged Bird Seal were layered with dense, interlocking defensive barriers, specifically engineered to repel foreign chakra.
Maintaining absolute, surgical precision, Kei bypassed the initial barriers, pushing his chakra deeper into the matrix. As he breached the first layer, he perceived the true architecture of the curse: a tightly woven, suffocating net of red energetic nodes, all pulsing with dormant, lethal intent.
Kei abruptly halted his probe. He maintained his chakra presence just outside the core matrix, carefully monitoring Saku's physiological response.
Saku was panting heavily from exertion, but he was not experiencing localized cranial pain, nor was his brain spontaneously incinerating.
"Fascinating," Kei murmured, a genuine note of scientific satisfaction in his voice.
Standing nearby, Haru closely observed the monitor readings. "So, Orochimaru's baseline data is accurate? Probing the absolute outermost perimeter of the Caged Bird Seal with foreign chakra does not instantly trigger the lethal self-destruct protocol?"
"That appears to be the reality," Kei nodded slowly. "I calculate that when the Main House elders conduct their monthly 'inspections' of my seal, they halt their chakra penetration at this exact perimeter depth."
"The outer boundary of the seal is lined with a highly sensitive network of energetic tripwires," Kei deduced, analyzing the red nodes. "These connection points act as a localized security perimeter. They are designed to trigger pain compliance before the core matrix is ever breached."
"As for whether they truly trigger the agonizing symptoms described in the Sannin's logs... let us verify."
Without another word, Kei pushed his chakra forward a fraction of a millimeter. He deliberately brushed his energy against one of the red connection nodes.
The instant the foreign chakra made contact with the tripwire, a blood-curdling, inhuman shriek erupted from Saku's throat.
Even without his sight, Kei could vividly perceive the catastrophic spike in Saku's pain receptors. The servant's body convulsed violently against the leather straps. His face drained of all color, turning a sickly, deathly pale as he experienced the sensation of his skull being slowly, methodically split open from the inside.
"Flawless engineering," Kei noted clinically, entirely unmoved by the screaming. "The perimeter nodes operate exactly as a defensive encirclement. Contact triggers an immediate, localized pain-compliance activation without engaging the lethal incineration protocol."
Kei did not push his chakra into the core. Instead, he systematically dragged his energy across several other peripheral nodes, mapping the exact boundaries of the pain threshold.
With every microscopic touch, Saku's head throbbed with mind-shattering agony.
"I will... I will kill you! I swear to God, I will skin you alive!" Saku shrieked hysterically, his vocal cords tearing from the sheer volume of his screams. "Either you murder me right now, or I will ensure you die screaming!"
"Do not concern yourself with vengeance, Saku," Kei replied, his voice a soothing, terrifyingly calm murmur amidst the chaos. "I assure you, the moment my diagnostic mapping is complete, your biological functions will cease."
"Although you view your own bloodline as a humiliating stain, and despite the fact that you gleefully act as the Main House's attack dog... I am a merciful physician. I will grant you a swift, painless termination in your final moments."
Saku's face contorted into a grotesque mask of agony and fanatical indoctrination. "Taihiro-sama will never let you escape! The clan will hunt you to the ends of the earth!"
"You think you can break the Caged Bird through me?!" Saku spat blood onto the surgical table. "It is impossible! You will never succeed! The Caged Bird is a sacred blessing bestowed upon us by the ancestors! A filthy, crippled traitor like you will never—!"
Kei silenced the fanatic by brushing two nodes simultaneously. Saku's eyes rolled back in his head, his spine arching off the metal table as a fresh wave of blinding agony severed his vocal cords' ability to form words.
Kei withdrew his fingers, stepping back from the table.
"Haru," Kei commanded smoothly. "Your turn. Execute a peripheral probe."
Without a single fraction of hesitation, Haru stepped forward. She raised her hand, her fingertips glowing with pale blue chakra, and reached toward Saku's forehead.
Through the haze of his agony, Saku saw the woman he obsessed over calmly preparing to torture him.
His mind completely, violently snapped.
The excruciating physical pain inflicted by the Caged Bird Seal paled in comparison to the absolute, soul-crushing despair of Haru's betrayal. The realization that she was a willing, active participant in his agonizing execution shattered the very foundation of his pathetic reality. Saku's eyes glazed over, becoming entirely hollow and lifeless. He didn't even scream when her chakra made contact.
Simultaneously, a crisp, mechanical chime echoed in the silent theater of Kei's mind.
[Psychological treatment concluded. The patient's psyche has suffered a catastrophic, irrecoverable collapse due to the subject 'Haru Hyuga's' operational choice. Psychological perturbation level: Exceeded expectations.]
[Based on the clinical treatment results, you have acquired: Gentle Fist Mastery.]
[Note: A comprehensive integration of Special Jonin Saku Hyuga's complete martial understanding of the Gentle Fist, including advanced proficiencies in the Eight Trigrams Palms and the Eight Trigrams Vacuum Palm (Air Palm). Integrating this data will drastically elevate your baseline Gentle Fist lethality.]
Kei was not surprised by Saku's psychological disintegration, nor did he feel a single shred of clinical sympathy. Saku had chosen his collar. He had chosen to be a monster to his own people.
Furthermore, the acquisition of Saku's martial data was merely the first installment of interest Kei intended to collect from the Main House. He had promised himself he would systematically dismantle Great Elder Taihiro's empire, and he always honored his debts.
Watching the horrific, clinical dismantling of a human mind, Shisui Uchiha finally stepped out of the shadows. His scarred face was pale, his jaw locked tight.
"Are you absolutely certain this butchery will actually grant you your freedom?" Shisui asked, his voice rough.
"I cannot offer a certain guarantee," Kei shook his head slowly. "But I must attempt the surgery. Otherwise, I will be a slave to this brand until the day I die."
"I understand," Shisui said, letting out a heavy, conflicted sigh. He hesitated for a long moment before crossing his arms over his chest. "If you require physical assistance during the extraction phase... call on me."
Before Kei could thank him, Shisui quickly masked his moral compromise with cold pragmatism. "Do not over-analyze my motives, Hyuga Kei. I am doing this entirely for my own survival. My clan's future is currently tethered to your intellect. If you detonate your own brain tonight, I wouldn't shed a single tear."
Kei smiled warmly, turning his bandaged face toward the Uchiha. "Do not worry, Shisui. I promise I won't overthink your glowing endorsement."
Shisui scowled, instantly annoyed by the doctor's unflappable demeanor.
Before he could retort, Saku let out one final, agonizing whimper as Haru completed her diagnostic probe. The servant's neural pathways finally overloaded, and he plunged into the merciful blackness of total unconsciousness.
The baseline data was confirmed. The perimeter was non-lethal.
Kei turned his back on the broken servant and walked purposefully toward the second metal operating table prepared nearby. He climbed onto the cold steel, lying flat on his back, staring up at the blinding surgical lights with sightless eyes.
It was time to empirically verify the architecture of his own soul.