NADESHIKO ISLAND
"Don't bother," Tobirama said calmly to the Uchiha spawn. "We are no longer in the Land of Wind."
Eerily enough, the chunin simply glanced up at him, seemingly unconcerned about being captured and separated from the rest of his team. Tobirama subconsciously shifted his gaze to avoid directly meeting the boy's crimson ones, instead focusing on his pale cheeks below; decades of battling against the accursed Uchiha had engrained this instinct too deeply in his psyche for him to forget even after death.
For to adapt is to survive after all.
The Uchiha had forced him to adapt.
"Any last words, Sasuke?" Tobirama asked the child as he formed a chakra scalpel in his free hand. It was the least he could do before ending the boy's existence. Surely, it was unfortunate a prodigious shinobi this young had to die under such circumstances, but the Second Hokage was not about to risk the future of his brother's heritage out of mere sentimentality.
In response to his question, the young Uchiha simply shrugged, appearing nonchalant in the face of his imminent demise. The boy made no overt moves to escape from his imprisonment.
Suspicious.
Tobirama sighed, discarding the passing thought of dispelling the restraining technique that held the boy before killing him. He would rather not risk things getting any more complicated than they ought to be. His arm blurred forward, punching through the water sphere towards the boy's chest. The chakra scalpel squirming within Tobirama's palm pierced Sasuke's heart, clouding the water sphere that imprisoned him crimson with blood.
Tobirama blinked as he stared at his severed arm floating within the bloody sphere of water. The scheming child stared back at him defiantly, his left hand deathly pale as it tightly gripped the Tanto with which he struck him. The Hokage withdrew what was left of his arm, staring at it with unbridled curiosity.
"...What sort of boundless hatred would drive a child to concoct a poison as sinister as this?" Tobirama asked as he examined the wicked bane smeared on his severed arm. His gaze flickered towards the envenomed blade in the boy's hand. It was at that moment a discomforting thought surfaced in his mind.
Had I been truly alive, this boy, still wet behind the ears, would have killed me…
"...All things considered, that was an outstanding attempt at mutual murder, Uchiha Sasuke," Tobirama mused, "Colour me impressed." The Hokage was starting to see what had his student so worked up. This Uchiha boy would surely have grown to become a true menace had he been left to his devices.
Tobirama shook his head in disappointment. Had the boy been born Senju, or at least, truly loyal to the leaf, Konoha's future would have at the very least been significantly more secure. But, alas, he was not.
What a waste…
The Senju sighed as he let the Water Prison Jutsu dispel, the dense, crimson liquid splashing on the beach sand as it deposited the boy's limp corpse on the floor. He bent over, reaching to pluck the Uchiha's Dōjutsu from his cooling cadaver when a poisoned blade stabbed him through the face.
Tobirama blinked again as his split porcelain mask slowly fell away to reveal his gobsmacked expression. The Hokage didn't dare look down; as in the periphery of his vision, he sensed two crimson orbs staring at him, goading him to peer into their infernal depths.
Taunting him.
Tobirama's arm blurred, aiming to obliterate the bones in the Uchiha's sole functioning arm. The counterattack tore through with ease—excessive ease—seemingly phasing through its target.
An afterimage.
The Hokage looked up at the child who, for the second time today, had succeeded in landing a lethal attack on his person. True, he was nowhere near his peak strength given the shoddy reincarnation his student performed to bring him back, but still. Twice?
It was starting to get embarrassing.
Tobirama stared at the Uchiha standing across from him, causally restarting his heart. Although the organ was located several inches away from the position expected in any normal human—beneath the right lung of all things—the Hokage could still easily tell what it was. Life returned to the boy's aura and the mask of death slowly slid off. The inch-long gash in his chest remained open, but the blood flow had clearly stopped.
For all intents and purposes, the boy was mostly unharmed.
"Lord Second," the Uchiha said, speaking for the second time since their admittedly violent interaction began. "And to what do I owe this honour?"
Tobirama squinted suspiciously. The scheming child was clearly trying to buy time., but unfortunately for him, he had no intention of letting him do so.
A barrage of kunai shot from Tobirama's grasp.
Sasuke caught one, dodging the rest.
Tobirama pulled on the captured projectile with his intent and appeared in front of the boy, his fist shooting towards his skull.
Sasuke's chakra churned, cold and aberrant, and the inert network of barrier tags that lay hidden beneath the loose beach sand in front of him suddenly flared to life with a blinding intensity. A forest of animated kanji sprung out of the dirt beneath Tobirama, attempting to latch onto his body and seal him away.
Tobirama pulled on one of the still airborne projectiles behind the boy, reappearing a few meters away, dodging the trap. Before his feet even touched the ground, another barrage of kunai shot from his grasp towards the boy's back. The mass of projectiles struck home and Sasuke exploded in a puff of white smoke.
A Shadow Clone.
Tobirama paused his, eyes flickering erratically in search of the missing child. He sensed a fist shooting towards his skull from behind, leaning forward to let it sail over his head. His right hand shot out to catch the boy's left ankle.
Sasuke responded by locking the offending arm in a tackle with his other feet before retaliating with a palm strike to the face. Tobirama caught the counterattack with his other hand, neutralising it.
Tobirama smiled as he held the boy's entire body weight in both his arms. He heaved in preparation to brutally bodyslam him into the floor. The boy smiled as well, an expression that significantly confused the Kage.
"Lend me a hand, would you, Hokage-sama," Sasuke said, forcibly puppeteering Tobirama's left hand to weave a series of hand signs with his sole functioning one. The boy's body suddenly turned soft, his bones disjointed, allowing him to slip out of Tobirama's hold before leaping away using the larger man's chest as a kickboard.
Airborne, Sasuke turned to face his foe, inhaling deeply before exhaling a literal sea of flames.
"Fire Release: Great Fire Annihilation!"
Tobirama's hand blurred through a series of seals before he too inhaled, gathering chakra in his core.
"Water Release: Exploding Water Colliding Wave!"
A great volume of water spewed forth from the Hokage's mouth, advancing as a torrential surge towards the incoming sea of flames. The two masses collided explosively to release another mass of superheated steam that irreversibly altered the surrounding ecosystem.
Tobirama stood vigilantly as the resultant tempest whipped coarse beach sand violently into his grey, lifeless eyes. He surveyed the damage wrought on the beach by both their techniques and came to a resolute conclusion.
Uchiha Sasuke must not be allowed to leave this place alive!
His intent heaved, teleporting him to the technique formula he placed on the child just moments ago during their impromptu grapple.
The Uchiha was waiting for him.
Tobirama's gaze panned down to the mass of shadows attached to his own. He made sure it stayed there. Sasuke tried to force him to gaze into his eyes. Tobirama grunted as he resisted. Defiant. He tried to dispel the restraining technique with raw power, but the boy held fast. Unyielding.
No matter, The Kage shrugged internally as he pulled on his chakra pool, he is close enough.
"Mutually Multiplying Explosive Tags!"
For a moment, everything went still. In that same moment, grim realisation dawned on Sasuke; even without seeing his expression, it was glaringly obvious from how frantically he tried to flee the scene.
It was too late though.
His fate was already set in stone.
*BOOM!*
…
.
.
.
…Tobirama reformed eyes blinked open.
He forced his reformed upper half, resting against the curvature of the crater he now found himself in to sit up. Acrid smoke and dust swirled chaotically in the air. The dirt beneath smouldered, crackling noisily as it slowly cooled from its superheated state.
Surely, the boy is dead now?
The micro-debris suspended in the air slowly cleared to reveal an ephemeral silhouette towering in the distance. Four skeletal wings extended from its back, curling over the shoulders and two more laid curled on the chest. Six skeletal arms extended from the torso, four of which rested on the floor palm first. The other two languidly stretched out to the side. And crowning this abomination were three fused heads; each distinctive in its own way. The first was a simple human skull with three pairs of skeletal wings extending from where the ears ought to be and curling regally around the head like a crown. The second had a flat, featureless face—like a board—with six darkened magatamas carved into it.
The third was…
Incomprehensible.
Tobirama felt his very soul hurt the longer he stared at it. He looked away, the name of the incomplete technique rising, unbidden, in his mind.
Susanoo…
Yūbu no Aragami
The Tempestuous God of Valour
His gaze descended to focus on the Uchiha within. The boy knelt beneath the protective umbrella of his technique, his left side, including a portion of his face, as well as a significant portion of his kimono, horribly burnt away.
"You shouldn't have done that, Tobirama," the… thing said hoarsely as it glared malevolently at the Tobirama.
In response, the Kage pulled with his intent, letting his technique drag him back to Konoha. Hiruzen stood abruptly, staring at him in shock, but he ignored him. The Second Hokage's eyes were frantic, a hint of horror hidden within them.
There was no doubt in his mind that had he stayed a moment longer his very soul would have the rest of all eternity to bemoan his foolishness.