Whoohoo, this plot bunny hit me hard. A take on the eye transplant and fight afterwards, in Kakashi Gaiden. I don't know why this hasn't been done before. To all my Kashi-sensei fans, a treat for you here. Written on special request from a friend. Prepare for blood and angst.

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With first light dawns clarity.

Lightning and steel;

But to me, my friend,

Before these first came agony.

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"I give you my eye."

In this moment of silence, Kakashi's world is divided in clear-cut lines.

His left eye sees nothing but a void. His right eye draws in light from the world, drowning in it, pouring it down his breathless throat to rend his heart asunder. Pain saws him in half, a searing line of white fire down from the top of his skull to the soles of his feet. He is grateful – or perhaps not – that his right eye is still fully functional to see just how gruesome the sight of Obito's crushed right side is.

The agony is clear, too. It burns like rejuvenating flames through his numbed nerves from the moment Obito speaks; all Kakashi's hatred and his bitterness reversed in one awful moment and slashed into his very soul like tanto to gut. Honour to shame. Rival to friend.

Sight and blindness reversed in a terrible paradox.

Kakashi feels himself detach from awareness, turning inward, and his emotions are laid out before him like dreamsand in a glass box, vulnerable, exposed – and hairline cracks are already spreading like gossamer threads of emptiness. His lips move, but sound eludes him. He does not hear, but rather senses his howl of denial echo within the prison of his mind.

"Kakashi. Kakashi!" The voice scythes into his throbbing consciousness like scalpel to raw wound.

Kakashi raises his head from his hands; he does not remember lowering it in the first place. "Rin," he mouths hoarsely. The concerned gaze of his teammate resolves itself in his one-sided vision. She seems paler, like the world around her; bleached of colour and of blood. Is his eyesight failing?

Or maybe it is the world that has failed him.

Rin's lips are moving. "Kakashi. I have to operate immediately. Come over here."

As Kakashi shuffles forward on his knees, the cold, logical part of his mind – the part trained to react to any situation with ruthless analysis – hears how Rin's voice falters over a swallowed sob, knows she is clinging to the calm authority of a medic-nin, reads the tremble her hand as it clutches Obito's and calculates the approximate duration of Obito's remaining life by the trickle of blood down his chin and the leaking of his chakra into the air–

Rin is right, after all. She would have to operate soon, and quickly.

The granite beneath his shoulder blades is warm with the chakra that had washed over it from the fray minutes before. He lies supine, nerveless, by his newfound friend's side, barely aware when Rin places Obito's hand in his. The other boy's fingers are limp; Kakashi does not dare to turn his head to his right, where he knows Obito's half-crushed face will stare at him.

"Hold his hand," Rin says. "I'll need both of mine free for this." She pulls down his mask without preamble. Kakashi shivers as cold air rushes over his face. Rustling sounds behind Kakashi's head; then silence as her fingers still.

"What… what is it, Rin?" Obito whispers. Kakashi swallows at the weakness of those words, and the smile that can still be heard there.

"There isn't… there isn't enough anaesthetic," Rin says blankly. The tremor in her voice grows stronger – another horror to add to the current situation. "They took my medkit, so I have to use the one I gave to you, Kakashi. But…it's a personal medkit, so there's only enough for one of you to have localised anaesthesia."

"Give it to Obito–"

"Kakashi needs it more–"

Both voices grind to a halt, one from exhaustion and the other from emotional drain. In the ensuing silence, Kakashi clamps down on the churning in his stomach and turns his head to the side. The sight is not quite so bad as he expected; from this angle, Obito seems normal. It fact, if it were not for his slow, laboured breaths and the slow slide of his single sharingan to meet Kakashi's gaze, Obito appears perfectly unharmed.

They stare at each other for a long moment, equals, separated by a chasm of mortality and mutual pain, joined by slack hands, face to face. No mask or goggles to hide behind now.

Then Kakashi exhales carefully, turning back to the sliver of through the rock above. "Give it to Obito. I can't have the anaesthesia dulling my reflexes when I go out there and wipe the floor with that filth." His eyelid lowers over his pupil in a slow blink. Moisture blurs that unreachable azure above.

A burble that should have been a chuckle; Obito's fingers twitch in his.

Kakashi senses Rin's hand pass over his head, and Obito's next ragged breath is an softer one of slow release. The anaesthesia must be dulling some of the nerves around the injury in his head, too.

"Kashi-kun. Bite on this." The only sign of Rin's increased distress is her use of Kakashi's nickname. Only Minato-sensei would ever call Kakashi Kashi-kun. Kakashi fights against the swell of longing in his chest. Minato-sensei should have been here. If he were, he could somehow… fix…everything.

Something smooth and cold and solid slides between his teeth. A kunai. Its dull grey metal tastes of bitter iron, coal-fired forge, and the lives it has taken and will take, silky and unyielding over the roughness of his tongue. Kakashi clamps the weapon tightly in his jaw, not caring how the pressure spikes the nerves in his molars. This is paltry in comparison to what is to come.

Rin's swallow is an audible gulp of determination. "I'm starting now."

Kakashi closes his right eye.

Then the pain slices him into fetters of shadow.

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The first cut is always the worst.

Agony cleaves his skull apart; he knows his brains must be spilling out onto the granite, the gorge heaving in his stomach, his nerves short-circuiting in an awful torrent of fire that burns his tongue and heats the metal red-hot against his lips. The taste of bitter iron floods his mouth; it might be his own blood, bile, or tears, but he does not know and cannot know for his skin is torn and blood and cerebrospinal fluid and menigal mucus must be pouring out of every orifice and oh no oh no there's something stabbing into his mind and–

"Kashi! Kakashi! You've got to stay still! I nearly cut into the lacrimal fold–"

Oh. Rin.

And Kakashi. His name.

Kakashi stills his limbs by a sheer force of will, tremors wracking his frame as he claws at the rough sandstone under his fingers. A few nails snap off, but he nearly laughs at the sensation; it is almost pleasurable compared to what scythes through his head.

Rin's scalpel works around the base of his eye, and severs the optic nerve with a single clean cut that shatters his mind in a maelstrom of mirrored ice, each crystal a memory clawed clean from its prison cell and thrown before his helpess, lidless sight, so the shadowed depths of his non-vision becomes a terrifying swirl of reaccuring nightmares.

Hatake Sakumo lies gutted before him, again and again, the stench of his father's blood in Kakashi's nostrils – some small part of him realises it might be his own blood this time – and he drowns in the crimson pool, his father's dead eyes staring back at him like the glassy marbles that rolled across the wooden floorboards when he still knew what fun meant, the kunai shattering between his teeth, the new one Rin thrusts in his mouth smeared with both his and Obito's scarlet life-liquid, causing him to gag–

And then Rin is screaming something at him and pushing a wad of bandage at his shaking fingers and he complies on autopilot, dabbing at the hollow in his skull as Rin struggles with forceps and healing chakra in both hands–

And Kakashi becomes aware that he is sobbing, and that his right hand grips Obito's slack palm so hard that he knows he must be causing minute fractures, and he tries to loosen his crushing grip but somehow can't and he feels so sorry so so sorry for causing Rin and Obito pain and being even less than trash and not caring for his nakama and caring only for the mission and dishonouring his father's memory and–

"Ka..ka..shi…"

Obito's voice strikes Kakashi like a bolt of lightning to paralysed limbs.

The humour is still there, in that once-loud voice that thins to a whisper. "Breathe…baka. It'll work." Cold fingers twitch within Kakashi's palm.

Kakashi's first breath is a heave of sweet air that burns its way down his lungs in a cleansing torrent of pain; a good pain. He had not been aware he had stopped breathing, but Rin's choked mumble of relief tells him otherwise, even as she slots something unmistakably foreign into his eye socket, like a ill-fitted light-bulb sparking as it finds contact within a lamp socket intended for another source of luminance, another truth, another future.

Then the healing begins.

The cessation of pain is so sudden that Kakashi gasps at the emptiness it leaves behind, like the needling sensation of skin that is exposed to heat too quickly after being half-frozen.

Rin is precise, quick; healing chakra connects ligaments, tendons, muscles, tear ducts, repairs the optic nerve, seals the wound from eyebrow to cheekbone into a single ridge of hardened scar tissue. Medical ninjutsu is brilliant, impossible; the optic nerve is of the central nervous system and should not be able to repair itself, but axons and sheaths spread like the wandering roots of a new sapling, healthy, unbroken. Water from a canteen splashes over his face, rinsing away fluids and tears. His mask sticks to his wet skin as it is raised over his features again.

"It's done." Rin's voice is a half-sob of exhaustion, emotional walls crumbling.

Obito's breath is a shallow sucking in of air. "Ha ha… told you it could be done."

Kakashi's right eye flicks open. He does not quite think he is willing to open his left one yet. Obito's hand, he places in Rin's. Opening his mouth to release the kunai, he spits several times to clear his tongue of the taste of iron. He isn't quite successful, but that hardly bothers him anymore. He fights the urge to swallow; nausea sways him as he clambers to his feet.

"Wait for me," he croaks softly, bracing his weight against a boulder. "I'll come back for you. Both of you."

He senses Obito smile his broken half-smile, an imitation of that once wide-mouthed grin.

"Take care of Rin."

He faces the light. "Yes."

And then the sky rushes down to meet him, and the wind ruffles his sweat-slick hair as he emerges into clean air.

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The first influx of light nearly blinds him.

Kakashi sees everything at once – a hummingbird's wing slows to a throb of emerald and scarlet in the bushes to his right; ley-lines of natural chakra thrum over the ground below his feet; his own arm is a spiderweb of channels, a network of rivers flowing with the chakra pulsing from each beat of his heart, lining his nerves and pressure points. And he can see chakra-laced blood flow through the only other heart in the clearing – that of his target.

It won't flow for much longer.

His leap off the mountain of rubble tears a rift in time.

The enemy nin sucks in a breath, chakra flaring in his arms as he sends kunai and shuriken swarming towards Kakashi in a maelstrom of metal.

To Kakashi, each shuriken is a dull grey snowflake, sharp edges catching the late afternoon sun, the kunai icicles of mirrored glass, all floating in the turgid currents of time like debris in a slow-moving channel. His fingers find the grip of his tanto and tighten on the wrapped hilt – he has all the time in the world – and the sound of his heart becomes a drumbeat that reverberates through the air.

Exquisite clarity.

Snowflake and icicle alike melt in the roaring heat of his fury. White fire wreathes the blade of his father's tanto – a white fang snarling in the tunnel of focused light between Kakashi and his enemy. And when tanto meets kunai, and the precious Hatake blade shatters in single, pure note of farewell, Kakashi listens to the music, sees the scarlet and sable of his new eye reflected in those dancing shards, and says farewell to his old self.

Hatake Kakashi, son of the White Fang, dies with his father's blade, and in his place rises Hatake Kakashi of the Sharingan.

Lightning pours down his arm in a swell of incandescent power, and his eye – his sharingan – watches the fire surge through his chakra lines and into his handseals, observes it crackle over his fingertips and palm in a molten sphere of skyfire, and follows the chakra as it plunges into the other nin's abdomen, flaring those foreign lines in searing, burning overload.

The enemy nin does not die from a lack of life, so to speak; he dies from an overload of energy that shatters his nerves and liquefies his chakra lines.

The broken blade of the tanto embeds itself in rock with a solid thunk as Kakashi's other hand finds the ground, reversing his momentum in a smooth arc to land silently in the dappled shadow of an arching root.

The body of the jounin does not make a sound as it crumples to the ground, close to the lip of the rubble.

Kakashi holds his position for a moment longer, adrenaline pouring through his system, until the rumble of shifting rocks catches his attention. Reinforcements. He has to bodily drag Rin away from Obito, letting her screams of desperation break against empty ears.

Granite forms his friend's cairn. Obito's last words are his, and his alone.

"Rin."

Chakra exhaustion overwhelms Kakashi, blurring the world into a haze of pain. His sharingan registers dully that chakra signatures are approaching, but he does not know…he cannot know…he doesn't… He barely acknowledges what Rin says to him, and what he says in return, what it might mea –

In those last, clear seconds, Kakashi takes Minato-sensei's kunai from his weapons pouch, letting it fly–

And in that empty moment between awareness and unconsciousness, Kakashi sees a flare of familiar chakra to his left…

Then there is nothing at all.

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Minato didn't need to say anything when Kakashi woke. He seemed to understand.

Kakashi still isn't sure if he does, himself.

Rin does not speak, either.

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Kakashi stands vigil in front of the memorial stone.

Absently, one hand reaches up to rub at the headband over his eye. It aches dully; it always will. Some small part of him will always be buried back by the Kanabi Bridge. And behind his closed eyelid, he sees not a blank expanse of black, but every moment of that last battle, remembered down to the last leaf whirling in the wind of his passage.

The metal of his glove clinks as it meets the buckles on his jounin vest. Sometimes he regrets putting aside his old clothing, but he wants no reminders of his past self.

"Hey, Obito," he murmurs softly through the fabric of his mask. "Kushina-san's pregnant. If…if you don't mind, I'd like to give your goggles to the kid. If you don't mind."

The wind stirs the grass by his feet, sends a whirl of early autumn leaves dancing over the blades, but gives no answer.

Kakashi turns back towards his village, his vision clear, and his footsteps sure. He has a mission to return to. The sunset sets the sky afire with crimson and gold. Obito would have loved this; and so would Rin.

Under the covering of dark blue cloth, the sharingan that has come to define him whirls on, a gift, a memory, and a pathway to his future.

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End

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What did you all think? Drop me a review if you have anything to say. I love Kakashi, I really do.