Author's Note: This does have a stretch bordering on a deus ex machina, but, to be fair, that's true of a lot of canon incidents involving the post-timeskip Sharingan anyway.

Obito and Rin make it out of the cave-in.

Kakashi doesn't.

Any ninja would say it was a horrible trade. Two lesser chuunin saved for one prodigious jonin - it's a disaster.

But, for the moment, they aren't ninja. They are two terrified children, and, though grieving for their teammate, they are desperately glad to be alive.

The next months push them hard.

Obito was a mediocrity, at least by the standards of his clan, but a Sharingan user must live up to the standard of his ability. A ninja could go very far, copying techniques. He even earned grudging praise from his fellow ninja.

But even in their praise was an undercurrent of resignation, of Kakashi could have done better.

Kakashi wouldn't need others' techniques.

Kakashi was the ninja we needed.

And the nightmares go further: they show him the boulder again and again, the obstacle he was too slow to divert, and say-

It should have been you instead.

Rin has no such troubles, of course, though she grieves. (The dreams whisper to him about that, too: Do you really think she'd weep so much, if it had been you?) Konoha needs every medic it has. She barely has time even to grieve, much less fuss over survivor's guilt.

Obito envies her, a little. The grinding repetition of it should have been you seems always to linger at the back of his mind, filling the empty space in his thoughts even when his head is full of techniques he copied and missions that must be fulfilled.

Their teacher would help, but his good intentions are ground down by his own life-and-death distractions: Minato Namikaze is becoming more god than man, and all worshippers know gods have little time for mortals. They have their own divine duties, clashing with other gods on great battlefields elevated above the normal muck and slaughter of war, and their performances become the stuff of song and story - while their petitioners choke to death on blood and dust.

If Obito could be a child, he might hate his teacher, a little.

But no Sharingan user is a child, in these times, and so he just accepts this as the life of a ninja.

If not for Rin, there would be days he wished he'd never enrolled in the academy at all.

"If not for Rin" becomes a reality very shortly.

Rin's kidnapped. Minato can't help - too busy with some other mission some other place very far away.

Isn't that too damn bad.

At this point, the nightmares don't matter. The doubts don't matter. His life doesn't matter.

He's seen too many comrades be killed like animals, and killed too many animals who were someone's comrades, to care any more. He'll save her or die trying.

Samurai say that the key attitude to hold while fighting is that you're already dead. Ninja tend to take a more pragmatic view, holding that corpses make poor soldiers, and advocating survival over valor.

Samurai seem to have the right of it.

At least, that's how he finds himself, eyes and muscles burning with exertion, knee-deep in corpses with Rin by his side. She looks at him with a face sick and terrified, and it makes him just want to go home, uncaring for village or duty, and lie down and never wake again.

Until she speaks, and he realizes that look's not directed at him.

She tells him what she is - what those monsters made her. A sick joke, a ticking bomb - a monstrosity meant to kill the village of her birth, with her powerless to stop it.

"If you've ever been my friend, Obito," she says, her voice cracking, "you'll kill me."

He refuses - tells her it can't be the only option. They have sealing experts of their own - Minato's wife is both an Uzumaki and a jinchuuriki, isn't that enough? If anyone can fix it, she will. Rin just has to hold on. He'll get her back - he'll get her to a safe location, and send an emergency request for aid. Konoha won't see her dead - they can't. Being a jinchuuriki, even a booby-trapped one, is enough for them to ensure her safety, isn't it? She'll be fine, she'll be fine -

But she's weeping, and his bloodied hands are slipping upon her arms, keeping her from going for her kunai, and even he can see her chakra fouling: some Kiri scum, somewhere, has seen that the trap has failed, and is detonating it early. Through the Sharingan's second-sight, Obito can even glimpse the shape of the beast waking within her.

That is one goddamned ugly turtle.

As their heartbeats beat down to annihilation, he grits his teeth and looks her full in the face. If it ends here - he wants his last sight to be her face. "I am your friend, Rin," he says, his voice cracking, and focuses all his chakra upon his eyes.

They say Madara Uchiha could control the Tailed Beasts.

He's not Madara. He's not even a first-rate Uchiha. Still - it's not like Madara had anyone to teach him, so it must be possible -

For a moment, he sees the horrible, sickly, gluttonous thing in its cage, and, for one bright, clear, infinite instant, he holds its power in his hands, and he can subdue it, he will, he has to -

His world flashes white, then black, and opens upon an endless vista of pain.

He falls forever.

After an eternity of incoherent, all-devouring agony, he awakens to a world of darkness.

Shifting, shapeless shadows tell him the war has ended. Minato is Hokage. He is - in a way - a hero.

He cannot tell, at first, whether they are real or illusion. He would have been able to tell in an instant, once - but that is gone from him, now.

One eye can make out meaningless, blurred shapes, with the slightest tinge of color - they tell him he is lucky to have that. The other can make out nothing - it is gone. They tell him it burst within its socket, and was still running down his cheek when he was retrieved, limp and still as the dead.

He refuses to believe it - refuses to believe anything they say, stripped of his ability to know whether this is a postwar Konoha or an interrogation room in some foreign village in which the war is very much alive - until someone comes running in, and wraps him in her soft-skinned arms and cries and sobs into his shoulder how happy she is that he's alive.

And he cannot even trust her because the voice is familiar.

He can trust her only because, after all these months dead to the world, he can still feel the beast within her.

A few months later, they see fit to release him. Or, more accurately, they have decided they can do nothing more for him.

His eyes, the pride of every Uchiha, are gone. If he attempts to use the remaining one, it will be almost certain to provoke a fatal seizure. Even awakening him took an experimental medication regimen to which he will have to hold fast for the rest of his life: to forsake it would lead to unconsciousness within hours at best, and at worst seizures, world-shattering migraines, and death. Even through the painkillers, he can feel a dull phantom pain where his eye should be, the demented signaling of what remains of his left optic nerve. They tell him it will be with him forever. He should be thankful it isn't worse.

He has burnt out his chakra network hopelessly; even the weakest jutsu brings sickening burning and leaves uncontrollable muscle spasms in its wake. They told him that it was almost as though he had opened the Gates, though in an untrained, uncontrolled way; for an instant, he must have achieved unfathomable power, but at a terrible price. He would have believed their supposed sympathy more had they not carefully, ever-so-subtly begun pressing him for how he might have done it - and with such probing questions that, to a former copy ninja, it was obvious that they were seeking how it might be replicated. Sickened, he turned his face to the wall, lying and saying he hadn't the slightest idea.

Sharingan responds to the emotional requirements of the user.

He heard that years ago, an ancient Uchiha saying that had fallen into disuse and incomprehension; in his youth, something an eternity ago, he took it to be a promise of Uchiha success and trained ever harder, thinking that, whenever he awakened his Sharingan, it would surely lead him down the path to becoming Hokage. He was such a child then - a little under a year ago.

Now his Sharingan is gone, and his career as a shinobi with it.

Even if he tried to resume his duties, blinded and chakra-burned as he is, his medications inhibit his reflexes to the point he stands not a chance in combat against shinobi; even a street-fight with a civilian would run the risk of failure. Though he still lives, to the world of ninja, he is dead. Worse than dead - he took resources that might have been devoted to those who still had a possibility of redeployment.

The longer he listened to those who tended to him, and perceived the words they left unspoken, the more his suspicion grew that they would have gladly left him to die, if not for Rin.

Not for her desperate pleading, nor for any obligation to a fellow medic-nin: but rather, because they feared what might occur if they allowed him to die. The inhibition he placed upon the Three-Tails still holds, and there is insufficient data, even among the Uchiha, to determine whether that would outlive him. So long as he lives, the Leaf has a second jinchuuriki. Else -

And so they shut him away in a spare, cramped apartment, a corpse they cannot bury, and give him a small stipend as their tribute to the dead. He is not exceptional, in that regard: the war chewed up many, spat them out, and, after a brief celebration of its glorious heroes, left them in the dust to rot. He is but one of many: a crippled, hobbled, half-blind old man at the august age of thirteen.

He has some happiness that others of his sort lack: he still has someone to visit him. Rin comes to him whenever she can make time, and together they sit and talk about life before the war. It was a nice time, then: full of sunshine and smiles and dreams, rich with petty rivalries and silly hopes, with no higher concerns than training and tests and competition.

By mutual unspoken consent, the name of the teammate they lost never passes their lips.

Their teacher's name arises less and less frequently; though the Hokage visited often at first, spouting platitudes and the placid wisdom of a man with a whole body and both eyes, his presence dropped off with time, the demands of his duties growing more and more. It's not important, anyway.

If he wasn't there when that one, the one whose name they will not utter, died - if he wasn't there when Rin was taken, and changed for life - what does it matter whether he's here now?

Time passes. Rin still comes, rain or shine; even when she's so tired she passes out on his couch (the one she helped him pick out, on a day when he could summon up the will to go outside), if she can make the time at all, she comes. He looks at her, a long, blurry shape of brown and pink against the off-white blob that is the couch, and drags up, from some depth within himself that his injuries have not touched, the will to at least try to live.

It's the hardest thing he's ever done, perhaps even harder than that one surpassing instant when he achieved something far beyond his training and limits, and destroyed himself in the process; that was a lifetime's effort packed into one moment, and this is a terrible, dragging drudgery, an aching struggle that sees him silently shuffling through a village revolving around the life he can no longer live, past idiot children's gawking, and beyond his own overwhelming urge to shut his remaining eye upon a gray and formless world, lay his aching body down to rest, and sleep until the end of the world. One day he could manage with ease; a week he could endure with only a little resentment. But weeks become months, and as months turn into years, his sanity would snap if not for her.

(He sometimes wonders if it's the same for her; she never seems to have any other friends, and the only names she mentions are those of her colleagues and patients. There is still a bounce in her step and a smile in her voice, but something has changed from his memories; he cannot tell whether her sweetness and optimism truly survived the war, or whether there is only an ossified bedside manner, with nothing left beneath.)

Life becomes bearable again. He learns to find some scraps of happiness in the warmth of the sun on his face, the sounds of music, and the wind on his skin. Not enough to sustain him on their own, but enough that he can imitate a human existence, and make an effort for Rin.

They wed at fifteen, exchanging vows beneath a cherry tree shedding its blossoms.

The wedding is virtually unattended; some low-ranking Uchiha shows up at the beginning for the sake of clan solidarity, but swiftly finds an excuse to be elsewhere. The Hokage and his wife swore they would attend, but urgent business came up at the last moment - as ever. Obito's grandmother passed of old age at the start of the war, and Rin's parents on the battlefield; no one who might support them, despite all they have changed, remains.

Really, the only attendee is the ANBU tasked to keep an eye on Rin.

It doesn't matter. The world wasn't there for them when they desperately needed it, and they don't need the world now.

They have each other. The war is over. Despite everything, they're alive.

The terrified children who escaped that cave-in could ask for nothing else.

Author's Note: Originally, I had Obito and Rin marrying at seventeen. Unfortunately, then I looked up the canon timeline. That was a mistake. Nonetheless, I figured I would get fewer complaints if I followed canon and apologized for it later than if I shifted the timeline to better suit my ideas of progression.

I'll probably get complaints about making it so depressing, but the entire idea for this oneshot came from Obito using his Sharingan to subdue Rin's Tailed Beast. Unfortunately, short of time travel, there's no way to plausibly get Obito up to that level by the time of that event. Thus it had to be sheer shonen bullshit, and that must be paid off with a cost equal to the implausibility.