There's one thing that preoccupies Uchiha Sasuke as he turns from a student of the academy to a Genin and as he carries on from there, and that is the passage of time. Each minute, each day, each slow month from the day his clan died is another month, minute, day that their murderer has outlived them.
But Sasuke doesn't see time that way, mostly. He thinks that when he's morose and extravagant, when he lets sorrow-born ambition occupy his lonely mind. That's not often, or at least not always. For most of the days, he sees the passing time as a bit more of his childhood, a little longer he has to spend helpless. Just another interminable period of his ineffectual youth, just more ineffectual training, just a while longer in immaturity. More time spent in a little boy's body, giving cold looks to people who try to rehabilitate him, who want to help him get over his understandable grief.
They don't understand. Mental trauma, psychological damage. Those terms are for victims, and he, the last Uchiha, can not be a victim.
His brother killed his mother, killed his father. They, the ones he killed, those people are victims; he, Uchiha Sasuke, is not. He is their avenger.
So each moment of Sasuke's life doesn't tick forward from his birth, or even from the massacre (The Uchiha Massacre – so very notorious, so much more important than the day he was born, it was the day he was reborn, brought into his role as a 'tragic hero'). No, Sasuke's way of measuring his own life is counting down, waiting until the day his reason for existence is fulfilled. Until he has killed his brother, he will live to kill him.
He imagines sometimes, in a grandiose fantasy, that his life will be split into three neat sections. Infancy, seen idolising Itachi. Seen dependent on him and even then living for his sake. Childhood - no, Adolescence - will be a period of rebellion against the ideal that had defined him until then. It will be the part of his life he spent trying to destroy Itachi, the time he was An Avenger, living for no other reason. Vengeance, his reason to exist.
He stumbles when he comes to the next part – Old Age? Renaissance would be prettier. Rebirth, it means. He hopes, vaguely, that he might have a chance to rebuild the clan; married, with kids. Adulthood might be a better word, then.
But it makes him uncomfortable to think of a life without the purpose that governs it.
That's why he wasn't sure when Kakashi asked him for his dreams for the future. It's an goal, not a dream. Better still, an aim. A neat target through the Uchiha fan on the back of Itachi's shirt. Insert kunai here; your job is done. Not a dream, not a fantasy. There's no pleasure in the deed except the joy of liberation.
His brother told him to hate him, but it's not quite that easy. Sasuke remembers, you see. Before the massacre, before the slaughter, what the Uchiha clan was like. No-one else does, not so inimately. But it's not easy to look back, he doubts the memories and mixes them with pastel-coloured rose-tinted lies as he tries to revere the dead (as is proper). But it comes down to this: he liked Itachi. He genuinely liked his brother, and he didn't like any of his peers, or many of his relatives. He spent days following Itachi in adoration – it's humiliating and painful to remember, which is where the hate of his brother was spawned. But those memories also fill him with melancholy, because he's quite sure he'll never love or admire anyone so unconditionally again.
He makes himself hate the memory-Itachi, he makes himself love the memory-clan. It's his reason to live.
He backed away from society after the massacre, which wasn't hard because his entire society had been the Uchiha society, he'd been on speaking terms with less than five outersiders, seen from behind his mother's knee or the heights of his brother's shoulders. Everyone who'd offered him condolences had been abashed and easily driven away. He'd isolated himself easily for the first few years, resolve and pain outbalancing the loneliness – loneliness was easy to convert to another emotion, grief or hatred or determination. He trained, and became cold.
His reason to live was to kill, he didn't want friends to soften him again. Mangekyou mind-images burnt over books and happy stories, class-rooms respected his silence so he didn't offer them sound. His life was routine, tedious as he waited to grow up.
No-one got past his identity as orphan, few even glimpsed his role as prospective avenger.
Not until genin teams and Uzumaki Naruto. Girls tried, constantly, but they were irrelevant to his purpose and easy to scorn. Fools, petty giggling idiots, bland, superficial, blind, silly. Overall: silly, that was how to describe them. Doting, weak, pathetic, adoring.
If they reminded him of how he'd followed his brother, and sometimes a stray word or glance would make that connection, he'd turn and snap at them in his frostiest voice. And they'd run away crying, and he'd hate them all the more.
But... Uzumaki. He was bumbling, blond, cheerful, blind, and in every way a fool, inferior to Sasuke. Sasuke made up his mind to ignore the blond, knowing it would be easy because of the klutz's dislike of him. He wasn't bland, but he could be tuned out. And dislike was better than admiration, which was what the pink-aired Sakura held for him. They would both slow him down, he thought, trying his best not to listen to either.
But they didn't just slow him down, they interfered. Uzumaki was distracting – his strength came out in full force just to anger Sasuke – dumb perseverance. It drew the Uchiha survivor into competitions and arguments and rivalry. Dislike was replaced by that, by rivalry. By interaction with the real world, or at least with one real person.
Just what he'd been trying to avoid.
Naruto was an opposite to Sasuke, in so many ways. It took the genius a while to figure them out, because it was strange. Naruto was an outcast, socially rejected, and yet still struggling like a ... like a dumb, moronic, thick-headed Naruto-like thing to cling to friendship and happiness. Idiot's ideals that Sasuke had rejected, and fiercely told himself not to miss. He didn't miss them, he had training to do. Naruto was useful for training, and that was it.
It took him longer to realise that through the denial he admired Naruto, in the way you do a distant saint or martyr. It was illogical how bright and determined the blond was. He stuck to his goals much like Sasuke did, but... he admired society. He was a patriot, an exiled patriot. Why did he love his land? Why was the friendship of weak, girlish, doting Sakura so meaningful to him? He was strong, because he trained and trained. And at the same time he found it more important to joke and make Kiba or Shikamaru laugh than to listen or learn. Sasuke had seen people like that, sucking up to those seen as cool, but Naruto wasn't one of them. He didn't just want popularity, and yet he didn't just want strength. An enigma, indeed.
But Sasuke found himself drawn to this enigma. The loud prankster was likeable, and he wanted to like him.
It was completely logical that he left. Naruto fought the Curse Seal, the urge to complete his mission fighting his (weak, pathetic, useless) need to make a friend. Running up trees with Naruto had shown him he was lonely, they'd been tentatively reaching out and getting to rely on each other more and more. They were becoming rivals, growing to be each other's purpose and challenge. But - Naruto was a distraction, thick, dumb-ass, retard, dead-last. He couldn't let himself be held back, he told himself, reciting lists of epithets for the cheerful blond and trying to make them spiteful.
It was a war between power and spirit, and his logical mind told him to seize the day.
Naruto had been getting stronger day on day, and the Chidori had been inadequate against Gaara.
Naruto was strong, and Sasuke couldn't forget how he'd seen the Rasengan carve out an expanding tract through the water tower. He couldn't forget that, he had to give up the rivalry, unless he wanted to lose the dead-last (to become the dead-last? He couldn't be Naruto, he could never, ever fight for approval. He hated that about Naruto, he would make his own way). He wasn't strong enough and didn't care enough to be Naruto, he was a genius and didn't need to. He wasn't going to lose to Naruto, though.
He would lose the dead-last.
He wouldn't lose to the dead-last.
He would leave the dead-last (he wouldn't lose him) - he would complete his mission.
Maybe when he completed his vengeance.
Maybe he could dare to hope for friendship then. He couldn't allow himself it now.