They had always understood each other, even when they were younger. Of course, their understanding wasn't as complete as it is now, but then, it hadn't had to be. Even if life wasn't simple then, it was at least less complicated. And so because they had understood, they fought constantly, words and fists flying until they were too exhausted to move, until they were too exhausted to think.
That was the true reason they trained and fought with each other. Sakura didn't give them enough challenge, wasn't strong enough for them, and Kakashi would have stopped before total fatigue had set in. With each other, they never had to worry about that, because they both understood the need too fight until completely overwhelmed.
That need wasn't simple, but it wasn't too complicated either. There was the surface of it, which was the desire to become as strong as possible as quickly as possible, so one could gain respect and maybe even love and so the other could someday avenge his family. But there was also a deeper need. That is not to say the first was not important, for it was, very much so, and accounted for a good deal of training, but a need such as this is always multilayered, and it was the second layer that only the other truly understood.
The need to be so tired that they would immediately fall into a deep sleep, so tired that they would not stay awake and stare at the ceiling with the loneliness pressing in so badly that it almost suffocated them. When they slept, at least for a few hours, the oppressive silence and heavy air that came from being the only one did not weigh them down. That is, of course, when the sleep was dreamless. And sleep was only dreamless when the body could no longer sustain the mind.
As long as they trained enough, they would fall asleep quickly and they would not dream, not of blood or hate filled stares, not of mocking laughter, either of a once loved person or an angry villager, and certainly not of smiles, laughter, and family and what might have been if things had been different, if they had been different.
Those dreams had always hurt the most, dreams of what might have been if Itachi hadn't been a prodigy in whose shadow Sasuke had grown up, and if he hadn't killed the whole clan, leaving only his brother, the weakest of the Uchihas, alive. Dreams of what might have been if Naruto hadn't been an orphan and if he hadn't had the demon fox sealed within him. A dream of what might have been if they hadn't been alone with only each other's understanding for comfort.
That was not to say that no one else in the village would have understood that need, for it was a hidden village and many feared both dreams and insomnia, but the two were only children, despite the fact that they were genin, and one was hated by the whole village and the other adored by it. For the first, there was no one else who would have cared to understand, and for the second there was no one else who could see through the glamour of being the Last Uchiha to understand what it truly meant to be the last one left.
But, as mentioned before, as children, their understanding was not total. It did not, in fact, become perfect, until their fight at the Valley of the End, where for the first time they became truly and completely furious with each other. They had been angry before, but never like this. Because, as one's hand punched a whole through the others chest, it was the first time they actually hated each other. Naruto hated because he could not understand why Sasuke could not stay, why he had to run off to Orochimaru, and Sasuke hated because Naruto couldn't understand. So maybe it's better to say that they hated each others lack of understanding, instead of the person.
It was the first time they hadn't understood each other.
Even though they had gone through the similar experience of being alone, their lives had been different. Sasuke understood what it was like to want respect for one's strength because that was what he had longed for with both his father and Itachi, but he couldn't understand why this need was for the village to love and respect him, because neither of them really knew anyone there, not enough to love and respect them in turn.
But then, Sasuke had always been the village's golden boy and despite everything else he had never been hated by his family.
Naruto understood what it was like to have nothing, but that was all he'd ever had. He didn't understand this compulsive need to ruin a life just to achieve vengeance for a loss. Sasuke's family had been the police force, and they would not have wanted their son to betray all they had stood for, not even if it was for them.
But then, Naruto had never lost everything that made up his life, mostly because he'd never had anything to lose, and so had no desire for revenge.
All that changed after the fight though. Because it was after that fight that they understood why the other had done what he had done, and they could no longer hate.
After all, you can't hate something you understand.
Naruto understood how Sasuke could leave everything behind for his family, because Sasuke had become a part of Naruto's family and he was willing to do anything to get him back. And Sasuke understood Naruto's craving for love and respect because after he left, he realized that he could never go back, and if he did, the village, who had once worshipped him, would spit on him for being a traitor.
They met again three years later, over the corpse of Itachi, their understanding of each other complete. It was Naruto's hand that held the knife and was stained in blood, but it was Sasuke's need that had driven the hand, and that was enough to satisfy his revenge.
They looked at each other and neither spoke, though both knew what the other wanted to say. In the end, it was Naruto who broke the silence, and even though Sasuke had known what he would ask, he breathed an inward sigh of relief, because those two words assured him that Naruto understood and did not blame or hate him as so many others did now.
"Come home."
And Sasuke came the closest he could to a smile, as much as he was capable of now, and Naruto returned it with one of his own. Not one of those smiles that hid himself, but a smile that revealed himself. It was one very few people had seen, and Sasuke understood that, just as he understood that this would be the last time Naruto would ask this question, and just as Naruto understood, without Sasuke saying a word, what his answer would be.
That was why, a week later when the Anbu team, led by Naruto finally caught up to him, there was no surprise in Sasuke's eyes as Naruto drove the same kunai through Sasuke that he had driven through Itachi. It was Naruto's final gift, and Sasuke was grateful. That was also why, when Naruto stood under s clear blue sky next to Uchiha Sasuke's grave, he did not cry. After all, both of them knew that by then, no matter how much they wished otherwise, it had been too late, Sasuke had done too many things for redemption to be possible. And if there was an extra bright sheen to the Rokudaime's eyes, Naruto knew Sasuke would have understood why he did not and would not cry for his death.
They had always understood each other after all.
