Disclaimer/author's notes: Naruto is owned by Masashi Kishimoto, not me, no profit involved. No warnings.
Sasuke sits, cold and disinterested as if he feels nothing inside (as usual—as an Avenger, he has to kill his insides) watching the people around him live.
Kakashi is shrugging-stringing together some bullshit about an old lady and crossing the road. Sakura has a hand on her hip, green eyes flashing like grass about to poke through dirt with her protestations. Naruto is yelling, shouting, reminding the entire world he is breathing as usual. They look so alive. Sasuke lets his eyes flicker to the ground before snorting and grinding his heel into a mountain of ants.
The ant-mound collapses, ants scattering as their world collapses around them (Sasuke knows the feeling). Naruto notices this and snarls. What the hell has happened to make you like this, he demands.
Life, I've lived, Sasuke responds before wandering off in his mind. The world that does live does not follow him. Sasuke knows he does not want to be like this—cold and cut-off (lonely, Gaara's dead voice echoes like scattering bats inside his head)—but he is not sure there is anything else he can feel. He must feel like this if he is to be an Avenger (capitalized in his mind's eye to give the word a purpose) and kill the Murderer (capitalized in his mind's eye to give a reason for act causing this name—not the word itself, the word is clear enough, murderer means one who has murdered—other than why?).
But before Itachi was the Murderer, Itachi was Brother. Before Sasuke was an Avenger, he was a Brother too. This was their old world, but Itachi killed that in most all the ways that mattered. Sasuke is not sure if he likes what is left behind (himself, an Avenger).
Once the reason for why Sasuke is Avenger bleeds out, Sasuke will not only be no-longer Brother but also a Brother-Murderer (he always wanted to be like Itachi; the desire mocks him).
What is left of Sasuke's world will finally be killed, dead in all the ways that matter, and Sasuke will be left to create a new one ( he says he wants to restore his clan; the words mock him).
Sasuke's eyes focus on the ants scattered at his feet, swarming and stumbling to rebuild their smashed home. Sasuke snorts once again.
Sasuke watches Kakashi slouch carelessly as he watches Naruto and Sakura. Sakura's agile fingers play with her hair as she watches Sasuke and Naruto's hands wave as he watches Sakura. Sasuke hopes they keep their lives ones they want living.