Sasuke knows that Itachi isn't his. He knows that he never will be.
If anything, Sasuke belongs to Itachi, and even still he's simply a pet and a plaything. Itachi would never let it be anything more, and he knows this all too well.
Sasuke knows that Itachi isn't his, and yet he's well aware of the possessive jealousy that rises every time his brother so much as looks at someone else with anything more than his usual impassive gaze.
He knows, and yet he still finds himself making threats. "You're busy," he says to the girl, eyes blood red and dangerous. "If he asks for you, you can't see him," he says, kunai to her throat. "If I find you so much as touched him, I'll kill you," and he means every word. He's done it a dozen times by now, and if Itachi's noticed, then he's letting it continue.
Sooner or later, his brother is going to stop him. He's going to punish him and twisted as Sasuke is he's going to enjoy the attention. He can only hope that Itachi enjoys the screams as much as he enjoys screaming. He can only hope that he'll be allowed to stay because as wrong as it is he can't stop.
When his alternate forms of entertainment fail him, Itachi is frustrated, but Sasuke only lets it bother him a little that he wasn't first pick. He doesn't let it bother him too much because Itachi is rougher when he's frustrated, and Sasuke likes it when he's rough, likes to bleed for him. He feeds off the pain his brother gives him like a drug, and sometimes it's hard to remember why he ever hated him, that things weren't always like this.
At one time, his greatest fear was dying before he killed the man who killed his family, his clan. Now, the only thing he fears is that man leaving him, throwing him out like an outdated toy that's lost its shine and doesn't quite work right anymore. Sasuke never wants to be obsolete in Itachi's eyes. He never wants Itachi's interest in him to fade.
Somehow, he thinks he might be in love. It would be stupid to mention it to Itachi, and so he doesn't, but he wonders how long he can hold out if it's true. One of these days, he might just let it slip. He wonders what will happen if he does, and the fear of being left alone keeps him quiet.
Sasuke knows that Itachi isn't his, but he can't help but want him to be. How wrong it is doesn't even cross his mind anymore, only the desperation caused by knowing how quickly it could all end. For now, he's content with living in his fantasy, so long as Itachi stays by his side.
He knows Itachi isn't his, but he can always pretend his name from those lips actually means something. He can pretend that these acts are done out of some sort of love rather than for pure entertainment. So long as the word love doesn't pass between them, it can't be rejected, and Sasuke can keep on pretending.
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