Sam feels his mouth twitch into a satisfied grin as he watches the vamp feed Dean his blood.
Sam wants to be sick; he can feel his brain thumping against his skull and he feels his hands curl into clenched fists.
What he wants to do is to run over there, behead the vamp and take his brother into his arms and hold him tightly. What he does is just stand completely still, studying his brother as if he were some sort of experiment – which in a way he is…
He knows what it is like to be possessed; he had Meg riding his body like a whore rides her favourite client and he had Lucifer inside of him for days – weeks even. He knows how much it hurts to lose control of your faculties, to have someone else make the moves for you.
Dean's eyes flutter closed and he makes his way over, swiping the knife at the vamp and getting a punch in the jaw for his trouble. When the fight is over and the vamp is gone, Sam lifts Dean up and carries him to the Impala, knowing what the result of this will be.
Days later – when Dean takes the cure – Sam sees by the look in his eyes that he remembers. Sam wants to hold him, to hug him so close that Dean will love him again, trust him. His body twitches but his brain holds it back, taking control of his actions, making sure he doesn't do anything he will regret.
He knows what it is like to be possessed; Lucifer rode him until he was eaten up and aching with it. Lucifer controlled him and taunted him and when he finally did take control of his own body it was almost too late.
He remembers Dean's blood on his hands, the sound of Bobby's neck breaking, the pop Castiel made when he exploded. He hurt his friends and the pain of watching himself do that will never, ever go away.
When he crawled from the pit he knew that he was in control of himself, he knew that Lucifer was gone and that he was no longer one part of a whole. He stands on the wet grass and stares at the stars and he vows that no one will control him like that again.
So now he controls himself. His brain sends signals to his body and his body obeys. Sometimes his heart sends signals too but his brain makes him ignore them. He was once a man of faith, of love, of hope but now he is a hunter through and through.
He knows what it is like to be possessed and as he watches himself go through the motions of life he realises he will never, ever be free…
End