The prompt was:
Sam: "There's some part of them that... that's keeping them here. Like their remains, or unfinished business."
Molly: "Unfinished business?"
Sam: "Yeah. It could be revenge. It could be love, or hate. Whatever it is, they just hold on too tight. Can't let go. So they're trapped. Caught in the same loops. Replaying the same tragedies over and over."
Bishop to H5. Check.
Crowley screams as he is consumed by fire, along with his bones. He knows he'll come back, he knows he will, but that doesn't make this hurt any less.
Pawn to G6.
Crowley comes back to himself on the cold hard tiles of his newly reformed Hell. He stands up, dusts off his pants, and walks down the endless hall of souls, smiling.
Queen to A5. Check.
Castiel coughs up a mouthful of blood and looks down at his hands in shock. They're glowing, leaking grace and power and he doesn't know what to do - he's lived for eons and he just doesn't know anything anymore.
Knight to B3.
Dean kneels next to where Castiel has fallen and takes his hands. "Let go, Cas. You have to let it go. It's okay."
Queen takes Knight.
The Wall collapses and Sam screams.
Dean hears him screaming, but he can't see. It's too bright- it's just too damn bright.
Castiel stops holding the light in, and lets it consume him.
Sam stops screaming.