Annie. Dean misses her, just as he's missed all of them, but the ache is mixed with guilt, a need to make things right with her kindling, faint but there.

"Miss her," he says, and would laugh if he could, standing in the middle of all this ruin and missing his fucking dog. He lets Castiel take his weight, keep his head upright so Dean can open his eyes and look at him. "Don't you fucking dare. If I go anywhere, you stay. You look after all of them."