There's a break in the darkness from the window above the staircase, and Castiel steps right into it and while most of him is hidden under the obviously expensive cloak, there's enough of his face exposed that has Dean's sharp gaze softening somewhat. It's been...decades since he's seen anyone other than the rare hunter. And he's never seen anything this pretty. It makes his stomach twist in the only kind of fear he can really feel anymore. It makes him hesitate to return that greeting, but before he can there's the echo from his prisoner.

"Help!" It's loud to Dean's ears, and he's long forgotten how well humans hear. Maybe it can't be distinguished at all. Or maybe it can. Either way, it gives him a legitimate reason to hesitate in revealing himself and he watches for a reaction instead, curious to see what this pretty creature is doing in his castle.