It really was like night and day. The casual tone made the trace of sadness catch Aziraphale's attention even more. Castiel - or a version of Castiel, in any case - had only made the briefest of impressions upon Aziraphale before he was sent to Earth, but the loss of anyone was painful. With a twist of his mouth, he bowed his head briefly and mouthed "Sorry," for lack of anything better to say.

He did wince a bit at "demon-smiting". One of the downfalls of associating with angels, he supposed.