"No!" Aziraphale is practically vibrating with impotent indignation now. "I am not fallen at all! I'm a proper angel, a principality is a kind of angel, just - where are you getting this?! Crowley's the one who's fallen. And he's not evil, he's-"

Oh dear. Crowley would hate him saying that. Aziraphale's not sure how he feels about it either.

Aziraphale pinches back his annoyed babbling with pursed lips and a moment of silent consternation. "He's complicated," seems like the best way to split the difference.