They have learned to suppress their divine Breath. This allows them to hide, but they must be careful never to give away all of their Breath. Denth has been a Drab before—he’s not completely lying—but never for longer than a few days. And his divine Breath is always there, suppressed. So he doesn’t know what it’s like to be a true Drab, which is why in this chapter he says he doesn’t think it changes you that much. He’s never felt it.