Humans are the Demons
“Someday we will run out of demons to fight here in Cinnabar,” Prudence told me one night after saving an old lady from a swarm of flesh-eating cockroaches.
“That is far-fetched for two reasons. For some of those creatures you kill, you humans are the demons. Absolute goodness is also never possible,” I said, doing air quotes with one of the words.
“Sooner or later we'll feel bad about only saving people's lives here. What about the neighboring cities?”
“Does that mean you don't feel bad for them now?”
“Sometimes but there's only one of me trying to save everybody.”
Prudence also appears in the novel I Killed My Friends and It Thrilled Me.