Amoracchius could kill a demon

I blinked. "Bob. Is it possible for something like a demon to leave a ghost?"
"Oh, uh," Bob said, "I don't think so - unless it had actually died there. Eternally perished, I mean, not just had its vessel dispersed."
"Michael killed it with Amoracchius," I said.
Bob's skull shuddered. "Ow," he said. "Amoracchius. I'm not sure, then. I don't know. That sword might be able to kill a demon, even through a physical shell. That whole faith-magic thing is awfully strong."
"Okay, so. We could be dealing with the ghost of a demon, here," I said. "A demon that died while it was all fired up for a fight. Maybe that's what makes it so ... so vicious."


Grave Peril Chapter 18, Page 170