Mary Winchester: Did you kill him?

Arthur Ketch: Mick was weak. He wasn't one of us. When will you realize that we will do whatever it takes to rid this world of the things that go bump in the night? Something that people like Mick and your sons are incapable of. I've been cleaning up after them for months. I took care of those federal agents they stupidly allowed to live. I killed a psychic girl they thought was... human. Honestly, they're damn sloppy.

Mary Winchester: I think you mean... decent.

Arthur Ketch: It's the end for the American Hunters. Their time has passed.