Why on earth would Micah of all people put “vengeance is hereby mine” on his revolver. There is no revenge story in his background and he never says anything about killing someone specific with that revolver. He did carve it on his revolver so we can assume that whoever he may have killed, he killed with that weapon. But it doesn’t make sense. The only thing I can think of is when John goes to mount hagen he claims vengeance on Micah, and is rewarded with the revolver, essentially saying vengeance is hereby mine. I just don’t know though. Any ideas?