I think the event that changed Hob was when he was being forced to kill Hazel

I think the event that changed Hob was when he was being forced to kill Hazel, but resisted and fought the psychnosis that Brother Jakob had put on Hob, as it says on page 160, “‘ … Psychnosis will not change you. It merely prevents you from divulging anything about the Fellowship…'” I think that this “psychnosis” is something that forces someone to do one’s bidding. I think that on page 544, “Hob brought the sword up, but there it remained.” Shows that he fought the “psychnosis” Brother Jakob put on him. So in all, I think that Hob changed because of that event.