I've been perusing the last several posts, and the takes on the various views about that last scene on Mustafar as well as Ben's motives are interesting. Much of it I can agree with. One thing, (especially concerning those so ready to "condemn" Obi-Wan on that other mercy killing thread,) is that it is so easy to look from the outside and judge the thoughts and motives of a person on the inside of a situation, Whether what they did was morally right, wrong, justified, etc. We see it all the time in news events. It's easy to say what the right thing is to do when one is not in the middle of that circumstance. But no one really knows how they will respond in a real circumstance until they are in it. I don't see Ben as vengeful at all, though. Now, the rather "unfortunate" thing is we have "A New Hope" before we have "The Return of the Sith", but to me, Ben, although you could see regret and sadness in it, saw the duty that needed to be done. His former apprentice was a monster, coldly murdering anyone who stood in his way, putting fear in the hearts of millions, etc. Maybe Obi-Wan had nearly 20 years to "beat himself up" for his weakness and attachment that prevented him from finishing the job on Mustafar, maybe every time he heard news about a new atrocity performed by Vader it was a slap in his face and a reminder to him about the fact he couldn't outright kill his best friend and brother. But I don't see his motivations to Luke as vengeance, but more like "It needs to be done." In a way, "Finish what I couldn't do." I can see Obi-Wan heartbroken words at the end of Mustafar perhaps being a plea for Anakin to turn back to the light...(and the heartbreak in that scene was so palpable), but perhaps over the years he saw Anakin/Vader not only NOT turn back to the light, but instead grow more powerful and evil in the dark so by the time Luke came into the picture, Obi-Wan had pretty much become convinced the only hope for the galaxy was the death of Vader and the Emperor. He likely ceased to even think of Vader as Anakin after a while, that's why he could say that "Darth killed your father," ..because to him, he did. Thats my two cents...if it's worth anything. Obi-Wan is still the hero of SW's to me.