How did Darth Vader die? Seriously, how? Who killed him? The script killed him. The fact is that Luke couldnt really drag Vader down to the planet and try to explain all that to the rebels. Seriously, imagine everyones reaction to seeing Darth Vader walking around, and Luke yelling about things like redemption and nice now! War crimes tribunals would not have been the right note to end on, am I right? So Vader has to die. Luke could have killed him, in a fit of anger. Or the Emperor could have killed him, jamming a knife or something in just before he dies. Or he could prosaically kill himself. Nope, none of the above. Hes just dying now. Some last words and shit, and hes dead.