No Longer Needed By The Plot
Characters die, not because of cause-and-effect or morality of the story, but that the plot no longer requires them.
Similar to You Have Outlived Your Usefulness, except instead of being killed because they no longer needed to serve the plans of the Big Bad, characters die because they no longer serve the plans of the author.
Hello, Unknown Troper. You'll need to get known to lend a hand here.