I feel like the movie Mortal Kombat, while flawed, does know the best ways of killing off people. It's good to learn from, as nobody dies randomly or for worthless reasons. Like how when Sub-Zero kills off the poor redshirt with his ice powers, this is a demonstration that Shang Tsung (who has SZ brainwashed) will do anything, cheap or not, to win. The redshirt's death is thus meaningful, and the audience feels bad for both him and the next person to fight Sub-Zero. So yeah, my suggestion is to watch Mortal Kombat (or some other movie if you want) and figure out why it was important for those characters to die.
I killed one of my characters recently. But she deserved it. I don't mean that in a bad way; it was just that she had turned into a sort of goddess-incarnate and she had to die as a heroine. Or a villain, from another point of view. Suddenly that sounds very shallow of me...
Finally, a writer that DOESN'T let an "overpowered" character survive! I swear, I hate reading books about these all-mighty heroes of time, whose abilities surpass those of everyone around them. Heck, I'd try and get those characters killed off the quickest! To add to this, if I hate a character as a writer, and I want him/her dead, then I'm sure there would be others in the book that would want that character gone even more. In my defense, I'm not the one driving a bullet through their skull. I let my characters do what they need to, and leave it at that.
I generally kill characters, or rather, let them die, whenever it seems reasonable and/or is likely to improve the story. For example, I tend to dislike reading stories where the main character or any other character seems to avoid death in miraculous ways over and over, it just makes me loose interest as I know the character won't die anyway. Of course it depends on the story, you wouldn't expect the same from a fairly tale as a more realistic story.
Your job is to present the story. Emotional investment in your characters is inevidable, but to kill them for the power? ... Narcissism is one of many emotions a writer needs to represent, not display in spades. A writer litereally speaks for the characters. You can't speak for people if you don't understand them. My point (if there is one) is that wanting to kill your characters for the power is the act of an emotionally immature person. A writer needs to understand people in order to properly wirte them. The writers you're talking about are probably going to have thier dialogue give them away. Writers who don't see people (REALLY ovserve them), or understand a small spectrum of our emotions have every character sound the same. The have the same inflexions in thier speech, the same structure, the same attitude. in short: A writer worth reading will be more mature than that.
