Mortality is something we all share, so it’s not surprising deaths show up in our stories. Whether it’s a soldier throwing himself on a grenade to save his comrades (Act of Valor) or the killer dying in flames (White Heat), you have the attention of readers and audience members when a character dies.
But remember, “with great power comes great responsibility,” as Uncle Ben tells Peter Parker (Spider-Man), not long before he dies. Before you kill off a character, ask this question: Does the death serve a purpose in the story?
Spectacle. In war stories, the mass deaths in battle may be part of the show. Often you don’t even know who just got run through with a sword. The same thing is true for a lot of monster movies. For horror stories, death often follow a plan that combines escalating gruesome wit (how the characters suffer and die makes a difference). In addition, the order of death is predetermined by impact on the audience and shrinking odds of survivors.
Commentary. In Catch-22, the soldier in white dies without meaning or mourning. It sets up the bleak world of this comedy.
Survival. Especially when Nature is involved deaths of some characters may change the chances for other characters. Cannibalism could become a factor. Or the ability to man a rowboat’s oars. Titanic became a zero-sum game as lifeboats filled up or sank.
Story set up. This is almost every murder mystery. Sadly, we won’t get to know Sir Reginald very well, but his homicide will lead to a splendid evening of suspicion, culprits, and clues.
Characterization. When and how and why a character kills another (including accidentally) leads to revealing moments that help us to know Darth Vader isn’t someone you want on your bowling team.
Character motivation. You killed my father and I want revenge. (My name is Inigo Montoya.) Or I need to get out of here before you kill me.
Loss of protection. Sometimes a character needs to die so another character won’t lean on him or her. If Gandalf hadn’t been lost, the rest of the Fellowship would have depended on him too much.
Demonstration of stakes. In Die Hard, when Mr. Takagi does not supply the combination for the vault, we know Hans Gruber is willing to kill to succeed.
Justice. This is classic, with bad guys getting theirs at the end. It could be Montoya stabbing the six-fingered man or the Death Star blowing up or Warden Norton killing himself in The Shawshank Redemption.
Values. When characters sacrifice themselves, you know what they stand for. Spartacus died for freedom, as did William Wallace (Braveheart).
This is not an exhaustive list, but it may help you to see WHY you are killing off a character (and YOU are doing it, even if you subcontract the work to a villain). If you know why, there is a better chance the death will be clear and meaningful to the readers and audience members.
Understanding why the character must die can help you in a number of ways:
Clarity - How and why the character dies need to be established right away in many cases. For a mystery or a thriller, the questions must be raised and carefully answered at the best times for dramatic effect.
Tone - If this story has life and death stakes, it better feel like that throughout, with plenty of indication early on that characters could die.
Preparation - Guns can’t appear out of nowhere. If the character will die of disease, he/she better cough early on. And preparation should include pacing so the most is gotten out of the death. This may require comic relief (since we guard ourselves against strong emotions). In a mystery, there may need to be clues planted.
There are also key decisions to make in terms of who witnesses the death. This includes decisions to have deaths off stage (or off camera).
I’m a big believer in pushing to extremes in drafts. Making deaths as painful and disastrous as possible. You can always pull back, and I’ve had to do that with some of the deaths in my stories that were too real, too gross, or too sudden. Also, never ever kill a dog. You will not be forgiven.