Multiple deaths can add unpredictability, all though don't over do it. Also, a secondary character death can add just as much emotion without completely uprooting the plot-it could create grief and stress for the hero or major characters.
[header] How to kill off a hero or other character [title] Decide who you want to kill off. [step] It sounds simple, but there can be multiple heroes. Maybe you want to kill off the secondary character, or kill the villain but then have the hero die unexpectedly.