...and I don't understand the question. The characters in my stories die when they're supposed to, and not a moment earlier, or a moment later. I don't have to "arrange" their death, they know themselves when its time for them to die and they die. Here's an example; I wrote a science fiction story that took seven books to tell. During that time, new characters were introduced and became part of the story. I've noticed this trend in any story that lasts a long time, most notably on TV series on Netflix, Hulu, Amazon Prime or some other streaming service. With the constant introduction of new characters, a process a writer has little control over, there is a need to have characters exit the story so as to not "clog things up" with too many characters. This can be accomplished by killing the character, or "putting him on the bus", i.e. sending him away from the place where the story is occurring. This type of death may or may not be dramatic. Usually, a good time to kill a character is after he's completed his story arc and is no longer needed to advance the story you are telling. Another good time to kill a character is when it's most dramatic for him to die from the point of view of other characters. When writers start threads saying they're "agonized" by the decision to kill a character, I fail to understand the problem. Killing a character happens when it serves the story, and never at any another time.
Okay enough - we've already had one thread on how your characters are autonomous complete with the attendant argument..we don't need another