It’s a well-known fact (around this household, anyhow) that certain plot lines are going to require a sacrificial victim in order to play out in satisfactory fashion. The question that then arises is, of course, “Which character is the one who’s going to perish for the greater thematic good?” Or, as we like to put it, “Who’s got the vulture sitting on his — or her — shoulder?”
Some vulture-bearing characters are so easily recognized as to be clichés. If the book is a heartwarming memoir about a boy and his dog, for example, the dog is going to die at the end. (Unless the author is Harlan Ellison, in which case all bets are off.) This is because boy-and-dog memoirs are all about growing up and learning important life lessons, such as that all dogs will eventually die.†
Then you get the tired old cop/secret agent/career criminal who’s just one shift/mission/heist away from retirement. Don’t sell that guy life insurance, especially if he’s got a hotshot rookie partner. On the other hand, if the new partner is young and idealistic and has a brand new wife and/or kid, there’s a good chance the vulture may shift over to him instead — especially if he brings out the family pictures.
Two guys in love with the same girl? One of them has a date with a vulture instead. If the plot machine gets really warmed up, the two guys may end up on a double-date with a pair of matching vultures — which is hard on the girl back home, but this kind of plot doesn’t usually pay much attention to which, if either, of the guys she might actually prefer. (And it definitely doesn’t allow for a no-vultures-needed three-way.)
In general, if you’re a main character and you’re a guy, your plot-related vultures tend to be about dying for a noble cause, or for a girl, or at least in the line of duty. But if you’re a female main character, and have been assigned a vulture by the plot, your options aren’t nearly as attractive. You get to be betrayed and abandoned by the man all your friends tried to warn you about; or you get to expire gracefully of one of those Victorian ailments that killed off characters like Mimi in La Boheme and Beth March in Little Women; or you get to walk down the wrong street on a dark night to the accompaniment of ominous music on the sound track, and meet an unpleasant and bloodstained end.
A well-done vulture, on the other hand, is one that’s so skillfully foreshadowed that the reader doesn’t notice its presence until the character’s fate has played itself out, at which point everybody realizes that the vulture was there all along.
†For some reason, memoirs about girls and their dogs are considerably thinner on the ground, possibly because teaching important life lessons is supposed to be a manly — or at any rate proto-manly — thing.