there’s a very real possibility he’s going to kill your character. The most
efficient way, given the circumstances you’re providing, for him to make
absolutely sure they’re not going anywhere would be to snuff them. It’s also
safer. If they’ve just been engaged in a duel, using weapons that are designed
to kill people, then it’s going to be a lot easier and safer, to simply finish
the job, rather than to drop his guard, hope his opponent doesn’t use this
opportunity to pull a hidden weapon, or try something futile and reckless, like
dragging them both off a balcony. If your character does not care, then the
smart thing, the safe thing, given the circumstances, is just to finish the job.
It’s not to stop, give their foe one last chance to mess things up, while they
step back from this for a second. Your characters operate under the
restrictions you set for them. You define their personalities, what lines they
will and won’t cross, and in general, who they are. That informs how they
should respond to situations they encounter. With rare exceptions, they do not serve the plot in defiance of
who they are. They should always be following their own identity and agenda. When
that conflicts with the plot, you need to decide: Either move them elsewhere
(rewriting scenes as necessary), completely change who they are (rewriting
everything involving that character), or they win.
a character who wants to stop someone from going anywhere. They don’t care if
their foe lives or dies. Death will make sure their foe doesn’t wander off, and
it’s far more reliable than breaking a leg or severing the Achilles tendon. In
those cases the defeated character could, potentially, drag themselves to help,
and screw things up.
Unless your character has an actual, internal, reason to avoid killing
their foe, you’ve just killed one of your characters. You made the choices that
lead to this awhile back. This is the secondary or tertiary consequences of
your character building, and the way you’ve positioned your characters. However,
it’s a legitimate kill. It will affect your plot going forward.
times, saying, “this will mess up the plot,” isn’t really a reason not to do
something when you’re originally drafting a piece. Later, in rewrites, where
you’re multiplying work for yourself, then it’s a legitimate concern. But, when
you’re writing a scene, and realize that one of your characters would flat out
kill the person they’re fighting, saying, “no, I wanted that guy for later,”
isn’t a good reason to walk back the kill at the final moment.
on how creative you want to be, and how willing you are to mess with
expectations, it’s entirely acceptable to kill off major characters this way. That
said, you’re going to need to address the character’s death. If your story
really isn’t set up to do that, then it’s entirely possible your killer doesn’t
fit the tone of your work.
also entirely acceptable to have a character that doesn’t want to kill people. If
that’s the case, then you’re still looking at rewriting earlier material to
suggest that’s the case (even if you don’t spell it out.) This is a legitimate
character outlook. They’ll go to violence, but draw the line at executing their
opponents. The problem with this is, depending on your setting, they’re probably
dealing with foes who lack that qualm.
situation where one of your characters needs to remove another from the story
is a problem. When that character is willing to kill their obstacle, the
problem is self-solving. As a writer, when you get to a moment like that and
go, “this is a problem for me,” it’s usually a sign you need to reevaluate the
situation you put your characters in, or where your story is headed.