In short I'd like to write a story from the point-of-view of a character who ultimately dies within the narrative without the story being either A. a ghost story or B. a life/after-life retrospective narrated after the fact by the dead character. What techniques can I use to write a first person, present tense, narrative from the point of view of a character who is clearly dead. Is there a trick to doing this without creating a moment of frisson when the narrator dies or is there always going to be a jolt there? I'm trying to gauge, among other things, whether I can kill a character and still have them give a post-mortem, for them, wrap without changing the narrative into something I don't want it to be.
Building on Galastel's third option, you can prepare for the impending death by introducing the reader to a second narrator earlier in the story. Many stories, especially those which conclude romantically with two main characters getting together, use a split narrator arrangement where alternating chapters are narrated by each of the two star-crossed characters. This allows the reader to really get to know each of these characters and thus amplifies the joyful ending since the reader can see it from both sides. Your usage would be a little less joyful, but at least you would have an established and recognizable voice available to pick up the tale after the other dies.
There should be a jolt when the main character dies, in fact when any character the readers sympathise with dies.
Now, what to do with the first-person narration and the death?
One option, is to narrate right on until the death, as usual, then cut off. Depending on the metaphysics of your story, it can be right at the moment of death, or a little after. Here's an example from Jim Butcher:
I came out of the cabin and into the early-afternoon sun, quivering with pleasant tension and tired and haunted—and hopeful. I shielded my eyes against the sun and studied the city’s skyline.
My foot slipped a little, and I nearly lost my balance, just as something smacked into the wall of the cabin behind me, a sharp popping sound, like a rock thrown against a wooden fence. I turned, and it felt slow for some reason. I looked at the Water Beetle’s cabin wall, bulkhead, whatever, behind me and thought, Who splattered red paint on my boat?
And then my left leg started to fold all by itself.
I looked down at a hole in my shirt, just to the left of my sternum.
I thought, Why did I pick the shirt with a bullet hole in it?
Then I fell off the back of the boat, and into the icy water of Lake Michigan.
It hurt, but only for a second. After that, my whole body felt deliciously warm, monstrously tired, and the sleep that had evaded me seemed, finally, to be within reach.
It got dark.
It got quiet.
I never moved, but I saw a light ahead of me. With the light, I saw that I was moving down a tunnel, directly toward it. Or maybe it was moving toward me. The light looked like something warm and wonderful and I began to move toward it.
Right up until I heard a sound.
Typical, I thought. Even when you’re dead, it doesn’t get any easier.
The light rushed closer, and I distinctly heard the horn and the engine of an oncoming train. (Jim Butcher, Changes, Chapter 49)
Another option is to narrate until right before the character goes to the battle where he's going to die / whatever else happens that is going to kill the character. In this case, the death is implied. However, this option only works if the reader (and thus the character) is aware of the high likelihood of death. Anything that needs to be settled would thus be settled before the character goes off to die.
A third option is to switch to a different narrator once the MC dies. The new narrator can then wrap things up. However, in this case you have to make it very clear that you've switched to a different character. Otherwise, it would be confusing to the reader.
All narrative construction in any work of fiction is itself a fiction. This is especially so with the point of view of a story's narrator.
For example, third person omniscient narration is narrated as if it was observed from someone or something with a god-like point of view. This could be a historian which does make sense. After all, historians can write stories. Novels and short stories, even screenplays, whereas works of history are intended to explain what and why history happened rather than telling history as stories (which is the business of fiction).
There are first person narratives apparently "written" by narrators who are functionally illiterate inworld. This is a conceit. As a reader, we have to assume this first person narration was set down as if it has written by someone who cannot actually write it down.
Therefore, a first person narration narrated by a narrator who dies somewhere in the story is both a conceit and fictional construction. The conceit being we as the readers and the author pretend that the first point narrator can continue the narration despite the death of the narrator. The fictional construction is precisely that, it is a let's pretend this is how it happens thing that we make up.
The story doesn't turn into a ghost story if the author doesn't bring ghosts into the picture, The narrator can simply die in the middle of their narration and continue on telling the tale as if they had been alive and well and able to the tale.
Don't sweat it. Just do it. If you carry it out with confidence and determination, you will bring the readers with you.
After death experience.
IRL many people with stopped hearts or that have clinically died, or been very close to death, report after-death experiences. Floating above their body, hearing (and reporting) conversations and sights it seems impossible for them to have experienced (including since their eyes were shut). Being able to rationalize and even know they were dead (or dying).
This phenomenon is the only route I see to avoiding supernaturalism; you could have a page or two after certain types of death in which the brain is intact (like being shot or stabbed in the heart, perhaps an overdose or poisoning) in which your character has extreme clarity and deductive powers: With the evidence they have been killed, perhaps by whom and how, they can deduce the wrap-up, solve any remaining mysteries (and tell us why) and what must happen next.
Of course this route will leave out actual interactions, perhaps it will be more of a summary, ending with a line like "And knowing that, I let go of life."
You could have the character try to anticipate and write about the things that may (or may not) happen after their death (post-mortem etc.) in the period (hour/day/whatever) leading up to that point. They can't really know what will happen and so it'll just be speculation, but it'll be based on their character traits, the arc of the story, your needs (as a writer) etc. and so will be as accurate as it can be.
One way to indicate that they are dead is to switch backwards and forwards between the scene on the slab and the events leading up to the death.
Done this way you will sidestep the ghost/afterlife scenarios and yet still get to talk (in 1st person POV) about the things that matter in your story.
Good luck with the project - sounds interesting.