First I debated what "affected" meant to me, then I started bell-curving them based on the weight of my first answer, then I had to call Chris to see if she had the parts of my brain I hadn't been using.
So, not as finished as I would have liked, here is my
What five character deaths affected you the most?
I'm going to hold each fandom to one place, or (no surprise) there would only be one real answer.
1) Boromir (Lord of the Rings)
The most meaningful and least arbitrary death I've ever encountered in fiction. (not to say I haven't written him un-dead in various ways in my private heart)
Part of my absorbing this mythos is probably that I read it at exactly the right moment for me. Part is the Timelessness.
On top of Boromir's own story, I have him so tangled up in my head with that summer where Chris and I would drive an hour once or twice a week to see FoTR on the big screen, playing Dave Carter's music all the way in an effort to come to grips with all the pictures on our heads. Then, suddenly Dave was dead, and he was even more tangled up in the mythology. I'll never unravel it now.
There is hardly a death in this work that leaves me unaffected. When Hama is hewed down at Helm's Deep, when Halbarad falls on the Pellanor, when Hirgon's headless body is found still clutching the red arrow... there are no minor characters for me.
2) Hoban 'Wash' Washburne (firefly)
The most arbitrary and possibly useless death on my list (though I'm still sorting it out in my head) Honestly, the movie screws with FF's mythology enough that Chris wishes she could go back and never watch Serenity since it nearly ruins the series for her now.
Wash not only affects me for himself, but his death also does away with Zoe+Wash, which is actually worse for me. And as the pilot, he is almost part of Serenity for me, and I was, right up to the moment of Wash's death, afraid we were going to lose *her.* (I've always been a ship girl, what can I say...)
3) Which brings me to my ship death - The exploding of The Grissom in Star Trek III. Too much tangle here for me again - Gus Grissom was an early fixation of mine, and his death on pad 34 remains brand new in my heart. And, it was much much too soon after the Challenger disaster for me to deal wth those visuals.
4) Again, not a person, and not a single incident - but everything in Silent Running from the moment Freeman Lowell chokes up telling Huey and Dewey: Poor Louie, God bless him... he's not with us anymore... to the explosion of the Valley Forge, filling the screen over my head in the dark theater.
5) The death that is and isn't - that is to say, Hades. It occurred to me when I was young that Persephone went back every year because she loved him, and it changed the basis of my own mythology.
Harris and Hagman going back to die in Sharpe's Waterloo. I'm a Harris girl anyway, but that moment when they turn around? Gah.
I avoided anime answers here, though I have some. I couldn't settle on which to pick - maybe I'll get into that sometime....
And since Historical Fiction is a fandom for me, Henry II. I know he's lost everything that made me admire him when he was young by the time he dies, but I get caught up in those last words: “Shame, shame on a conquered king”.