Who are the Most Memorable Characters in Science Fiction, Fantasy and Horror?

Mike Resnick starts off an interesting conversation about the most memorable characters in genre fiction over at SfSignal. However, please also read the answer by Adam Roberts, who hurls down a gauntlet at the conventional notion of characterization, and proposes a modernistic theory, following the inspiration of Joseph Conrad. Agree or disagree, it is worth a read.

My opinion? Of course I have an opinion, you whippersnapper! That is why they call it ‘opinionated’. And go get a haircut and a job!

I can think of a plethora of characters who are memorable because of the book they are in: Paul Muad-dib or Jommy Cross spring to mind, or Hari Seldon: but in these cases, I do not think the character in and of himself is what makes him memorable, aside from his setting.

The deeper question here is what makes for great character? There are two (or more) opposite influences at work: the romantic school holds the character should be iconic and archetypal, almost demigodlike, and the realistic school holds the character should be quirky, complex, three-dimensional, and human.
So allow me to separate the questions and answer them both.
1. Which characters are the most memorable of the realistic school?
Patera Silk from Gene Wolfe’s LONG SUN books — I have never seen a fundamentally good character portrayed, warts and all, with such complexity and such moving realism.
Severian from Gene Wolfe’s NEW SUN books — I have never seen a fundamentally complex character portrayed, warts and all, with such goodness and such moving realism.
Gene Wolfe, indeed, is the only author I have ever read whose character all speak with such distinctive mannerism and voices that he never need identify who is talking: their speech patterns identify them.
I strain my brain to remember some other books who have characters are quirky, realistic, three-dimensional and distinct as any character from Gene Wolfe, even a minor character, like an old man who once knew a painter named Fetchin. Sorry, folks, I cannot think of a one.
2. Which characters are the most memorable from the iconic, demigodlike school?
Naturally, this list is almost all space opera or fantasy, since realism does not lend iteself to iconic, demigodlike characters:
Kimball Kinnison from the LENSMEN books of Doc E E Smith — this man is the epitome of the science fictional idea of a super-soldier, super-spy, super-scientist, super-boy-scout, super-hero. When I came across a line in a Heinlein book, "Muscled like the Gray Lensman" I knew exactly what was meant. Kimball Kinnison, simply put, is the Greek God Apollo.
Marc C. "Blackie" DuQuesne from the SKYLARK books of Doc EE Smith — the man is the epitome of the science fictional idea of a super-villain, cold as a machine, mercilessly logical, brave, methodical, and yet there is something to admire in his twisted and selfish moral code. He falls for Stephanie at the end of the book, and flies away planning to conquer and rule another galaxy. He’s big.
Gandalf the Grey — the very definition of a wizard.
Kerth Gerson from the DEMON PRINCES books of Jack Vance — the Count of Monte Christo in Space. His villainous opponents are not less memorable than he: Malagate the Woe, Kokkor Hekkus the Killing Machine, Viole Falushe the sybarite, Lens Larque the brutal egomaniac, and, worst and best of all, Howard Alan Treesong, the chaoticist.
Mr. Spock from STAR TREK — When you want to describe someone was logical and stoical, you say ‘he is like Mr. Spock’ and everyone knows who you mean. The fact that he fights his human and emotional side makes him a suffering Promethean figure. Speaking of which…
Baron Victor von Frankenstein– Come now. Even the name ‘Frankenstein’ refers to the stone of the Franks, a reference to the Philosopher’s Stone which can animate life from non-life, is the modern Prometheus. He is the literary archtype of every mad scientist who dares the unthinkable.
Corwin of Amber — He is the very picture of the antihero of intrigue, if it is a Film Noir picture, that is.
Aslan from Narnia — Aslan is Jesus in a lion suit. You don’t get much more iconic and godlike than that.
Conan the Barbarian — Conan is Mars, the war-god.
Elric of Melnibone — Elric is the anti-Conan, frail where Conan is brawny, over-civilized where Conan is barbaric, and so on. Whining, self-absorbed, self-pitying, Elric is remarkably memorable, not likely to be mistaken for anyone else. Elric is Hamlet.
Lazarus Long — The quintessential curmudgeon. Lazarus Long is H.L. Mencken.
Tweel or Tweerl — That alien birdlike thing from A MARTIAN ODYSSEY by Stanley Weinbaum. ‘One-one-two—yes!—Two-two-four—no!’ Even after all these years, still one of the most convincely unmanlike aliens in the literature.

Not some, but MOST scifi and fantasy stars one avatar or another of these various demigods clashing and dancing with each other: the superscientist, the supervillain, the messiah figure, the wise old man figure, the mad scientist figure, the war-god, the film noir tough-guy, the Promethean figure (either light or dark), the doubting Hamlet figure, the cynical Mencken figure, the Count of Montechristo, the alien. These sum up the hopes and doubts and dreams we have about the future.
These are the memorable characters of science fiction because they are the ones everyone remembers to copy.