How can a reader tell when something written in a work of fiction represents the author's viewpoint and when it is merely dialogue the author is using to represent the viewpoint of his characters?
That's a tricky question to wrestle with, and, personally, I don't see any reason to ever assume the latter over the former with any degree of confidence.
That said, when an author has three very different characters use the same increasingly rarely used, no longer socially acceptable, completely un-PC term three times in the same relatively short story? Well, that at least can make a readers suspicious of the author.
I bring this up because I just read a trade paperback collection of Superior, the 2011, 7-issue Leinil Yu-penciled series that Marvel Entertainment published on their creator-owned/keep-Bendis-and Millar-happy-at-all-costs Icon imprint. It was written by Mark Millar, no stranger to having folks arch their eyebrows at the words of his narrators and characters and getting uncomfortable about the degree to which the characters speak for the author.
If you haven't read it—and you needn't—Superior is either a rejected pitch for a Superman comic that DC didn't like as much as Millar's Red Son, or it's an idea for a Superman story that Millar had but realized if he just changed some characters and costumes (here, extremely slightly) as he did with Wanted, he could get away with using DC characters for another publisher, and reap the financial reward of the book and/or the movie adaptation. (This isn't a review of the book; I'll get to that in the near future, but this one aspect struck me as so strange and made me so uncomfortable, I thought it worth noting in its own post before proceeding to the formal aspects of the comic and assessments of the overall quality).
This is the narrator of the book, the Lois Lane character Madeline Knox, who starts narrating about half-way through the first issue, but isn't actually introduced until this scene in the third issue:
In her defense, she does tell the reader, just two pages prior that, this scene takes place "Back when all I cared about was how much I weighed and what my ratings were...I don't think I was a very nice person back in those days."
No, she doesn't seem like it, and I suppose ranting and raving about "a retard convention" is a decent shorthand to prove just how not a very nice person she was "back in those days" (a strange turn of phrase, since the point in time she's narrating from is just a few weeks later).
Here's another character in the book from a big "twist" scene a few issues later. He's Ormon, and he is a (spoiler, if you do wanna read this book and experience as its writer intended it to be read) demon from hell:
Here's another character from the book, an actual 12-year-old boy, although through the infernal powers of Ormon he's been transformed into Superior's arch-villain Abraxas (While the word "Abraxas" has origins that pre-date comics by centuries, it's worth noting that both Marvel and DC have villains named Abraxas; the DC version spelled his name "Abraxis" and appeared in 1992's Armageddon: Inferno, while the Marvel one appeared in a Fantastic Four annual from 2001):
Anyway, three seems a lot for a comic book published in 2011.
*Now that I think about it, maybe he's not 500-years-old, but merely hasn't been able to convince anyone to sell a soul to him in 500-years, and he's actually the same age as all demons; the comic doesn't get too deep into demonic biology or the cosmic origin of angels and demons or anything.