Therin of Andor wrote:
I'm not sure why you insist a Mary Sue has to be a guest star, since even the original Mary Sue was the star of the fanfic story that originated the term.
But wasn't she the guest
main star in a Star Trek fanfic, with Kirk Spock and McCoy the regular players? Or did Paula Smith write all of her ST fanfics about the girl?
Well, you can read the entire (rather short) story
and draw your own conclusions.
I agree with Mr. Governo, that self-insertion in somebody else's milieu is the characteristic property of a Mary-Sue, and with "rahullak," that even though the trope originated with a character created as a parody of bad writing, it doesn't necessarily follow that a well-written Mary-Sue character can't exist (and indeed, I regard Piper as a defining example of a well-written Mary-Sue).
Thanks for the note of agreement!
I also agree that, despite its etymology, "Mary Sue" doesn't necessarily have to come with a negative connotation. Much like "canon" (to reference another current thread about terminology), the term can be used descriptively without suggesting on its own that a character is well- or badly-written.