The term 'Mary Sue' originates from poorly written fan fiction or original characters that are made to be perfect, flawless, a lover to all who gaze upon her looks, and tattooed with on her forehead these words "Cliche." It can be seen that most 'Mary Sues' are self-inserts of the author or artist into a series, this practice is often seen in the "Harry Potter," "Homestuck," "Adventure Time," and "Naruto" series. These characters tend to be over the top with a cliched tragic past and having the main character falling in love with her whilst other male (or even female) characters going into heat for her. If you're roleplayer, please try avoiding these symptoms with your OC at all times even if you wish to please the readers with a so-called "epic" or "awesome" or "original" characters.
"Mary Sues" tend to fall into the scene or gothic group as we can note that from a very famous trollfic, "My Immortal," with the infamous heroine, Ebony Dark'ness Dementia Raven Way. I wouldn't bother to read this trollfic if you aren't interested in Harry Potter but do take a glance to see how the world turned upside down from fangirls and fanboys. The term for the opposite sex is "Gary Stu" and the follow the same outlines that a "Mary Sue" does.
Good luck and please refrain from venturing into that side of the World Wide Web,
-Soar.
