A Mary Sue is a character archetype in fiction, usually a young woman, who is often portrayed as inexplicably competent across all domains, gifted with unique talents or powers, liked or respected by most other characters, unrealistically free of weaknesses, extremely attractive, innately virtuous, and generally lacking meaningful character flaws. Usually female and almost always the main character, a Mary Sue is often an author's idealized self-insertion, and may serve as a form of wish fulfillment. Mary Sue stories are often written by adolescent authors.
Originating from fan fiction, the term Mary Sue was coined by Paula Smith in the 1973 parody short story "A Trekkie's Tale", as the name of a character standing in for idealized female characters widespread in Star Trek fan fiction. The term has been applied to male characters as well, though a male character with similar traits may be labeled a Gary Stu or Marty Stu.
As a literary trope, the Mary Sue archetype is broadly associated with poor quality writing, and stories featuring a Mary Sue character are often considered weaker for it. Though the term...