A Mary Sue is a type of fictional character, usually a young woman, who is portrayed as unrealistically free of weaknesses. Originating in fan fiction, a Mary Sue is often an author's idealized self-insertion. Mary Sue stories are often written by adolescent authors.

What is a Gary Stu character?

—Introduction of Spidey3000. Gary Stu, also called Marty Stu, Marty Sam, or Tom Sue, is the male counterpart of Mary Sue. Largely due to the fact that fanfic writers are more often female than male, Gary Stu is far less common than Mary Sue.

Can a villain be a Gary Stu?

An evil Mary Sue/Gary Stu can potentially become an unstoppable force of nature, something I find quite interesting in a story centered around the villain.