A Mary Sue is, according to Wikipedia, “a fictional character with overly idealized and hackneyed mannerisms, lacking noteworthy flaws, and primarily functioning as wish-fulfilment fantasies for their authors or readers”. In other words, a Mary Sue is a character who is ‘too perfect’, or, an ‘authors pet’.
There are many types of ‘-sues’. Mary Sues, Villain Sues, Anti Sues and even Marty Stu’s. I’m sure there’s others, but I’ll just run through these.
Mary Sue: As you know, a Mary Sue is a character who is perfect in every way. Think blond hair, blue eyes etc. They have no flaws, no scars, and are most likely very beautiful and smart. Everyone likes her (or him. Male Mary Sues can be called ’Marty Stu’, or ‘Garry Stu’). Probably the most well known Mary Sue out there is Bella Swan, from the Twilight series.
Villain Sue: My first thoughts on a Villain Sue was that they were stereotyped villains. However, a Villain Sue is a villain with the following traits: Defeat characters with ease, don’t kill characters when they have the chance (wanting to see character suffer, to gloat, or have all the characters captured at one time), has a tragic past, which is supposed to justify their bad behaviour, or secretly having good qualities.
Anti Sue: In an attempt to not create a Mary Sue, some writers will create Anti Sues. An Anti Sue is the exact opposite of a Mary Sue. They will most likely have a physical or mental illness, be unattractive, disliked by the other characters, and cowardly.
There’s three types of ‘-sues’ for you. It’s important that you don’t have a ‘-sue’ (lets just call them Mary Sues for the rest of this article) in your writing, because Mary Sues are considered unrealistic and two dimensional characters.
But how do you know if your character is a Mary Sue? Have a look at him/her. Is the character perfect? Does the character have no flaws? You can also take a ‘Litmus Test’.
There’s heaps of these tests on the internet. Just google ‘Mary Sue Litmus Test’, or something like that. When I first discovered Mary Sue, I took a test. I haven’t compared tests, but I took this test, and was pretty happy with it. It was detailed, although I didn’t understand some of the answer. But I understood enough to know that my MC, Lily Ashwood, is kind of like a Mary Sue. But not quite.