So What's A Mary Sue, Anyway?
A Mary Sue is a character (male, female, or otherwise) who is given or is expected to be given unwarranted preferential treatment and unearned respect, thereby compromising the integrity and believability of the story and/or its characters.
A hallmark of the Mary Sue is that xe will have few, if any meaningful challenges, hardships, or handicaps. Obstacles that exist for others are virtually nonexistent or pose little to no challenge for a Mary Sue. In fact, it'll often seem that the very fabric of the universe is bending to accommodate the character. For example:
- Characters who are normally grouchy or hostile will immediately be able to sense the innate goodness/specialness of the Sue and will warm right up to xir.
- Characters who have enemies that want them dead and/or are in possession of highly-coveted knowledge/items will trust Mary Sue almost immediately, sometimes after a token life-saving courtesy of Mary Sue. They will not take reasonable precautions in the event that the character is an infiltrator sent to kill or steal from xir.
- Enemies and rivals of Mary Sues will be defeated quickly and easily, or will pose no serious threat. In essence, Mary Sue's foes are straw men and paper tigers.
- Non-canon friends and family members are virtually nonexistent, thus freeing up their social schedules for the canon characters they want to hang out with - who will have conveniently, even miraculously free schedules to hang out with the Mary Sues.
- Other characters in general will be inordinately fascinated with the Mary Sue, even to the point of obsession.
- Essentially, genuine Mary Sues are the spoiled pets of the writer: whatever the character wants or needs - be it power, wealth, prestige, or a lover - it comes to the character with ridiculous ease, even to the point of blatantly contradicting previously-established rules.
- With roleplaying characters, the player may not necessarily start their character out with these things, but it will soon become apparent that the player expects everyone else to accommodate xir character thus.
Mary Sues rarely, if ever, have to deal with realistic consequences to their actions.
A few hypothetical examples:
- As a student, Mary Sue attended wild parties rather than study to the point that in real life, her grades would have suffered terribly. Mary Sue's ability to get into college or find a good job is never affected - or, it will never become necessary or relevant that Mary Sue enters college or gets a good job.
- Mary Sue openly insults Poppy May, who is a longtime friend of Billy Bob. Billy Bob, who only met Mary Sue two weeks ago, won't even care that Mary Sue has insulted his longtime friend and will go on loving Mary Sue all the same.
- Mary Sue lights off explosives inside Poppy May's kitchen as a "joke." Despite the fact that this would cost hundreds, if not thousand of dollars to repair and Poppy May's already struggling with two jobs as it is, Billy Bob will think it's funny and that Poppy May "deserved" it. No-one will call the police on Mary Sue, let alone press charges.
- Mary Sue was once the Big Bad's most loyal follower until xir heel-face turn. Once Mary declares xir intentions to leave the villains and join the heroes' side, no-one of any importance will seriously consider the possibility that xe may still be working for the Big Bad as an infiltrator/mole.
- Before xir heel-face turn, Mary Sue did serious harm to the other characters, people the other characters would care about, and/or their property - yet afterward, all is forgiven and no grudges are held by anyone who matters. Mary is never held legally accountable when xe should be, and the issue may never be brought up again at all.
Very often, Mary Sues are created for the readers to admire, envy, or pity rather than empathize with.
This is basically an offshoot of the "unearned respect" problem - the writer/player expects everyone to think their character is awesome and worthy of admiration or respect. This type of character is nothing new - Puritan literature frequently featured too-good-for-this-sinful-Earth heroines who were created as role models to Puritan children. You've probably heard the expression "Little Goody Two-Shoes," which is frequently used to refer to someone who acts in a sanctimonious manner - this was originally the name of one of these heroines.
Mary Sues don't just happen in fanfiction.
Original authors have created characters who are considered just as bad as those created by fanfiction authors - take Wesley Crusher, Bella Swan, Edward Cullen, Rayford Steele, and Buck Williams, for example.
Mary Sues aren't just characters you don't like, nor are they simply love interests thrown in out of left field.
With a genuine Mary Sue, you'll feel like the writer is constantly trying to rub your nose in how awesome, special, or virtuous the character is. Mary Sues are often involved in poorly-developed relationships, but not all characters in poorly-developed relationships are Mary Sues. Genuine Mary Sues bend the fabric of their universes to accommodate them and give them what they want.
Mary Sues aren't simply strong and/or talented female characters.
If a female character annoys you, ask yourself a simple question: would I find the character equally annoying if she were male? If the answer is no, then the character probably isn't a Mary Sue.
Before declaring a character that isn't yours a Mary Sue, or if you get people declaring your Mary Sue character for questionable reasons (eg, the character is simply a powerful female)...
Please see/show them Before You Go Declaring Other Peoples' Characters Mary Sues...
The Universal Mary Sue Litmus Test
Mary Sue Subtypes
So You Want To Have A Powerful Or Talented Character Who Probably Won't Be Perceived As A Mary Sue?
Basic Tips To Improve Your OCs & Fan Characters
Tips To Create Better OC Relatives of Canon Characters
Basic Tips To Write Better (And More Likeable) Badasses
Common, Yet Terrible Character Descriptors - And How To Fix Them (And Write Better Descriptions In General)