Board Thread:Questions and Answers/@comment-34369352-20190812144928/@comment-26533608-20190812182542

Depends on what you would consider a Mary Sue.

In my opinion, a Mary Sue isn't just a perfect character. You can have - subjectively, mind you - 'perfect' characters in fiction. A Mary Sue is a character whose 'perfection' detracts from the story. Overpoweredness is completely fine, but it has to be there for a reason, there needs to be a good explanation as to why a character has it, and not just for the sake of a power-fantasy. Another common trait in Mary Sues is that the entire universe is built around them, and that they are not bound by the rules of said universe.

In my opinion, personality isn't really a factor in determining Mary Sues. You can have Mary Sues without much personality at all (the typical one), you can have excessively angsty Mary Sues, and you can have Mary Sues who are complete assholes. They're all Mary Sues, characters who twist the rules of their universe to their benefit.

Relationship-wise, depends on any other characters in your headcanon. Many Mary Sues will have people randomly act against the way they usually should and side with the Mary Sue, and the character who only exists to hate on said Mary Sue. Like I said, entire universe built around [the Mary Sue].

There are also all the variations of Mary Sue, such as the Purity Sue (the naive one), the Jerk Sue (self-explanatory, the edgy asshole one) and the Sympathetic Sue (the one who has an excessively tragic backstory (or as TVTropes calls it, Deus Angst Machina) for the sole reason of trying to get the reader's sympathy).