>>21988075No.
A Mary Sue would be a self-insert character, in fan fiction, a Mary Sue would be a transparent author self-insert, that's inexplicably liked by all, regardless of either plain, or atrocious personality.
Another way to look at it is a character that's absurdly perfect, an example would be Drizzt from the Dungeons & Dragons setting, this can often be coupled with a completely unlikable personality that is yet adored/desired/liked by every other character, like "Enoby"
That's not to say that self-insert characters, author or otherwise, are necessarily bad, a good example would be Sengoku Rance, which is written by a woman, and she has written a self-insert character for herself in the story, Rance being an ideal that she's designed for herself.
