Board Thread:Off Topic/@comment-25396609-20160319212213/@comment-26397825-20160320041426

A good Mary Sue test is this one. Like I said, it's very subjective and we can't really get a feel for it based on reading a small blurb about their interactions with the main cast unless we read the actual story. Most of the time it's up to the creator themself to determine if the interactions with the main characters make them a Sue, but tests like that one can help.

A lot of us just prefer to avoid adding it to our character sheets as it implies that the relationship existed before the start of the story. If they meet the main characters along the way as a natural progression of said story, then it's a lot less Sueish.