Everywhere she goes people bow down before her beauty, skill, perfection, and all around awesomeness. Those few who manage to get her in bed all claim it was absolutely completely divinemind-blowing sex. The canon heroes all treat her as if she was the second coming of Christ. When ever any enemies attack the heroes are usually rendered completely helpless and Mary Sue comes in with her Blade of the Dragon God and eliminates the enemies with out breaking a sweat. She then proceeds to head to the lair of Emperor Evulz and destroy his minions with her allpowerful magic and then strike down the Emperor in a curb stomp battle. After which she proceeds to slaughter all the prisoners and slaves in the emperors castle then massacre everyone in the castle town on the justification that they MIGHT have sided with him.
The canon heroes never call her out on this and instead worship her for this saying it was the right thing to do. The one character who doesn't is looked down upon by the others until they, eventually comes around and worship Mary Sue like everyone else. She then takes control of the empire and uses it to found Mary Suetopia and rule it as a goddess forever. See also: Thirty Sue Pileup
Downplayed: Sue is great at a lot of things and is the most well rounded, emotionally stable and mentally functioning member of the cast, but they're mostly a supporting character a best, whose main contribution is the occasional Rousing Speech or telling The Hero an old tale from their many travels that helps them accomplish a certain task, serving the plot mostly by being The Heart or The Ace.
The character discovered the secret to perfection.
The character is a Reality Warper who modes and shapes reality to its/her/his liking.
A character with few-to-no positive traits, intended to be as unlikable and as much of a failure as possible, who nobody likes.
Marietta appears in the fan fic intended as comic relief, including her infatuation with Bob the Strong. All the readers find her funny, charming, and intelligent and think that without author manipulation there's no way that Bob would not have seen that she's much better for him than the vain and lazy Alice — but the author does not perturb the canon pairing, even though Bob has no reason not to prefer the better woman.