Mary Sue, Marty Stu

[Esquilax]

This guy! This motherfucker right here!

Kirito, the protagonist of Sword Art Online, is possibly the most blatant Marty Stu I've ever seen in a completed, popular work. He's the strongest, fastest, most skilled fighter in the entire series, he's got special weapons nobody else has, he can even dual wield, which is a skill only he possesses and the story makes a big deal out of as this unique technique. Any woman he meets will fall in love with him, and he has the second strongest character in the series, a hot redhead, hanging off his arm. In fact, the entire second half of the first series was devoted to a weird male power fantasy where he has to rescue that same woman (she's his prize, a lot of the time) by enlisting the aid of a bunch of other hot women... all of whom seem totally willing to bone him.

What really tips the scales, to me, is that even when he does absolutely wrong things, the narrative voice still portrays them as being good, like the guy can literally do no wrong. When he fights the final villain of the first series, he deliberately constructs a situation that allows him to indulge in some cold blooded torture for absolutely no reason other than to watch the villain suffer, and the entire thing is framed in heroic shots and pumping music. It just comes across as gross.