Gary Stu and you, a formal test.
On a whim, I went to the Original Fiction Mary-Sue Litmus Test (found here, http://www.ponylandpress.com/ms-test.html), and put Yuugi from Yugioh, Judai from Yugioh GX, and Yusei from Yugioh 5Ds through it. The results?
Yuugi: 40, which marks him as a Gary-Stu.
Judai: 75, which marks him as an Irredeemable-Stu
Yusei: 79, same as Judai.
Now, I've never cared much for these sorts of tests, as the answers are all in isolation without any sort of context, and the scale on the scores is just really incredibly strict, you can have maybe one or two significant traits on the character before it starts calling it a sue/stu. But even so, I think that these results are rather telling. And this is just on the universal test, I'm pretty sure that if I were to find a more specific test, like one for Anime in general, or even the Yugioh franchise in particular, the results would be even more glaring. Just a bit of fluff for thought.
Yuugi: 40, which marks him as a Gary-Stu.
Judai: 75, which marks him as an Irredeemable-Stu
Yusei: 79, same as Judai.
Now, I've never cared much for these sorts of tests, as the answers are all in isolation without any sort of context, and the scale on the scores is just really incredibly strict, you can have maybe one or two significant traits on the character before it starts calling it a sue/stu. But even so, I think that these results are rather telling. And this is just on the universal test, I'm pretty sure that if I were to find a more specific test, like one for Anime in general, or even the Yugioh franchise in particular, the results would be even more glaring. Just a bit of fluff for thought.