I'm currently watching the first season of GX; at what point does he stop being such a Marty Stue and starts losing? Beating Crowler, beating Chazz (technically he did), then beating Alexis (Alexis had no business losing that duel), beating Jinzo, the kid with Moki Moki, the girl who's in love with Zane, the Paradox Bros, beating Bastion, then Chazz again (so where did he get those three kids that special summon each other and why is this the first duel where we see them?). He has only lost to Zane, who's allegedly the best duelist in Duel Academy and he even put up a good fight there. I know he's the protagonist but good Lord, for me it's doing the exact opposite of rooting for him. The Alexis and Chazz (#2) duels were ridiculous.
It's not that Jaden is a mary sue (Only main character I can call a Mary Stue is Yusaku. I could see an argument for why Yusei is a Mary Stue though.) it's that Yugi was such a flawed protagonist that it makes Jaden look like a Mary Stue in comparison. (Worst Duel Record of all other Protagnists, one of only two protagnists (The other being Yuma) who couldn't duel by themselves ...
It becomes a problem when they're trying to create suspense. Like, ok, am I supposed to believe that that gravekeeper is going to bury Jaden and his friends alive? Am supposed to believe Armed Dragon lvl 7 is going to directly attack Jaden and the duel is going to end right at the beginning of the next episode? It's all about writing. But it's an anime, who cares, I guess.
The only YGO character that could qualify as a Gary Stu is most definitely Yusei, pal. Literally card Jesus. Yusaku is still fresh and we still haven't seen him develop a lot. But I'll admit that so far he's made a lot of asspulls, especially against Revolver.
I’m the manga he doesn’t use elemental hero he uses masked hero’s ands planet card. Which is the main story in the manga I wish they’d make a real masked hero card released he had main deck masked hero’s in his deck