>>101142592>marysues by default are fan creations
If you subscribe to the belief that all modern pre-existing IP comics, cartoons and movies are just fan creations that get paid for it, then it’s easy to see some canon characters as Mary Sues. Rey for example, is a fan-made character, inserted into Star Wars canon and quickly rose up to surpass all her predecessors and enemies with no training whatsoever. And similarly acquired pre-established characters as allies with absolutely no effort.
That said, Batman is not a Mary Sue, because he’s typically depicted as an unlikeable asshole in-universe. He has allies, but he beefs with them often, and he has a tendency of getting his loved ones murdered by association.