Mario Vs. Sonic.

[Gors]

In Mario's case, he was designed to be an all-purposes character (which is obvious seeing all the spin-offs, games and media he has appeared in). But in the start, the developers could bestow him any kind of role in the game: he could be the hero, like in Donkey Kong, or the villain, in Donkey Kong Jr.

But as people started liking him more, and the Mario franchise became a huge success, it limited Mario's roles (developers couldn't put antagonist roles on him anymore, because his personality and attitude solidified as a virtuous hero. This could also be why Wario has enjoyed success too, as he is a kind of 'Mario' that can play any roles, because of his behavior.

For Sonic, he already had the 'cool & edgy' attitude since the start to confront the kindness of Mario (after all, kids are generally interested in things that look cool). People knew he was a good guy, but wasn't a happy-go-lucky man either. Though in recent games, things got weird and all that (I didn't play any of the recent Sonic games enough to talk about it).

Just felt like saying stuff, I don't think it really adds to the discussion whoops