RelexCryo said:
Because he needs to save Peach. Peach is someone he cares deeply about and needs to rescue.
No, he doesn't "need" to. Peach (in the vast majority of her iterations, anyway, I can't speak to things like Mario RPGs) is an arbitrary game objective. We never know why she's this, or even any specifics of Mario's relationship with her. Because we don't need to. Characterization is not what's going on. Same with most other arbitrary game objectives; you're told a thing is happening or must be done and plopped into an avatar that does it. "X-Men!! Go, and save the city!!" It's not characterization, it's an excuse to indulge the game mechanic.
(The examples in the latter half of your post are more false parallels. You mistakenly seem to imagine that if a game mechanic does something vaguely or remotely similar to a thing that happens in fiction, this makes the "characters" equivalents to those in literature. Again, I think you just are having trouble accurately synthesizing and comparing information here, in much the same way as you appear to simply not know what a "cardboard character" is.)
Your answer implies a basic lack of understanding about videogames in general.
Hiss-hiss, now, no need to get petty about it. FWIW I think there's the germ of some genuinely interesting thinking about game mechanics, characterization and interaction in what you're saying. And like I've said, there are instances of real characterization in gaming. Unfortunately right now you're just too focused on defending a fallacious and uninformed equation of game characters with all other characters to have useful comparative insights. I'd urge you to keep working at these ideas, but toss out that preconceived notion and do some more reading.
And for God's sake get rid of whatever checklist they used in that horrid "Accelerated Reader" program you talked about and go find some real textual analysis. For some close analysis of Shakespeare's characters, for instance (which is a good place to start) get some critical editions of his plays or put them on your Christmas list (Hamlet and Romeo & Juliet are good places to start). A great place to start for literary criticism is Eric Auerbach's classic
Mimesis, which spans almost the whole history of Western literature.