Without any other information on your game, it's difficult to give you advice. Just avoid as many tropes as you can (like the black guy who always dies first), and build your characters according to the world they live in. What I mean is, it would be silly (though hilarious) to have Viewtiful Joe-like characters in a world like The Last of Us. Need any spare writers? I could lend you guys a hand if you need to, or just for the extra point of view.