The finest defense of character is correct action. Acquaint yourself with virtue, and you can expect proper treatment from those around you.
The more limitations you put on a character often times the better a character you'll make them, the more interesting the story becomes because the character can't simply wave a hand and make something happen. They have to work within the framework.
The number 1 thing that I don't want to see in a story is when characters exist simply to be proven wrong.