I think that Silvio began as a petty person. He challenged the Count to a duel because he was jealous of him, but he does not kill him because he sees that the count does not care that he might die. When Silvio goes into to hiding he does not become a hero, but i do agree with David and Mike that he becomes a man of morals. He returned to kill the Count but he ended up proving the point he wanted to prove and he left it at that.