heroism

Yes ofcourse the success of a film depends on the hero a lot. Most of the people see a movie because of the hero who is acting in the film.

Yes, it often does. The main character or hero is the one that the audience is usualy made to like as the main character/hero are the ones who are in the movie from beginning to end. IF the hero has starred in a previous one of their films, their second movie is usually as much or more puplar than the first.