Superheroes have conquered Hollywood. They generate billions of dollars at the box office and have pushed other movies to the margins. That revolution has been led by Marvel Studios.  In a new four-part series, WSJ’s Ben Fritz goes behind the scenes and reports on how Marvel, a once-troubled comics publisher, soared to the top of the movie business. It’s a tale of rivalries, spite, little-known deals and incredible luck.  Learn more about your ad choices. Visit megaphone.fm/adchoices