LOS ANGELES, May 3: Scarlett Johansson first joined the Marvel comic book superhero universe when she was introduced as the mysterious Black Widow opposite Robert Downey Jr in the 2010 blockbuster “Iron Man 2.” The action-filled movie role marked a big change for the actress, who’s known more for low-key performances in films like Sofia Coppola’s drama “Lost in Translation” or Woody Allen’s sly comedy “Vicky Cristina Barcelona.” (agencies)