Joss Whedon Announces "Avengers: Age of Ultron" at Comic-Con

Warner Bros.' Batman-Superman flick wasn't the only big announcement made Comic-Con this week. From the other side of the ring, Marvel is packing a punch with director Joss Whedon's announcement that " The Avengers" sequel would be titled "The Avengers: Age of Ultron."

The title came as a surprise to Marvel superfans, as the end of "The Avengers" seemed to set up an epic struggle against the supervillain Thanos in a potential sequel. Instead producers have whipped up something else from the extensive Marvel catalogue. Ultron, described as a genocidal robot, is an artificially intelligent creature who becomes one of the Avengers' greatest enemies.

"Avengers" heavyweights Robert Downey Jr, Jeremy Renner, Chris Hemsworth, Chris Evans, Scarlett Johansson, Samuel L. Jackson and Mark Ruffalo will all be returning to the big screen. You can expect to see them battling Ultron in theaters by 2015.