Who is Ultron?
At Comic-Con 2013, Joss Whedon appeared on stage at the Marvel to show a quick teaser trailer that revealed the title of 'Avengers 2' - 'Age of Ultron.' The Comic-Con crowd went nuts but for those who are unfamiliar with the "Age of Ultron" crossover event in the Marvel comic books, we present a quick primer on the upcoming supervillain in 'Avengers 2.' Who is Ultron? Let's find out!
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