First appearance: Iron Man 2 (2010)
Last appearance: “All Hail the King” (2014)
Justin Hammer (Sam Rockwell) was initially meant to simply be both a business and personal rival to Tony Stark in the second Iron Man, and, as such, he’s never had any kind of real extension to the greater
Marvel Cinematic Universe; once he played his role, he was disposed of by being left to rot in prison. Case closed.
What makes the character stand out so much is the sheer brilliance Sam Rockwell displayed in bringing the minor part to life – Hammer just exudes personality, and that’s saying a lot, given the eclectic (and, at times, melodramatic) mix that Marvel continues to bring to bear across all its properties. This is the sole reason why Justin was brought back for a quick cameo in the Marvel One-Shot “All Hail the King,” and it’s why we’re so desperate to see him come back yet again.
And lest you think it might be too difficult to reintegrate such a minor character, it turns out that Luke Cage has already done the preliminary work: Hammer Industries has been secretly reverse-engineering leftover Chitauri technology from the Battle of New York and designing brand-new Terran weaponry with it. That’s a pretty good foundation for future (mis)adventures.