Marvel Cinematic Universe: 10 MIA Villains Who Need To Return
9. Helmut Zemo
Last Seen: Captain America: Civil War
Two years before Thanos managed to defeat the Avengers and wipe out half the universe, Helmut Zemo managed to split our heroes right down the middle in Captain America: Civil War, putting Tony Stark and Steve Rogers at odds with one another in a way that left the group torn apart and vulnerable. He didn't have to don a costume or throw a punch to make it happen, either, making his actions all the more impressive.
Though his plan was meant to end with the taking of his own life, Black Panther prevented him from doing so so that he could face judgment and imprisonment, the former Sokovian soldier last seen contained and content about his overall success. And while his story could fittingly end there, it's hard to imagine he'll be too happy about the Avengers' failure to prevent The Decimation, just as he blamed them for what Ultron did to his home and to his family.
In Marvel Comics' history, Zemo is also known for forming one of the several iterations of the Masters of Evil, an appropriately-named group of evildoers. It'd be interesting to see the MCU's version of the character putting his mind to work in order to bring together villains from the overall franchise in an attempt to take on the Avengers again following their inevitable reassembling by the end of Avengers: Endgame.