Captain America: Civil War looks as though it is going to be an enormous movie. While all everyone can seem to talk about is the impending showdown between former allies Steve Rogers and Tony Stark, people seem to have forgotten that remnants of Hydra will also join the fray -- led by the villainous Baron Zemo (Daniel Brühl) to wreak havoc on Captain America's life.
One of those remnants is none other than Crossbones, a.k.a. Brock Rumlow (Frank Grillo), who will evidently stop at nothing to exact vengeance against Cap for the fate that befell him during the Star-Spangled Avenger's second solo outing, The Winter Soldier.
"... if you've seen The Winter Soldier, Brock Rumlow was in bad shape and that was because of Cap and he’s not happy. I tell you, coming back as Crossbones, his alter ego, he is not a happy guy and there’s nothing that is going to get in the way of him doing what hes setting out to do. Which I can not tell."
So, it looks like Rumlow blames Steve for the fact that a helicarrier collapsed an entire building on him. Technically, it could be argued that if it weren't for Rumlow, those transports would never have taken off from their docks below the Triskelion, but then again that might just be splitting hairs. Point is, the dude is unhappy and he wants to return the favor for all the pain that was inflicted upon him. As mad as he is, Grillo explained that Rumlow wants to take his time and enjoy his revenge when he finally gets the chance. Sadistic? Very much so.
Though clearly defeated during their last encounter, Crossbones is an enemy who most certainly should not be trifled with. He nearly got the upper hand on Cap during their awesome elevator fight in Winter Soldier, and behind the scenes photos of Civil War seemingly indicate that the Hydra operative has beefed up his arsenal since their last encounter. As Bucky Barnes also clearly represents a weak spot for Cap -- as evidenced in the Civil War trailer -- it would be a fair assessment to believe that Rumlow will use that to his advantage, possibly going after Bucky as a means of psychologically tormenting Cap.
Without getting too far into spoiler territory, it should also be noted by anyone who has ever read Mark Millar's Civil War arc: when Crossbones wants blood, he gets blood.
Captain America: Civil War will release on May 6, 2016, followed by Doctor Strange – November 4, 2016; Guardians of the Galaxy 2 – May 5, 2017; Spider-Man – July 28, 2017; Thor: Ragnarok – November 3, 2017; Black Panther – February 16, 2018; The Avengers: Infinity War Part 1 – May 4, 2018; Ant-Man and the Wasp – July 6, 2018; Captain Marvel – March 8, 2019; The Avengers: Infinity War Part 2 – May 3, 2019; Inhumans – July 12, 2019; and as-yet untitled Marvel movies on May 1, July 10 and November 6, 2020.
Source: The Huffington Post