5. Crossbones & Sin
While not a story as such, there’s no doubt that Sin and Crossbones could quite easily carry a movie by themselves as the lead villains for Captain America to face off against. The latter will actually be introduced as a duplicitous S.H.I.E.L.D. agent in Captain America: The Winter Soldier (played by Frank Grillo), so a larger role in the Marvel Cinematic Universe moving forwards just seems like common sense.
In the comics, Crossbones tracks down Sin – the biological daughter of the Red Skull – and the murderous duo then go on to a rampage which brings them to blows with Steve Rogers. They also make it their goal to do all they can to help Sin’s evil father achieve his goals, so these are undoubtedly two villains deserving of the big screen treatment.
