Captain America: Civil War will feature Robert Downey Jr. as Iron Man. The central conflict will be around Captain and Iron Man, which will kick off the Civil War arc (hence the name) however it seems that there will still be a main antagonist. Marvel has revealed that will come in the form of Daniel Bruhl. Marvel has NOT revealed exactly what role he will be playing at the moment.
Now, I think its safe to say that the main reason over the hype around the third installment of Captain America is to see both Steve and Tony bump heads but how much ‘bumping’ will they be doing with a main villain (especially considering the amount of screen time given to a villain capable of challenging both Captain America and Iron Man) in the film. Perhaps this film will simply serve to establish such conflict between the heroes and see it resolved in later films.
What role can you see Daniel Bruhl portraying?
UPDATE: Its being rumored that Daniel Bruhl will be appearing in Dr. Strange as well if true, this could be a much higher caliber of a villain