Although Martin Freeman's character has seemingly been revealed as Everett Ross, U.N. liaison to Wakanda, it could still all be a smokescreen for the planned return of Cap's greatest enemy - Red Skull. Now, it's par for the course that any time a new actor/character is added to a Captain America film that fan speculation turns to the maroon-headed Nazi in some new guise. While it's doubtful that Ross is anyone other than Everett Ross - most likely with a view to making him the MCU's new Agent Coulson-type - there does still exist a minor possibility, no matter how small. After all, fans have been clamouring for a Red Skull return for years now - why not now? Heck, it doesn't have to be Ross. If the Russos and their writing team want a secret villain orchestrating everything from behind-the-scenes (aside from whatever Baron Zemo's up to), so as to make sure Cap and Iron Man aren't seen as straight-up aggressors, this'd be the way to go about it.