6. Red Skull (Marvel Cinematic Universe)
Johann Schmidt was one of the best things about Captain America: The First Avenger - which is no mean feat, since it was a decent movie. However, the actual Red Skull aspect of his character wasn't unveiled until quite near the end when he is first confronted by Steve Rogers, at which point he makes an escape before returning in the final scenes for the dramatic climatic battle. He would, of course, seemingly perish in that final battle - dissolving in a great big flash of bright light when he tried to handle the Tesseract - meaning that the time he spent being depicted on-screen as the Red Skull so recognisable from the comics was very short-lived. The redeeming fact about this, however, is that he may have been absorbed in to the Tesseract and thus still exists within it, meaning that a return to the screen in the future (perhaps as part of an MCU Masters of Evil) could still be possible. Although that seems unlikely, given Hugo Weaving's very candid reluctance to return in the role, the fact that there's a slight chance of seeing the character again is somewhat consoling.