8) Kaecilius
Perhaps the worst instance of a terrific actor being misused by a movie in recent memory would have to be Mads Mikkelsen in Doctor Strange.
To call his character of Kaecilius, who was never that memorable to begin with in the comics outside of being a lackey for Baron Mordo, anything resembling substantial would be an insult to the word. After an admittedly cool beginning, he’s infrequently seen throughout the movie, serving one purpose and one purpose only: to bring his master Dormammu to Earth.
He has no clear motivations outside of thinking that the Ancient One’s ways of restricting magic are wrong, and is never a serious threat against the beginning sorcerer Strange. That he ends up getting killed by Dormammu at the end was beyond pathetic. In what was otherwise a terrific film, Kaecilius sticks out like a sore thumb.