5 Cillian Murphy, The Scarecrow (Batman Begins, 2005)
Murphy plays Dr. Jonathan Crane, a corrupt psychiatrist who dons a scarecrow mask and uses a fear-inducing hallucinogen to drive people insane. During his first-ever big screen appearance, the character isn’t even the primary villain, but he’s the most memorable, putting the word “dark” in the Dark Knight.
4 Tom Hiddleston, Loki (Thor, 2011; The Avengers, 2012; Thor: The Dark World, 2013)
Thor’s adopted brother, Loki, aspires in his first appearance to become the new king of Asgard. However, in his second, he seeks to subjugate Earth. Always thwarted in his attempts, he accomplishes something really horrible in The Avengers: he kills Agent Phil Coulson (Clark Gregg). Sure, he’ll later come back to life, but this act still packs an emotional punch.