5. Scarecrow (Batman Begins)
It makes very little sense to me that the villain who appears in every one of Nolan's Batfilms is the most underused, when, in actuality, he's probably the most interesting. Portrayed by Cillian Murphy, we're given a glimpse into the mad man running the madhouse. I think that's what's so interesting about Crane to begin with; we have no idea how long he's been doing this or to what extent his "experiments" go to. We know next to nothing about the man aside from the fact that he invented a fear toxin, put it in an aerosol spray, and works for the League of Shadows. In so many ways is the
Dark Knight trilogy about fear just as much as it is identity and hope, so why abandon the character who personifies fear (aside from Batman) to cameos in the films following
Batman Begins? When you think of the Batman villains, the obvious three come to mind (Ra's, Joker, and Bane), but the one with the closest MO to Batman himself, and debatably the one who's done the most damage to Gotham citizens over time (overlooking Bane's siege of the city) is often overlooked.
"Would you like to see my mask? I use it in my experiments. Probably not very frightening to a guy like you, but these crazies, they can't stand it."