Movies put a lot of emphasis on the protagonist, but they're hardly the only people on the screen. Films of all kinds have plenty of people who fill the screen, but those are most often background characters who never impact the plot. Of course, that's not always the case, and in some movies, a background character turns out to be absolutely vital to the story. These typically pop up at key moments in the story and often as plot twists.
It's less common than you might think, so when a movie puts the emphasis on a seemingly unimportant character at a crucial moment, it tends to stand out. When it's done well, it can benefit the film's success, and there aren't many movies that qualify. This list highlights the most important background characters the audience assumed weren't important but proved otherwise. Take a look down below, and don't forget to upvote your favorites before you go!