The cause of all the story's bad events which the hero(es) must resolve. The arch-villain. The cause of all bad happenings in a story. A Big Bad could be a character with Evil Plans or it could be an omnipresent situation, such as a comet heading towards the Earth. In a serial story, the Big Bad exerts an effect across a number of episodes, even an entire season. Known as the Shadow in The Hero's Journey. This trope is not a catch-all term for the biggest, ugliest villain of any given story.