Main antagonists are characters in a story who oppose the protagonist, creating conflict and driving the plot forward. They often embody traits or motivations that challenge the hero, making them essential for the narrative. Examples of main antagonists include Voldemort from the Harry Potter series and Darth Vader from Star Wars. These characters can take various forms, such as villains, rival heroes, or even societal forces. Their actions and decisions often reveal deeper themes within the story, such as morality, power, and redemption. Understanding main antagonists helps readers grasp the complexities of the narrative and the struggles faced by the protagonist.