Literary antagonists are characters who oppose the protagonist, creating conflict and driving the narrative forward. They can take many forms, from villains like Iago in Othello to more complex figures like Jay Gatsby in The Great Gatsby, who embodies both antagonistic and sympathetic traits. These characters are essential for storytelling, as they challenge the protagonist's goals and beliefs, often leading to growth and transformation. The presence of an antagonist can heighten tension and engage readers, making the resolution of the conflict all the more satisfying.