How does a villain make a novel successful?

A compelling villain adds depth and tension to a novel, driving the plot forward and challenging the protagonist. Their motivations and complexities can create moral dilemmas that resonate with readers, making the story more engaging. A well-crafted antagonist often reflects the fears and desires of the protagonist, enhancing character development and adding layers to the narrative. Ultimately, a strong villain can elevate the stakes, making the journey of the hero more impactful and memorable.