Who is the antagonist?

Well, I could say Rebecca, even in her absence is the novel's antagonist, but I'll go with Mrs. Danvers. Mrs. Danvers was obsessed with Rebecca and doesn't take well to her replacement. She continuously undermines the narrator and causes her to feel inferior, convinces her to dress like the "dead" first wife, and even encourages her to jump out a window. In the end, she even sets the family home on fire.