Who is the antagonist in The Crucible by Arthur Miller?

The primary antagonist in The Crucible by Arthur Miller is Abigail Williams. She is the young servant of Reverend Samuel Parris and the niece of his wife. Abigail leads the group of young girls in the play who accuse innocent people of witchcraft, and she is motivated by her desire for revenge against John Proctor, a farmer and former town official who had an affair with her.