An antagonist is a character, group, force, or idea that opposes the interests of the protagonist in a story. They are the source of conflict in a story and create tension, action, and consequence. The conflict between the protagonist and antagonist is an age-old storytelling trope. The antagonist can be a person, animal, environment, idea, or something flawed within the protagonist themselves. The antagonist is not necessarily evil, villainous, criminal, or deceptive, but can be well-intentioned. The function of an antagonist in a story is to complicate the struggle of the protagonist and create obstacles for them to overcome. Knowing who the antagonist is and what motivates them can greatly improve storytelling.