Antagonist
The antagonist is whoever or whatever stands in the protagonist’s way. Often that’s a person, but it can be a system, nature, or the protagonist themselves.
Antagonist and villain aren’t the same thing. A villain is bad. An antagonist just gets in the way. A loving parent who blocks their child’s dream, a decent detective chasing a likeable thief, an organisation following its own rules: all antagonists, and none of them villains.
It doesn’t have to be a person at all. The classic types of conflict are person against person, society, nature, self or fate. So the antagonist can be a storm, a bureaucracy, an illness, or a character’s own belief that they don’t deserve good things.
The best antagonists want something you can understand. If their goals make sense and their reasoning holds up, the protagonist’s win actually costs something. If they’re just evil, the book usually has to keep raising the stakes to stay tense, because nothing else is creating the pressure.
Antagonist: common questions
Is an antagonist always a villain?
No. An antagonist is anyone opposing the protagonist. A villain is someone morally bad. A sympathetic, completely reasonable character can be the antagonist.
Can the protagonist be their own antagonist?
Yes, and it’s common in literary and character-driven fiction, where the main obstacle is the character’s own fear, pride or self-deception.