So many people can't tell the difference between a villain and an antagonist. Easy mistake. Just remember all villains are antagonists but not all antagonists are villains. Antagonists are characterized by simple opposition. They aren't necessarily evil, they merely have opposing actions, thoughts, motives, etc. to (in a story) the protagonist and easily be one of the heroes or part of the five man band. Whereas the villain is the person who tends to have a negative effect on other characters, normally through doing something cruel and unusual, can they can range from misunderstood or straight pure evil.
Now this can only apply to a few things, namely anime and comic books that have a new villain every other week.But it can apply almost anything. With video game logic, they're normally side bosses or mini bosses. Maybe even the lackeys. In cartoons, it depends on the genre. Now let's apply this to a few things.
Starting with Avatar The Last Airbender, Zuko started out at villain status, but was later down graded to antagonist in Book: Earth through half of Book: Fire before finishing up his little redemption arc. Why is he considered an antagonist? Well in "Earth" we're introduced to Azula who is slightly more powerful than Zuko and then a little later Fire Lord Ozai himself.
In Naruto and by extension Naruto Shippuden, there was more so an antagonist of the arc that was later extended to an antagonist that was really the villain but later plot twists happened. Gaara was an antagonist while Orochimaru was the villain before being downgraded to antagonist for Shippuden....I'm seeing a trend is anyone else seeing a trend?
Let's look at Disney. Nowadays there isn't a lot of people I would call villains. Just antagonist. Hans? A horrible person. Ta fiti (...think that's misspelled) was pissed that her stuff was stolen. A true villain....I'd say Frollo because he was willing to kill a baby after killing a woman on the steps of a church...and he's rapey, don't care if that's not a word, he's creepy as hell.
Now please remember this when you're writing. Now when you have a line up of villains, the antagonist can be one's self or other people. Like in Captain Planet, Ma-ti is the youngest and the smallest, so the others are often looking out for him. Now he's possibly the strongest out of all them, but we might never know because the guy goes emo every third episode....the 90s were weird. Or you hero/ protagonist might accidentally butt heads with the locals over what to do about a sickness. Medicine is an obvious answer, but the locals may believe modern medicine is witchcraft as declared by the local religion. The religious head is the villain in this situation and the locals are the antagonists. Just remember an antagonist can be a who or what and the villain is always a who.