Purpose. Almost every antagonist has a purpose.
Are they trying the “take over the world” tactic? What got them to this point? Evil isn’t born from the black; it’s molded and crafted by life’s doing. If you’re writing a classic villain – give them the unique back story to give them epic purpose.
If your story is that of the everyday, then where is the bad guy? Are they standing right next to the main character? Are they in the cubicle next door? Are they after the same goal as the protagonist? The opposition is what gives the antagonist in this scenario purpose.
Here’s another one: your character is going against the government, or any large institution, “1984”-style. Why did this entity grow to be the way it is Why is the protagonist going against it? There shouldn’t be a “pure evil” motive because that means there’s someone behind the whole thing. It starts to blend in with other potential antagonist. Don’t confuse yourself! But there’s always…you guessed it…purpose behind the institution.
A new favorite and trend we see in writing is the internal antagonist. This mostly revolves around characteristics of the character and being held back by these traits. For the first time throughout this piece, purpose is stripped from the “antagonist” and comes to fruition out of some event or comes to light. These become more realistic because it may be an accurate portrayal of life itself.
So…take to the books and get writing your perfect, purposeful antagonist. Alright, we’re done using the ‘p’ word.