Conflict creates rising Tension ultimately resulting in Climax and (hopefully) Resolution. With resolution comes Denouement or gradual reduction in tension.
These are all arbitrary guidelines for the beginning writer at best and in my writing, they’ve been thrown out the door a number of times.
But the antagonist can be the beginning and end of story -- one of the most important elements. To ensure this, some writers work very hard to "plot" his or her story in order to create and maintain the kind of rising tension, initiated by a powerful antagonist and required for a really good story.
That writer would spend plenty of time in her initial structuring of the book on that particular element of story with a definitive profile and the full development of the character.
But what happens when your novel takes a side trip from your planned itinerary and you have to go back, pick up and try again? I was not able to control that.
In my novel, “When the Eagle Flies with the Condor,” the antagonist is not a person, but a situation arising out of emotions such as feelings of abandonment, estrangement and perhaps even jealousy.
It is unrequited love. Sound corny? Not when the love is between brother and sister. Their love is more representative of “agape” (from the Greek) than romantic, but the point is, it wasn’t planned that way. It happened and I wanted to be as honest as I knew how to be, thus allowing the antagonist to become whatever it needed to become.
I do believe that having a good idea of what your story is going to say and knowing how it will end is one way to write a novel. But I also agree with some who say that allowing the mind to soar uncontrolled into unexpected regions can be very satisfying and productive and end up perhaps being more. . . well. . . or maybe. . . less -- formulaic? It's my understanding this is called the "panser" method rather than the "plotter" method.
I rather like the term. Perhaps I've been a panser rather than a plotter all along. Or maybe a "plodder." You get the idea.