Stephen King had the same problem in 11/22/63 that I have in Line of Ascent. No bad guy.
Oh sure, in King’s book there are bad guys and problems that pop up, but there is no overarching villain to be defeated except TIME itself. King solves this problem by saying that TIME does not want to be changed. So whenever the protagonist is about to do something significant, random events rear up to stop him, i.e., his car breaks down. He begins to anticipate that this will happen and a fun tension in the book is what will TIME do to protect itself? I love the tagline: When You Fight the Past, the Past Fights Back.
I also have no bad guy. In Line of Ascent, there is the Spanish Inquisition and sinister Cardinal Carafe and a host of natural and human impediments to the quest. But they do not, like Javert in Les Miserables, give us an enemy that carries through the entire story.
Ever since I took Dr. Gary Guinn’s plot workshop, I’ve worried about my lack of antagonist. Last week, when someone suggested that I have my main character return through time to confront his other self, etc., I was horrified. That’s been done, and that is NOT the book I want to write in Line of Ascent.
However, I did realize that this person had put his finger on the issue. No bad guy. In my novel, History itself is the antagonist. But that is vague and nebulous. TIME only became a character in 9/11/62 when King gave it the motive to protect itself from being changed.
In my novel, it’s not that History doesn’t want to be changed—it really doesn’t care. The problem is that History is HUGE and dangerous. It has to be changed in many ways, in many countries to effect Jake’s goal of preventing the Protestant Reformation. It wasn’t just about Martin Luther. It was about the sale of indulgences and Henry VIII’s wanting a different wife.
So I have created the metaphor of a giant octopus/monster with tentacles. Jake explains that each of these can be cut off but the creature still survive. Yet, any one of them can drag you to your death. It is Erasmus who identifies the head of the creature and how they might kill it. I am hoping that the reappearance of this metaphor as the quest progresses will give a certain spine (irony) to it and prevent it from being just a series of episodes.
If you don’t have an antagonist, don’t do as I did and just wonder vaguely if it matters. It probably does—especially for commercial fiction. Try to find a creative way, as King did, to personify the thing that is working against your character. Or if the overarching enemy is some vague idea, like time or history or philosophy, perhaps a metaphor can convey the complexity of the force that stands against your protagonist.