Remember, the fundamental principle of character arc is Lie vs. Truth.
In any type of positive story (i.e., Positive Change or Flat Arc—in contrast to Negative Change Arcs), the Lie will be dominant in the beginning, only to slowly and inexorably be overcome by the Truth. In a Positive-Change Arc, the protagonist himself will start out believing that Lie until he is taught by the events of the story to embrace the Truth.
Flat Arcs, however, are different. In a Flat Arc, the character starts out already in possession of the Truth—and then uses that Truth to bring positive change to the world around him.
As such, the Flat-Arc protagonist is a person who, on the specific level of the Truth, has things figured out. He’s the most with-it person in the story—and in danger of becoming one-dimensional and obnoxiously goody-goody.
The challenge of the Flat Arc is to tell a story about a protagonist who understands and claims a Truth, but who is still flawed, fluid, and interesting. The Flat-Arc character, unlike the Positive-Change Arc character, does not believe a damaging Lie. But he does have a Doubt.
How “the Doubt” Keeps Flat Character Arcs Vibrant and Relatable
Just because your Flat-Arc protagonist understands the story’s fundamental Truth doesn’t mean she will be 100% sure of that Truth or her own ability to live it. This fluidity in recognizing her own fallibility is what makes Flat-Arc protagonists endlessly compelling.
Like us, they believe in something. But also like us, they recognize they could be wrong. They could have been blinded by another Lie. They could have chosen the wrong Truth. And even if they did choose the right Truth, then maybe they won’t have the wisdom, strength, or conviction to live it.
In short, they have a Doubt—and it keeps them seeking throughout the story, even as the undeniable power of their conviction in the Truth transforms other characters around them.
For example, Wonder Woman‘s Diana Prince is a solid Flat-Arc character. From the beginning, she understands and embraces the Truth that “only love will truly save the world.” She uses that Truth to change the lives of soldier Steve Trevor and, ultimately, to end World War I.
And she’s pretty unshakable in that Truth—to the point that her blind faith allows for some of the story’s more humorous moments.
But if that’s all Diana Prince was, she would have been a dreadful character: one-dimensional good-goody at best, psychotically single-focused at worst.
That’s where Doubt comes in. For most of the story, Diana does not doubt her Truth, but does doubt her own ability to carry it out. And in the Third Act, when faced with the true enormity of the Lie, she is also given cause to doubt the Truth itself and waver in her devotion to it before reclaiming it and acting on it with even greater conviction in destroying Ares.
(Note, however, that her moment of Doubt after the Third Plot Point could have been better developed had that same Doubt been set up in the First Act, in addition to her Doubt about her own unworthiness. Because the story’s most important Doubt was not introduced until late the story, her comparatively brief moment of despair wasn’t undergirded or developed strongly enough to be as powerful as it might have been.)
How to Discover the Right Doubt for Your Flat Character Arcs
You must choose a thematically-pertinent Doubt for your Flat-Arc protagonist. Diana’s arc could have been stronger had it introduced earlier the Doubt that was most pertinent to her final confrontation with the Lie. Although your character can harbor multiple Doubts, the primary one should be directly related to the Truth: Is it really the Truth? Is it really worth fighting for?
Your character’s Doubt can range from being a niggling question to a full-on existential crisis. However, remember this is a Flat Arc. The character will not fundamentally change. He will believe the Truth in the beginning, and he will reaffirm that belief even more strongly in the end.
His possession of the Truth must be strong enough throughout the story to effectively impact the supporting characters and inspire them to recognize and reject the Lie. The protagonist’s Doubt can occasionally get in the supporting characters’ way, but it cannot become an insuperable obstacle.
Flat-Arc characters can be tricky to execute well, since they are often perceived as static. However, nothing could be father from the truth. Handled skillfully, Flat-Arc characters are amazingly vibrant and powerful personalities, not least because they are able to confront and conquer their own demons right alongside those the Lie has inflicted on the world around them.