One of the biggest mistakes you can make as a writer is to allow all your protagonists to get along with each other.

Many of us are inclined to do this because we love our characters. The protagonists are all working together toward the same goal, right? So why shouldn’t they have a harmonious relationship?

But this habit keeps writing from being great—and kills the story.

Last summer, I read a Christian fantasy work which bored me to tears for a simple reason: the four or five protagonists always got along and never had any conflicts that weren’t immediately resolved with an apology.

This may be good Christian living, but it isn’t good writing. Nor is it realistic. People naturally fight and distrust each other. It takes a while to become friends with someone else. And even if you’re close friends with someone, that doesn’t mean you’ll never squabble with them.

Which story would you find more compelling? A story where six characters band together to save the world from annihilation and work together perfectly to win the fight? Or a story where six characters all end up disliking each other, feud with each other, and nearly rip themselves apart, but then pull together in the final act to save the world?

I hope you chose the latter, because that’s essentially the plot of The Avengers.

Successful books are ones that create tension and conflict on several different fronts. Conflict between the hero and villain is not enough. There also needs to be strife between protagonists that they must overcome in order to succeed.

Here are four ways you can increase tension between your protagonists to enhance the suspense and quality of your story.

1. Choose Your Protagonists Wisely

There’s a classic writing prompt that challenges you to take two characters who loathe each other and imprison them in a broken elevator for twelve hours. This easily spawns entertaining stories because you’ll have instant conflict no matter what you do. And, as we all know, conflict is a crucial aspect of an interesting story.

When you choose your protagonists, don’t automatically choose characters who will mesh well. Choose characters who will despise each other—or at least won’t trust each other. Then orchestrate the circumstances so that they’re forced to work together.

This is one of the major premises of Thor: The Dark World. Thor asks Loki for help because he has no other recourse. Whatever problems this movie has, this narrative choice isn’t one of them. We not only wonder if Thor will be able to defeat Malekith, but also whether Loki will be loyal or traitorous to Thor. The stakes and suspense are upped, intensifying the story. A similar scenario appears in Lord of the Rings, where Frodo and Sam are forced to team up with Gollum to destroy the Ring.

For those of us who have already written our story, this can be a painful choice if the protagonists are great friends. Two years ago, when I was working on my novel, A Darkened Light, I had the option to send my protagonist with his best friend or his nemesis to defeat the evil overlord figure. In the original version, I sent him with his best friend. But, in retrospect, the more I look at the story, the more I realize that it would have been better if I had forced him to go with his nemesis. That would certainly have been a difficult rewrite considering how much I liked him and his best friend. But we need to be willing to make these sacrifices as authors to create a captivating story.

2. Give Your Protagonists Secrets

Perhaps you don’t want your protagonists to immediately clash, but you still want tension between them and potential for future discord. To accomplish that, give them secrets that they harbor from each other.

The exact form of the secret can vary, but it must be something that the other person can’t know. Plant hints of it early on, and then slowly turn the screw so that the secret becomes even more devastating when it is finally revealed.

“But wait,” you protest, “does the secret need to be revealed? What if the character is able to hide it so that it never becomes an issue?” That way you get all the benefits of increased tension without the hassle of reconciling the protagonists after the secret is blown.

But you’ll also cheat your reader.

Writing is built on a specific set of promises you make to the reader. When you set up a secret between two characters, the reader is intrigued by it because there’s an implicit promise that the secret will invoke future conflict. If you avoid that conflict, although the reader may be temporarily relieved, he’s ultimately going to be disappointed.

This happened to me with a book I read several years ago. I mostly enjoyed the book and it’s still one of my favorites. But a large portion of the book revolved around a subplot between a male character and a seductress that he stays with for far too long. The main character resists the seductress, but he doesn’t flee from her either. The tension heightens. What will happen when his wife finds out? What will she assume about them, and how will he recover?

All the questions were in vain because the main character decides to leave the seductress without any further trouble. Although that was the right decision for the protagonist to make, I felt cheated out of potential conflict. And the main character got away with his foolish choices without any consequences. The book would have been better if the wife had found out and the issue created a gulf between her and her husband. Then the husband would have had another challenge to overcome and the story would have been more compelling.

3. Give Your Protagonists Something to Disagree About

Introduce a new problem, question, or challenge into the protagonists’ journey. Maybe it’s an opportunity for a side quest, a moral dilemma, or a strategy for how to conquer the villain. Then set the characters on opposite sides of the matter.

However, don’t let the characters have one long debate about their differences of opinion and then end up agreeing with each other. If you introduce this conflict, you need to deepen and expand it until a rift is driven between the characters. Will they be able to put the dispute aside and work together? The further you get into the book, the less confident the reader should feel about the answer to this question.

This sort of value/policy conflict is one of the details that makes The Dark Knight Rises such an impressive movie. Alfred and Batman disagree about whether Batman is strong enough to beat Bane, and Alfred doesn’t want to bury another member of the Wayne family. So the conflict escalates, neither of them resolve it, and Alfred decides to leave. The repercussions of this are evident throughout the movie. This isn’t a perfect example because the characters don’t reunite before the climax, but it does demonstrate how powerful this technique can be.

4. Make the Story a Zero-Sum End Game

A zero-sum end game is an economic term for a situation where one person’s success equals another person’s failure; in other words, both characters can’t succeed.

Maybe both protagonists are pursuing the same love interest. Maybe both want to be the hero and get the bragging rights for killing the villain. Maybe the villain puts them in a situation where only one of them can escape unscathed.

Either way, this is a simple but effective method to wreak conflict between multiple protagonists. One central part of the tension between Peter Parker and Harry Osborne in the original Sam Raimi Spiderman trilogy is their mutual love interest in Mary Jane. The screenwriters do an excellent job of tightening the strings on this and other issues until their conflict severely threatens their relationship.

Conclusion: It’s How Jesus Did It

Sometimes, as Christian writers, we believe we must depict characters who never quarrel in order to show the world how beautiful Christian unity can be. But that isn’t how Jesus exhibited the power of the Church to the world.

During Jesus’ time on earth, he could have chosen twelve men who all came from similar backgrounds and easily got along with each other. Instead, he picked fishermen, religious zealots, tax collectors, and political rebels (just imagine how the political rebels got along with the tax collectors). As the Gospels clearly record, all these men also had egos.

The true beauty of Christian unity isn’t shown in people who naturally get along with each other. It’s shown in people who don’t get along but who learn to work together. The Gospel story begins with twelve men who constantly bicker, but it culminates in Acts, with twelve men who are bonded together, faithfully presenting the Gospel to the world.

We can only display the power of unity and fellowship once we’ve first demonstrated how easy it is to fall into disunity and chaos. So make your protagonists hate each other. Seed distrust and tension between them so that they can’t avoid getting embroiled in fights. And then show how they will still be able to work together in the end. It’s how the great writers do characters. And more importantly, it’s how the Great Writer does it.