Secondary characters are the guests at your story’s party—they’re the ones who keep things interesting. Without them, it’s just your protagonist talking to themselves in an empty room, and nobody wants to read that.

Many writers unintentionally treat side characters like props, as if they’re there just to make the main character look good or move the plot along. But treating them like action figures instead of actual characters can cost you valuable storytelling opportunities—and readers.

Secondary Characters vs. Side Characters

We know—it’s easy to get confused here. What is the difference between secondary characters and side characters? Aren’t there just main characters and everyone else? Yes and no. You can think of side characters as “everyone else,” but secondary characters are side characters with impact. They aren’t simply there to fill out a scene or prop up the main character, but to push your plot and story forward.

Think: John Watson from Sherlock, Miriam Black from The Broken Earth Trilogy, or Samwise Gamgee from The Lord of the Rings.

[Want to know the difference between plot and story? Read here.]

What Are Secondary Characters For?

The short answer: a couple of things. They’re there to flesh out your world, create obstacles, save the day—or do anything else that a character can do in your world. 

  • Making Your World Feel Real. Secondary characters show readers that the universe doesn’t revolve entirely around your protagonist. When executed well, they make your story feel consistent and lived in.
  • Adding Depth to the Story. No two people are the same and no two characters are either. That means you can use your side characters to reveal hidden angles of the main conflict or introduce subplots or key information.
  • Influencing the Main Character. Relationships with the supporting cast bring out different facets of the protagonist—good, bad, or ugly.
  • Highlighting Your Story Themes. Your side characters can reflect or challenge what your story is really about.

Common Mistakes That Kill Your Supporting Cast

Just as there are well-known main character tropes to avoid, keep an eye out for trope-strained side characters:

  • The One-Note Sidekick. These characters exist purely to embody one trait—like the eternally grumpy best friend or the relentlessly optimistic sibling. If they don’t have layers, they won’t feel like real people, and readers won’t care about them.
  • The Convenient Helper. These are characters who pop in only when your protagonist needs a solution or a push forward, then disappear without leaving a trace. It’s a missed opportunity to weave them meaningfully into the fabric of your world.
  • The Walking Stereotype. Leaning on clichés—like the “mean girl” or the “mystical mentor”—makes your story feel uninspired. Readers have seen it all before, and they’ll quickly lose interest if you don’t add something fresh to the mix.
  • The Static Placeholder. These characters are stagnant—they never change, never learn, and never surprise the reader. If they’re not evolving in some way, they’re not contributing much to your story.

Fixing these issues doesn’t mean overcomplicating things. Just remember: every secondary character should have a purpose and a spark of individuality that brings them to life. Treat them with the same care as your protagonist, and your story will feel richer for it.

Bringing It All Together: A Quick Exercise

Grease your writing wheels with a quick and easy exercise on developing secondary characters. Pick one that you like, either from a project you’re already writing or one that you’re planning to work on, then write a mini-profile for them. You don’t need to go into deep detail, just a few stats: 

Name:

What Do They Want: (This doesn’t have to be big—just something personal to them.)

Their Biggest Flaw:

How Do They Interact with the Protagonist: (Are they a helper, challenger, or something else?)

What’s One Lesser-Known Detail About Them: 

A Quirk or Habit They Have:

One Secret They’re Keeping:

 

With a little practice, you may find that your side characters even become your favorites. 

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