Supporting characters aren’t the headliners of your novel, but that doesn’t mean they’re not important. Secondary characters serve a role and affect your protagonists. That means you’ve got to put work into creating them. Even if they only appear in one chapter or have a singular line, you don’t want them to be cardboard. When every person in your book is well-rounded and real seeming, the world you build becomes more engrossing. The best secondary characters are memorable, serve a purpose, and impact the story.
Make Them Memorable
Chances are you know a lot about your main characters. You might have taken the time to sketch out backstories for them—you know about their family, breakups, former jobs, and disappointments. You’ve put time into considering what they look like, how they talk, where they’re from, and how they view the world. The time you put into those efforts are worthwhile—it informs the way these characters speak and how they act in tough situations.
The same effort should go into secondary characters as well. Even though you won’t go into the same level of detail about them, your reader should find them memorable. Do they have a distinctive pattern of speech or dress? Do they antagonize your protagonist, aid them, or make them see information in a new way? What do these characters want? The clearer you are about the purpose the character serves and why you’re casting them in this role—and not someone else—the better they’ll be.
Supporting Characters Should Serve a Purpose
As with every scene description, piece of dialogue, or narration, your secondary characters must serve a purpose. That purpose has to be the plot of your story. You shouldn’t add in a colorful character simply because you enjoy writing them. That character has a job to do in the novel. It needn’t be monumental, but it should be clear. For instance, a friend isn’t only a sounding board. She might reveal a truth the protagonist can’t see. A waiter might report a clue. A mother might remind the hero of his values. If you’re debating whether or not a secondary character has a place in your story, ask what purpose they serve.
Supporting Characters should have an Impact
Your secondary characters have a role to play in your story, which means they’ll have an impact. Secondary characters are just as likely to inhibit as to help your protagonist. An easy handicap for deciding how these figures will affect the story is to think about how they’ll influence the main character. Will they provide a clue? Be a potential love interest? Warn the protagonist about an impending danger? Lead them astray?
In addition to having a job in the book that serves the plot, secondary characters can represent a theme or motif. Nobody wants to read about a hero fighting “evil” because that’s too broad—it has to be personified. Maybe that’s what your character is. Screenwriting advice often talks about the “stakes” character—the sympathetic person that represents what the heroine is fighting for. Supporting characters can represent different sides of a hero’s emotional journey too: the deflector, the feeler, the thinker, the believer, etc. Whoever you write, just be sure they’re there for a reason.
The main way to write great supporting characters is to focus on making them memorable and ensuring they have an impact because they serve a purpose in the book. Happy writing!