What Are Supporting Characters? (Mentors, Best Friends, Love Interests, and More)

Your novel needs a protagonist (main character) … but unless you’re writing something highly unusual and experimental, you’ll have a cast of more than just that one person.

Some of the characters in your story will have walk-on roles: the waiter who brings your protagonist a coffee, the taxi driver who gets your protagonist home, and so on. These are “minor characters” who may not even have names and perhaps just a few words of description.

But other characters will be far more significant. Maybe your protagonist’s best friend is along for the ride, or there’s a love interest or two. Perhaps your protagonist has a mentor figure who guides them at the start of their character arc.

All of these people are supporting characters in your story. We’re going to take a look at how to figure out the cast you need and how to develop your supporting characters (without them taking over the story from your protagonist).

What is a Supporting Character? (Supporting Character Definition)

A supporting character is any character who isn’t the main character … but who still plays a relatively large role in the plot. You’ll sometimes hear them called “side characters” or “secondary characters”. They might undergo some character development or even a full arc of their own … but that’s not essential.

Different types of supporting roles include:

• Best friends or sidekicks. Perhaps you’re writing a story with a protagonist (think Harry in the Harry Potter books) with a couple of close friends (Ron and Hermione). Often, the best friends/sidekicks will be closely involved with the protagonist’s journey.
• Deuteragonists. Your protagonist is your main character – and your deuteragonist is your second most important character, if you have one. Think Han Solo in Star Wars or Robin in the Batman stories.
• Love interests. A love interest could be a huge part of your story, rising to the role of a deuteragonist (e.g. in a romance novel) … or they could be part of a subplot or secondary storyline. Your story could potentially have more than one love interest (like Gale and Peeta in The Hunger Games).
• Foils or enemies. For stories rich in conflict, you ideally want some supporting characters who get in your protagonist’s way. This won’t necessarily be the story’s antagonist: a well-meaning but meddling family member or a friendly but competitive work colleague could act as a foil to your protagonist.
• Mentors. Your story might involve some kind of mentor, teacher, or guide, especially at the start. Think Gandalf in The Hobbit, for instance. Mentor characters will often be wise and experienced, offering guidance and support to your characters … but they may not be directly involved in the action.

Any of the types of supporting characters above could act as comic relief, too. Haymitch in The Hunger Games is a mentor to the protagonist Katniss and the deuteragonist/love interest Peeta, but (at least to begin with) he’s drunk most of the time.

Not all stories need all the types of character above … though most stories will involve some kind of friend or companion for the protagonist. (Even stories where the protagonist starts off alone, like Ryland Grace in Project Hail Mary, will often connect with another character partway through—like Ryland meeting and learning to communicate with the alien Rocky.)

Tip: If you want to take more of a “character archetype” approach to this, Jana Van der Veer has a great post on Set Your Muse on Fire about what character archetypes are and how to use them.

How Many Supporting Characters Should I Have in My Novel?

There’s no rule about how many characters your novel should have, and this will vary by your genre and the length of your book. However … readers may get confused if you throw in too many characters.

I’d suggest that you have:

• (Probably) one protagonist, possibly two in a dual narrative. Even if you don’t see one particular character as your “main” character, your readers probably will.
• Two to four other characters who are really important in the story. You might see this whole group, along with the protagonist, as your “main characters”. These may be point of view characters.
• Perhaps four to ten other supporting characters—ones who appear several times in the book, have names, and have some impact on the plot.
• Other minor characters as needed (if they’re only appearing once, it’s easiest not to name them).

Shorter novels will tend to have fewer characters—and short stories might only have 2–3 characters total.

Massive epic novels can have more characters: in The Lord of the Rings, Frodo is the protagonist, but there are eight other major characters who form the Fellowship … and a huge number of other secondary characters who still have a fairly significant role.

Worried your supporting cast might have grown a little too large? Ask a beta reader or writing friend to look over your draft.

How to Develop Great Supporting Characters

I’ve got a handy list of different ways to develop characters … but when it comes to supporting characters, there are a few key mistakes to avoid.

#1: Don’t Write a Character Description and Stop There

Your characters are way more than their physical description. Even supporting characters who play a fairly small role will need a personality and a sense of who they are and what matters to them.

You might think about what their life is like as a whole, for instance: what’s their backstory?

#2: Think Beyond Character Quirks

Some writers love to create characters with interesting quirks … but quirks alone don’t make for a good character.

Let’s say your supporting character is always shuffling a deck of cards. Why? Is it a coping mechanism? A signal of deeper personality traits? Will it serve a role in the story?

#3: Consider How Your Supporting Characters Fit Your Story as a Whole

Your supporting characters might reflect your story’s themes, directly affect the protagonist’s arc, or move the plot forward—intentionally or not. They should serve a meaningful role, not just fill space.

#4: Give Your Supporting Characters Lives (and Problems) of Their Own

Supporting characters shouldn’t feel like they only exist when the protagonist is around. They have lives, responsibilities, and struggles too.

Maybe your protagonist’s friend has a demanding job. Maybe the mentor is sick or facing their own crisis. These external challenges can enrich your story and add tension.

Supporting characters are essential: they deepen the world, add dynamics, and challenge or support your protagonist in ways that matter.

For more help with characters, check out my roundup of posts that cover developing and writing characters.