How Complex Should Side Characters Be?

I used to think that every book needed a few side characters that were flat, i.e. mostly one-dimensional, without a lot of backstory, existing just to bolster certain scenes.

But recently I have read a lot of books with complex, nuanced side characters. Characters that have their own identities and their own stories, even though they aren’t the protagonist. These books have made me rethink my belief that stories benefit from flat characters.

To be clear, this post is talking about side characters. Not the protagonist, not the love interest. The best friend, the side kick, the quest buddy, the girl you sass in the hallway at school. Some authors leave them simply described, embodying just a few key characteristics, while others spend time ensuring that every character in their story has deeper motivations and backstory that explains them. So…which is better?

Comic relief.

Flat characters make wonderful jokes. They are free to exist simply as the Idiot, the Class Clown, the Drama Queen, or whatever other role they fill in the story. They will not win any awards for creativity, but they can help inject some humor into a story without weighing it down with extra details.

A little bit of realism.

We do not know the deep desires and secrets of everyone we interact with, even if they are important in our lives. Sometimes—at least for me—I see a person largely as one characteristic, mainly because they play one distinct role in my life. They are important in that role, but to try to shove an extra subplot into my story surrounding them wouldn’t really make sense.

Sometimes, I don’t care about your backstory.

I think the reason that I initially preferred flat side characters over round ones is that I read a lot of books that weren’t done well. Backstory and subplots can really strengthen a book (more on that later), but when they are done badly, they can make a story feel choppy and overdone. If there isn’t a reason for me to care about the protagonist’s sister’s darkest secret, don’t waste time telling me about it.

They kill stereotypes.

Flat characters often exist only to embody stereotypes. That can add humor to a story (see #1 above), but it can also hold a story back. When authors take the opportunity to flesh out side characters—pushing past their original defining characteristic—their stories stop relying on stereotypes and really come to life.

They are opportunities for more diversity.

I want books with racially and sexually diverse protagonists, but I also want stories with white/cis protagonists to have diverse side characters. But to add in side characters that are diverse on paper but that are never explored in the story does absolutely nothing. In this case, rounder side characters are a must.

More bang for your buck—you get multiple stories in one book.

This one is pretty obvious. Why would you want to read one person’s story when you can read three or four people’s stories? It’s the reason readers enjoy stories with more than one POV, and it is the reason stories with round characters are often more interesting than ones with flat characters.

Complex stories are more captivating them simple stories (often).

Assuming that the story is written well, I like stories that have more than one layer, that talk about more than one thing, that explore lots of different sides of human nature. When side characters are left flat, this is less likely to happen, and I find myself less entranced by stories.

---

Right now, I am siding with round side characters. Who knows what I’ll think in another year.

What do you think? What are your favorite books with flat/round side characters?