To get a good definition of what a secondary character is, think about your favorite book.
In my case, that’s really rather difficult to do since I love so many. I mean, how in the world does a girl choose?
Let’s just go eenie meenie miney moe across my shelves and choose The Lightning Thief by Rick Riordan. Considering its popularity a decade ago (or more?), you may very well have read it. But in case you haven’t…
It’s been a bit since I read the book myself, so I will admit to relying on Wikipedia for the following description:
The Lightning Thief is an American fantasy-adventure novel based on Greek mythology, the first young adult novel written by Rick Riordan in the Percy Jackson & the Olympians series…
The novel charts the adventures of modern-day 12-year-old Percy Jackson as he discovers he is a demigod, the son of a mortal woman and the Greek god Poseidon. Percy and his friends Annabeth Chase and Grover Underwood go on a quest to find Zeus’ stolen lightning bolt and prevent a war between the gods Zeus, Poseidon and Hades.
According to that description (and the book itself), Percy Jackson is the main character. And Annabeth Chase, Grover Underwood, Zeus, Poseidon and Hades are secondary characters.
Then again, so are Chiron, a centaur who disguises himself as a human teacher to keep an eye out for Percy; Sally Jackson, Percy’s mom; Gabe Ugliano, Percy’s stepdad; Clarisse, a demigod bully; Thalia, a demigod who’s already dead by the time the story starts; Kronos, the bad-to-the-bone villain of the story…
Depending on the story, the secondary character role call can make for a very long list.
In case you’re still unclear about it, here’s a further definition of a secondary character.
Secondary Character
This is any character that takes a prominent role in the story but doesn’t get to tell it (or at least not the majority of it) from his or her perspective. These figures can and usually will voice their thoughts or show their feelings with actions or expressions. But these are all (or at least mostly) relayed via the main character’s perspective.
A best friend, the villain, a mentor, a parent or any other man, woman, boy, girl, animal or entity that doesn’t take center stage but still leaves a significant indent on the story line can be a secondary character.
These personalities don’t need to be on every page. They don’t even need to be in every chapter. For that matter, you might not even ever actually meet them.
But if they have some obvious influence on the plot, then they’re almost indubitably a secondary character.
After I selected The Lightning Thief as this post’s example, I realized how incredibly perfect it was.
Because, as the segment above notes, you don’t necessarily have to ever meet a personality in order for him, her or it to be a secondary character. Take Thalia, the demigoddess who's already dead by the time the story begins.
She’s now essentially a tree, so to speak. We never ever see anything of her other than that tree, but we still become acquainted with her in other ways. For example, we know that her spirit was so strong that the tree it now resides in acts as a magical force to protect everyone past that point.
That’s a pretty important detail, as the novel makes known early on. So is the fact that Thalia’s death greatly impacted the much more major secondary character, Annabeth, influencing her in how she behaves throughout the novel.
Really, that right there is what separates a main character from a secondary character, and a secondary character from a tertiary character. It’s all about influence.
If the whole story revolves around a personality, then that’s the protagonist. If a significant part of a story is established or pushed along by a personality, then we’re talking about a secondary character.
And a tertiary character? Well, those critters are barely characters at all. More like props. In the character scheme setup, that’s just the way it goes.