We all know that in most successful, engaging books—whether they’re mysteries or mainstream novels, you have a group of interesting characters, aside from the protagonist.
In every book, there’s the MC (MC), and then you have the A List. These are characters who participate both in the emotional arc of the main character and the plot arc. The B List participate largely in the plot arc. They can provide information or do things to move the plot along. For example, a B lister might be the medical examiner at the morgue who explains how the victim died by poisoning. Then there are the unnamed characters, the taxi driver who ferries your MC from one place to another. For the next few minutes, I’ll be talking about the A list or secondary characters.
You may have five people who want someone dead, but unless you’re writing a redo of The Mystery on the Orient Express, where 11 people work together to kill the victim, only one person does it. The rest of the suspects are red herrings. But in order to be compelling red herrings, they need to have some heft to them.
suspects often have a secret,
something they desire,
and/or a problematic story they're telling themselves
(for example, that someone is standing in the way of his/her happiness, and that person would be better off dead).
A main character such as Lady Elizabeth in A Lady in the Smoke (discussed elsewhere on this blog) has heaps of backstory including several secrets and desires and problematic stories. But she’s the main character. With secondaries you can get away with less. But I always make sure to have at least two out of the three.
Let’s say you have a dead body—a wealthy, sour-tempered viscount. We have five suspects and each suspect needs his or her own small story that leads to motive.
For example, Professor Plum, who grew up poor, resents the viscount for being rich. Also, the professor has only has ever been drunk once in his whole life, but unfortunately it was at a cocktail party at the Viscount’s house … and the Viscount told the head of the university, which led to the professor being fired from his post, which wasn’t fair, and he wants revenge.
The young niece Miss Scarlet is secretly in love with the Viscount’s wife, who has begun to reciprocate her feelings. Miss Scarlet assumes with the Viscount out of the way, their romance might have a chance.
The greedy cousin Colonel Mustard has gambling debts and he desperately wants the inheritance to pay them off … as well as to pay for the mistress he’s secretly keeping in Grosvenor Square, who is now pregnant and needs financial support.
You have to keep in mind, a villain is never a villain in his own head. The story he has going about why he deserves the money and why the viscount has what’s coming to him is legit to him or her.
But even if a secondary character is Elizabeth’s friend or love interest, he or she has a secret or a desire or something they assume to be true that does not necessarily align with Elizabeth’s character arc or her plot arc.
I’ve removed the arrows pointing toward Elizabeth to emphasize that these characters are standing on their own two feet.
For me, I know my secondary characters are where they need to be when I can put them in a room with my main character, and they move and act and talk to each other. It appears in my mind like a movie, and I just watch and write it down. These secondary characters are standing on their own two feet, and the mystery is richer for them.