Secondary characters play an essential role in any story. Still, they are especially crucial in thrillers because they help create a sense of tension and suspense and support the protagonist.

Supporting characters can be co-workers, best friends, love interests, mentors, relatives, or anyone who helps move the plot forward. This blog post will discuss these secondary characters and what they do in a thriller novel.

The main characters and their purpose in the story

The protagonist is the main character of a thriller story. They are usually determined and driven and will do whatever it takes to find the truth and solve the mystery.

Other equally vital characters in a thriller story include the antagonist or the villain, working against the protagonist.

Five familiar secondary characters and their purpose in the story

Creating secondary characters in a thriller novel is as important as the main characters. They provide support, information, and sometimes comic relief. Without them, the story would be one-dimensional and not nearly as interesting.

1. The co-worker character

The co-worker is usually the first person that the protagonist meets. They are often introduced in the novel’s opening scenes and provide an immediate connection to the story.

Their purpose in the story:

Co-workers can offer help and assistance when needed – whether it’s picking up slack in work or just being a shoulder to lean on during tough times. Co-workers can encourage and motivate the protagonist through words and actions.

They can also be a source of comic relief, always welcome in a thriller. This character is usually the protagonist’s equal in job position and skill. They may be friends or rivals, but they provide a sense of competition.

The boss can be another essential character providing the protagonist with clues or information that they need to solve the mystery. They can also be a source of conflict if they disapprove of the protagonist’s methods.

2. The best friend character

The best friend is someone who knows the protagonist well and can offer advice or support when needed.

Their purpose in the story:

A best friend can be a great source of support for the protagonist of a story. They can provide moral support, practical help, and emotional comfort. Often, a best friend is someone the protagonist can confide in and who will help them through tough times. A best friend will always be there for the protagonist, no matter what happens.

A best friend can act as a sounding board for the protagonist’s thoughts and feelings, which can help the reader understand what is going on in the protagonist’s mind.

And lastly, they can provide comic relief throughout an otherwise tense story.

3. The love interest character

The love interest is someone who may or may not be interested in the protagonist, but it is a secondary character that the protagonist is attracted to.

Their purpose in the story:

A love interest can offer the protagonist emotional and psychological support, manifesting as encouragement, sympathy, comfort, and hope. Ultimately, a love interest validates the protagonist and makes them feel loved and seen, which is incredibly important for a character who may be struggling with self-doubt or feeling isolated.

The love interest can be a help or a hindrance, depending on the story and are often the source of conflict for the protagonist. For example, they might be involved with someone else or not return the protagonist’s feelings. Either way, the love interest is a crucial secondary character who drives the plot forward.

For example:

In The Girl with the Dragon Tattoo, the brilliant and resourceful character Lisbeth Salander uses specific skills to investigate a crime committed against her.

She develops a complicated relationship with Mikael Blomkvist, who hired her to help him with his investigation. This relationship ultimately impacts both Lisbeth’s personal development and the course of the story.

In another example, consider Naomi Watts’s character in The Ring. Naomi plays a mother desperately trying to protect her son from a curse that she believes is responsible for her daughter’s death. Naomi is a secondary character, but she plays a vital role in the story.

4. The mentor character

The mentor is a secondary character who provides the protagonist with guidance and wisdom. They are usually older and more experienced than the protagonist, and they help them see things in a new light.

Their purpose in the story:

Mentors can provide invaluable support to protagonists, both professional and personal development. By sharing their wisdom, knowledge and experience, mentors can help protagonists reach their potential and achieve their goals. In addition to offering advice and guidance, mentors can offer specific skills training or help with task-related issues.

There are many examples of protagonists benefitting from a mentor relationship in thrillers. For instance, in Gillian Flynn’s Gone Girl, Nick’s father encourages him to stand by his wife no matter what (even though they found out that she was a notoriously manipulative individual). Similarly, in Dan Brown’s Inferno, Sienna Brooks provides critical help to Robert Langdon as he tries to prevent a global pandemic.

While the mentor is often a positive force in the protagonist’s life, there are also examples of this relationship gone wrong. For instance, in Patricia Highsmith’s The Talented Mr. Ripley, Tom Ripley murders his wealthy friend and benefactor after growing tired of living in his shadow.

5. The relative character

A relative can add an extra layer of suspense and mystery to a thriller story, as the protagonist keeps the information from them secret while also trying to protect them.

Their purpose in the story:

A few different things can happen when you introduce a relative into a thriller story. For one, the relative can provide vital information to help the protagonist solve the mystery or save the day. Alternatively, the relative can be kidnapped or killed, which throws the protagonist into further turmoil and creates more suspense and excitement.

For example:

A young female protagonist can be especially vulnerable if her relative is threatening or dangerous. For example, in the film The Girl with the Dragon Tattoo, Lisbeth Salander’s guardian is a violent man who sexually assaults her regularly. Lisbeth must find ways to protect herself from him while also trying to uncover his secrets.

But in the novel Gone Girl, the protagonist’s sister provides a key piece of evidence that helps him solve the murder mystery.

The presence or absence of a relative can significantly impact how the story unfolds.

Tips for creating rich, believable secondary characters

– Make sure your secondary characters serve a purpose in the story. There’s nothing worse than a character who feels like they’re there to fill up space.

– Give your secondary characters their distinct personalities and voices. It’s easy for supporting characters to blend in memory if they all sound alike, so put some effort into making each one unique.

– Consider your character’s weaknesses, including flaws and imperfections, and how the people around them might exploit them. Do they tend to trust too easily? Is there something they are embarrassed or ashamed of that others could use against them?

Understanding your characters’ vulnerabilities will help you create conflict and tension in their interactions with other characters. No one is perfect, and that includes fictional characters! Your readers will be more engaged with the story by making them relatable.

Examples of well-done secondary characters from popular thriller novels

There are so many great examples of well-done secondary characters thrillers that it’s hard to pick just a few, but here they are:

The Girl on the Train by Paula Hawkins features several solid and well-developed female characters, chief among them the protagonist Rachel. While Rachel is undoubtedly the star of the show, the other women in her life are fleshed out with impressive depth in their significant roles.

Gone Girl by Gillian Flynn also has a killer cast of supporting female characters surrounding the two leads. Every woman in this novel is complete and complex, making for a genuinely captivating reading experience.

The Silence of the Lambs by Thomas Harris is another excellent example of a book with well-rounded secondary characters. Both Starling and Lecter are fascinating, but the people in their orbit bring the story to life.


Secondary characters can make or break a thriller novel. They need to be believable and richly drawn for the reader to suspend disbelief and become immersed in the story. If you’re having trouble creating believable supporting characters, consider using real people as inspiration, and give them well-defined goals and motivations.

With careful attention to detail, your secondary characters will come to life on the page and help transport your readers into a thrilling world of suspense.

If you’re working on your first novel and are looking for more help with your writing, please check out our other articles at

Best of luck with your writing!


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