How the ancient Enneagram System can help writers build richer, more believable characters
Writers spend enormous energy on backstory, motivation, and physical description. But personality is often the missing piece. Using Enneagram personality types for character development gives writers a proven framework to build characters that feel real, stay consistent, and drive compelling stories.
What is the Enneagram?
The Enneagram is an ancient personality-typing system with nine core types. Its exact origin remains unclear, but it has existed for hundreds of years. Psychologists and religious leaders originally used it to better understand human behavior. Today, it has experienced a strong resurgence in pop psychology — and it turns out, it works beautifully for fiction.
How one author discovered it
Author Greta Boris, who writes psychological suspense, discovered the Enneagram early in her career. She needed a fresh protagonist for each book in her Seven Deadly Sins series. Each character had to feel distinct and believable. The Enneagram gave her a reliable starting point, matching personality types to the specific sins her characters embodied.
Each Enneagram type comes with strengths, weaknesses, core fears, and deep motivations. Writers can use this profile to ensure their character would realistically make the choices a plot demands. Without that grounding, characters can feel forced or inconsistent, and readers notice.
The health spectrum
One of the most powerful features of the system is the health spectrum. Every personality type can exist at varying levels of emotional health. A character at a healthy level behaves very differently from the same type in a stressed or degraded state. This spectrum makes it possible to build nuanced, believable character arcs in either direction.
Characters don’t change their core Enneagram type. What changes is their health level within that type. A character who grows over the course of a novel becomes a healthier version of themselves. One who spirals becomes a more destructive version. This distinction keeps arcs grounded and avoids the pitfall of characters who change too dramatically to feel real.
Writing villains with the Enneagram
The health spectrum also helps writers craft compelling villains. Some personality types, when they deteriorate, turn inward and become self-destructive. Others externalize their breakdown and grow dangerous. If you’re writing a character who commits violence, you need a type capable of that external collapse. The Enneagram tells you exactly which types fit.
Pairing a protagonist and villain with the same personality type — but at opposite ends of the health spectrum — creates especially powerful tension. Readers sense the connection without always being able to name it. The contrast makes both characters more vivid and the stakes feel more personal.
Wings and complexity
Wings add another layer of complexity. Each Enneagram type is influenced by one of its two neighboring types on the nine-point diagram. Two people can share a core type but behave quite differently depending on their wing. For writers, this means you can create varied characters without straying from the system.
Personality shapes genre
The Enneagram also influences genre. Boris uses a clever exercise with Cinderella as an example. Change Cinderella’s personality type, and the entire story shifts. A justice-driven, anger-fueled Cinderella might overthrow her stepmother with force, and suddenly, it’s a thriller. A joy-seeking, spontaneous Cinderella becomes a rom-com. Personality shapes genre more than most writers realize.
For romance writers, the system is especially rich. You can explore which types are naturally attracted to each other, which types clash, and what those conflicts look like in daily life. If you feel like your characters always end up in the same jobs or the same relationship dynamics, the Enneagram can break that pattern fast.
When to use it
Writers sometimes worry they need to type every character before they start. In reality, you can use the system at any stage. Boris recommends focusing on protagonists, love interests, mentors, and villains. For a series with a recurring cast, typing secondary characters helps maintain consistency across books.
Discovering the wrong type mid-draft is also common — and fixable. Boris herself realized mid-book that a villain she’d written didn’t match his intended type. His behavior was too obsessive and rigid. Recognizing the mismatch let her revise with clarity instead of frustration. The Enneagram gave her a diagnostic tool, not just a planning tool.
Mental illness and personality
Mental illness fits naturally within the Enneagram framework too. Each personality type fractures differently under extreme stress. You don’t layer mental illness onto a character separately. Instead, you follow how that specific type breaks down, and write the realistic, painful result of that collapse.
Where to start
The best place to start is to type yourself. The Enneagram Institute offers free resources and clear descriptions of all nine types. Many sites also list famous figures associated with each type, which can spark ideas quickly. Once you understand your own type, typing fictional characters becomes intuitive.
The Enneagram won’t write your book for you. But it will stop you from writing a passive, people-pleasing character who somehow blows up the world in Act Three. It keeps your characters human, your plots believable, and your arcs emotionally satisfying — from the first draft all the way through to the final page.
About the author
Greta Boris is a USA Today bestselling author of The Seven Deadly Sins, a psychological suspense series set in Orange County, California. She is also the co-author of Publish: Take Charge of Your Writing Career. Greta has spent years helping writers develop stronger stories through her workshops and courses on character development and the Enneagram.
Editor’s Note: This blog article was written from a previous First Draft Conversation between Alessandra Torre and Greta Boris.
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