Believable characters are one of the most vital aspects of a great book. Failing at this, even momentarily, immediately breaks the suspension of disbelief that the reader has, taking away from the enjoyment of the book to shout (sometimes out loud) “Why would they do that?”

There are three main aspects to believable characters that I adhere to. These are consistent voice, consistent abilities, and consistent reactions. Overall, the theme is, of course, consistency. If a character is going to change and become something else, there must be a story explanation for it – and this is where we get into character arcs. That can be its own blog. Otherwise, characters should change little, if at all, if nothing drives it (pro tip: Put stuff in your story that changes your characters).

A consistent voice for a character means that they have certain word choices or phrasing that is unique to them, and they leverage it throughout the story. In Beginning of Arrogance, Kraven is an orc warrior, and uses the phrase “Intense!” to describe Krell, our protagonist. No other character does this, unless they are intentionally mimicking Kraven. This holds true for all the characters in the book, but it isn’t just word choice. It applies to cadence and precision as well. Another character, Maximus, never uses contractions and speaks in what would be read as a clipped and precise tone of voice. These separations help the reader tell the characters apart, and having them remain consistent throughout the book helps the reader immerse themselves into the story more. It also helps readers to know who is talking when, even if not specified directly.

This voice also applies to the character-to-character interactions as well. The dynamic that the various combinations have, and the language they use toward one another, shouldn’t change without a reason. And in a book, everything happens for a reason.

Consistent abilities are those talents, skills, spells, or other aspect they have previously demonstrated. Examples of failure at this are unfortunately EVERYWHERE in media. The 2007 Transformers movie is filled with inconsistencies, such as when Frenzy can use the AllSpark to recreate his body from nothing, while Bumblebee cannot use it to fix his voicebox.

Essentially, if your characters demonstrate a skill, and then later find themselves in a problem where that skill is relevant, they should use that skill. I find it infuriating when reading to come to a dilemma in the book and all I can think about is “Why doesn’t he cast the same spell to open the door he used before?” If your character can’t cast that spell, there must be – you guessed it – a reason.

Cedric Diggory, they did you wrong and left you dead deliberately. They have a time turner – we know this. They let a student use it for a whole year!

Side note, this is also why introducing any form of time travel into your story is a terrible idea unless handled extremely carefully. It’s the ultimate problem-solving solution, and the only movies I have seen that handled it well are Primer, Bill and Ted’s Excellent Adventure, and Bender’s Big Score. All the other ones – Time Cop, Back to the Future, Looper, and dozens of others – all fundamentally fail at the premise of how time travel works.

Continuing the point, characters demonstrate powers and abilities, and if they could use them to easily solve a problem, then they should either do so, or the author should rewrite the problem so it cannot be solved using that power.

Finally, consistent reactions. When a character is exposed to a situation – a dangerous animal, a magic spell, a hail of arrows – their reactions should be consistent. Kraven reacts with excitement whenever battle is imminent, while Tristan reacts with fear, often suggesting a more diplomatic solution or outright flight. Keeping these reactions consistent is important for the believability of the character.

I find there is sometimes a fourth element for crafting a believable character, which feels horrible to say… but their physical appearance shouldn’t change. I’ve read that in books, where when I flip back 100 pages, the character had brown hair, and now it is inexplicably red.

How I manage this is to create a character profile. Each character in my book gets one of these (and there are a LOT of characters in Beginning of Arrogance). The more important the character, the more of a background they get. Krell has dozens of pages of notes on personality flaws and mannerisms and weaknesses and expressions. Lars, the fisher, has a single paragraph, since he is an extremely minor character. But whenever Lars comes up, he’s consistent throughout the book!

Your characters’ appearance doesn’t need to solely focus on hair color, either. They could have scars, tattoos, carry only an axe while another carries a sword. Whatever it is, give them a visual “marker” so that readers can better catalogue and organize the different characters in their mind. Without confusion, your readers can then focus on the most important part – enjoying your book.