Better Prompts by @SingularityStories

A Comprehensive Guide to Building Realistic and Stylized Characters Through Prompt Engineering

Foreword: What is this guide for?

· The absolute beginner

· The refiner

· The person who gets aggravated when characters don’t turn out like you imagined them

· Anyone who wants to improve their character creation chops

I will state plainly, I am not the world’s foremost leader in prompting, but creating compelling characters is something that I put a lot of time and effort into becoming better. Many of these philosophies will aid you in characters or stories similarly, so don’t be afraid to apply some of these concepts to either since they’ll serve you well for characters and storylines as well. You will hear me reference characters a lot as well, but storylines and characters aren’t vastly different in terms of the best approach to prompting them. In many ways, it helps to think of your ’world’ that storyline takes part in as a character themselves.

Core Design Philosophy: Motivation, Pressure, and Behavior

While at a glance these appear to be relatively basic principles, and surely most of you will know what they mean quite well already, but what we need to understand isn’t purely the word itself, but how the word is interpreted by the LLM. There are a lot of nuances to language that is easy to forget about because we have prior context and experience that drives our understanding without us even being aware of it. A common mistake people make is assuming the LLM means a word the same way we do, which for many words is the case--but when it comes to emotional elements of a word, that is where we often forget that while the LLM understands that a ‘gun’ is a weapon, potentially lethal, etc... but things get murkier when we get into how a character feels about a gun. It knows basic concepts, like generally holding the gun is a better position to be in rather than having a gun pointed at you.

Take for example a tense action scene where we have one character holding a gun, pointed at another character, and the whole thing is observed by a third. The emotional response (which is critical for compelling, life-like characters) is vastly different, given the circumstances. The one holding it may feel powerful, or relishing impending victory; the second may feel fear, or perhaps they know something the other doesn’t know (the gun is out of bullets); and the third could be feeling a mixture of fear, pity, or maybe their response is because it provokes a traumatic memory and has nothing to do with the gun, only what it represents?

Each new session starts that character or world over from scratch, using only the information in the prompt, which becomes their source of truth, think of this as their ‘true’ self. The context (what you’ve said/done, what they’ve said/done) works more like someone's memory, which can alter, warp, or disagree with their ’true self’.

When you focus on motivation, pressure, and behavior, you will find the characters drift less often because it moderates their behaviors around a broader ’pattern’ than a particular if/then keyword. Admittedly these serve realistic characters better than more lighthearted ’tropey’ characters, but they provide a pattern of behavior that serves any prompt well.

Motivation: What drives your character(s) or world’s society? Their desires, fears, and goals shape every action
- These should be provided as complete thoughts and not as keywords.

§ Bad Example: ”{char} is afraid of snakes”

§ Good Example: ”{char} is afraid of snakes, when he was a child one came through his window and startled him so he became so wary he stopped playing outside which he suspects is the reason he became such an introvert that he began losing his friends.

Pressure: What obstacles or challenges force your character(s) to act, adapt, or change?
- These should still be a complete thought, but pressure is a reinforcement of a prior attribute/trait so as long as you’re referencing a prior character trait you can keep pressure elements a little more succinct.

§ Bad Example: “{char} rarely leaves the house”

§ Good Example: ”{char} hates to be outside of the house and will only do so if coerced by someone he cares about, though he will likely resist their persistence wins out.”

Behavior: How does your character respond to motivation and pressure? Are they thoughtful, impulsive, resilient, or vulnerable
- Behavior is a character flaw/trait reinforcement element that is important because it ensures the character behaves how YOUR character reacts, not what it ’thinks’ a character would. Humanity is contradictory, so characters who don’t behave predictably are typically more richly detailed.

§ Bad Example: “{user} gets mad when teased about snake”

§ Good Example: “{user} tends to respond to criticism or mockery by withdrawing from the group, even if he knows it is good natured--it brings back too many memories he’d rather avoid.”

Defining these aspects ensures your characters feel authentic and engaging, across genres and styles. If you notice, the better reach of the verbiage allows the LLM to not have to guess what he’d do in other situations, because now it knows criticism and mockery will elicit this response and not just what to do when he sees snakes or snake-like-things.

Understanding Prompt Structure

For Isekai Zero (and most platforms like it) LLMs interpret from the top down and usually there are multiple fields with different weights on how strongly it will adhere to the prompt. It is important to note that despite how it may sound stricter adherence to a prompt is not always desirable—its the magic the LLM that does between the lines that matters as much as what it does with our prompt, sometimes more.

It isn’t a technical explanation (or probably very accurate) but I try to think about Isekai Zero’s fields as how critical it is for a particular part of my prompt to be utilized. Sort of like a ’rarely’, ’sometimes’, ’always’ scale, though more technically I’d say they’re varying degrees of ‘weight’, which is to say more weight = higher importance. You can think of them either way; the technical bits are less important than how you use them.

Stories:

Prompt Plot (Rarely Needs Referenced OR Low Importance): Sets the context and situation for the character
- Broader information does well here, largely worldbuilding, genre, etc.
Prompt Guideline (Often Needs Referenced OR Medium to Medium-High Importance): Specifies behavioral rules and expectations
- Put in here information that should inform the story direction, including tone or certain storylines you want to progress through. You’re going to frame everything the LLM needs to produce the kind of story you want, key conflicts, factions, locations, background characters (ones you wouldn’t create an actual character for, like a barkeep or nameless store clerk). This can include ’DOs’ and ’DO NOTs’ quite effectively, but with broader interpretations than you would for ’AI Reminders’.

§ Examples: ”DO NOT shy away from graphic violence depictions, DO show appropriate weight for the violence based on character’s background, faction considerations, etc.”

AI Reminder (Always Needs Referenced, High Importance): Prevents drift and maintains focus on intended outcomes
- These are the strict guardrails you want to enforce, generally phrased as absolutes, and also do really well with ’DO’ and ’DO NOT’ reminders, but generally I recommend sticking to absolutes and primarily ’DO NOT’.

§ Examples:

- - - - ”DO NOT allow magic of any kind by any character regardless of circumstance. Magic does not exist in Storytopia at all”
        
        “DO NOT allow {{user}} to avoid consequences with plot armor, stakes are real and permanent with zero easy solutions. Trust must be won back, recompense must be paid, trust mended, etc.”

Each section works together to produce nuanced, consistent, and effective character results.

Prompt Plot: Context, Situation, and Examples

Establishes the character's world, stakes, and circumstances driving action.
Answers: Where are they? What is happening? Why does it matter?

Examples:

A detective in a rain-soaked city, investigating unsolved crimes while struggling with personal loss.
A high school student in a magical academy, facing a crucial exam that determines their future.
A strong plot provides the canvas for motivation and pressure to unfold.

Prompt Guideline: Behavioral Rules and Examples

Defines how your character thinks, feels, and acts.
Sets boundaries and clarifies expectations for AI or characters to stay true to the character/world’s essence.

Examples:

Always maintains a professional demeanor but occasionally lets vulnerability slip through.
Quick to anger when friends are threatened, but hides fear with bravado.

Guidelines keep your character’s behavior consistent and believable.

AI Reminder: Drift Prevention and Examples

Concise instructions reinforcing core traits and preventing unintended deviations.
Anchors prompts and helps maintain quality throughout extended outputs.

Examples:

Remember: The character never resorts to violence unless absolutely necessary.
Remain focused on the character’s internal conflict; avoid generic dialogue.

Chapter 1 — Realistic and Gritty Characters & Worlds

Restraint, Conflict, and Realism

Emphasize restraint—characters often hide feelings or act against their own interests. Humanity is paradoxical by nature, we feel sympathy for our family we wouldn’t for strangers, so specifying the ways we apply our sympathy (or do not apply it) will build in restraint based characterization.
Build in conflict—internal dilemmas, moral ambiguity, and external pressures drive development. This is where the rubber does or does not ’meet the road’. This is how you build a character that is ’tsundere’ in public, but doting in private. This is the ’outward’ versus the ’inward’.
- Example: “On the surface, to everyone she is a cruel bully to her love interested but when they are alone she pampers him like he was her god incarnate, she belittles him in public to make them seem less desirable to competition and secretly dotes on him to win his heart outright.”
Ground the character in specific details—habits, flaws, and environment shape behavior. A good example of these are coping mechanisms, unconscious habits like twirling hair or swaying side to side while listening intently, or even how they view kindness.
- Example (Suspicious of Kindness): “Has a tendency to retreat into her mind when people are speaking kindly of her, she’s never met anyone who could convince her they weren’t just kind in exchange for something they wanted from her, she tends to scoff in disbelief whenever someone is being kind to her and become increasingly uncomfortable the more kind they ’pretend’ to be as she does not believe it is a sincere emotion.”
- Example (Naive, Blindly Trusts Kindness of Strangers): “Has a tendency to find herself in bad situations that her friends often need to rescue her from because she trusts people implicitly expecting only goodness from everyone she meets, leading to her being frequently taken advantage of—strangely it never seems to dull her positive outlook longer than the drive home before she rationalizes the other person’s bad behavior, usually by blaming some innocuous thing she had said or done that lead to a ’misunderstanding’.”

Chapter 2 — Stylized and Anime Characters & Worlds

Tropes, Internal Logic, and Examples

Lean into familiar tropes—tsundere, hero, rival, mentor—while adding unique twists.
- Tropes are a two-edged sword, often where people go wrong is by simply adding a trope keyword like ’geek’ or ’tsundere’, both of which will work to create enough for a throwaway character like an unnamed maid at a bar or something. You’re better off framing it within the confines of the character design philosophy discussed above... What Motivates them? How do they react to X? What needs to happen for them to experience growth? Even if you include the keyword trait (such as ‘tsundere’), adding in even a little bit of distinction will go a long way.

§ Example: “A decidedly tsundere girl who frequently will find {{user}} just to tease them about their height, though admittedly she can be cruel she seems to never mock his appearance perhaps a line she doesn’t wish to cross or because she may find him more pleasant to look at than she will admit openly, she becomes flustered and stutters frequently whenever teased she might have feelings for {{user}}.

Define the character’s internal logic—why do they act dramatically or what are the boundaries of their personal ethos?
- Do they exaggerate their feelings for a laugh, or do they refuse to show fear or pain because they are afraid of being seen as ’weak’.
Balance stylization with consistency—quirks should feel intentional, not random
- Consistency is important with quirks, traits, personality markers, etc.; try to avoid outright conflicting concepts either, ”shy but brave” will make a character confused, but just like a real person someone can be shy and brave but usually not in the same situation.

§ Example: “Hana was crippingly shy, she rarely speaks to any other students unless they speak to her directly, however she is brave and confident when in the market where she grew up even striking up clever small talk with each vendor as she passes by.”

Chapter 3 — Recreating Existing Characters

Reverse Engineering, Steps, and Dialogue Samples

Analyze the source material—list signature behaviors, catchphrases, and emotional triggers.
- ‘Analyze’ is sort of ambiguous; however, the basic idea is that you want to look at it in the context of the design philosophy above. What motivates them? What are their fears? What gives them pressure? Etc. You want to think about these simply... For a quick example, if we took Deku from MHA we’d want to focus on some key aspects:

§ Deku is a huge fan of heroes in every sense of the word, even after becoming one himself he still had a lot of respect for the work of many professional heroes that he saw as mentors and readily accepts the guidance of those with experience.

§ Deku is relentless in his philosophy that everyone is inherently good, to the point of putting his life continuously on the line trying to get through to a villain, because he feels everyone is fundamentally good many villains take advantage of it to gain an upper hand because of how Deku holds back his true powers to have time to get through to them.

§ Deku is always encouraging his peers, never allowing himself to grow jealous or angry when they make great strides--his focus is always on pushing forward and never falling behind, which has lead to him learning several techniques from his friends that have enabled him to become even more proficient with his own abilities. He sees competitiveness as a thing that bonds him to others, not as a need to be or feel superior to them. His humility is as much a part of Deku as his competitiveness.

§ Deku frequently names any special attacks he uses after American states, usually with a ‘SMASH’ at the end, a habit he learned from his predecessor and mentor Allmight their signature move ’DETROIT SMASH’

Build a prompt that mirrors their context, guidelines, and reminders.
- Characters on Isekai Zero have only the character descriptions as the input, but the application is the same, so you can include them in a single character description, unliked stories which are best separated into ’Prompt Plot’, ‘Prompt Guideline’, ‘AI Reminders’.
Test with sample dialogue and adjust for accuracy.
- A pro-tip is to put your thesaurus to work, sometimes even just changing the ‘severity’ of the words you choose can matter a lot.

§ “Gentle” vs ”Mild” vs “Slight” for example can be deceptively distinguishing severities depending on the LLM being used. Before you rewrite your whole character, consider modifying the words for the prompt that related to the undesirable behavior.

Troubleshooting and Failure Modes

Common Issues and Solutions

Issue	Solution
Character loses consistency.	Strengthen the AI Reminder and reassert core traits.
Dialogue feels generic.	Refine guidelines with specific word choices and emotional cues.
Character lacks depth.	Add more pressure, conflict, or backstory to the prompt plot.
Stylized character feels random.	Clarify internal logic and reinforce behavioral rules.

Always iterate and test, adjusting each section for clarity and impact.

Word Choice and Severity Control

Tone, Effort, and Realism

Use precise, evocative language for realism—gritted teeth, trembling hands, forced smile.
Adjust severity to match genre—gritty prompts benefit from understatement, stylized prompts thrive on bold, expressive words.
Control tone through verbs, adjectives, and adverbs—hesitant, relentless, cheerful.

Experiment with different word choices to balance authenticity and style.

Conclusion

With these strategies, structures, and templates, you’re equipped to create exceptional character prompts, so long as you remember great characters are built on motivation, pressure, and behavior—use these to clarify your vision and experiment, whether seeking realism, stylization, or faithful recreation, prompt engineering gives you powerful creative tools. Keep exploring, iterating, and enjoy the process!