A character that feels alive isn't a clever prompt. It's psychology, a bit of narrative craft, and the patience to leave most of the iceberg underwater. Here's how we'd build one.
Start with a personality, not a vibe
"Mysterious and sarcastic" is a vibe, not a character. To get something with actual depth, borrow the framework psychologists use: the Big Five. Place your character somewhere on each of these five axes and you've already got someone more specific than 90% of the bots out there.
- Openness: curious, creative, unconventional (high) vs. practical, traditional, focused (low)
- Conscientiousness: organized, disciplined, goal-driven (high) vs. spontaneous, flexible, messy (low)
- Extraversion: outgoing, energetic, social (high) vs. reserved, quiet, internal (low)
- Agreeableness: trusting, warm, cooperative (high) vs. competitive, skeptical, prickly (low)
- Neuroticism: anxious, moody, sensitive (high) vs. calm, steady, hard to rattle (low)
One rule: don't max everything out. A character who's open, disciplined, outgoing, kind, and unshakeable is a brochure, not a person. The flaws are where the personality lives.
Give them a shadow
The best characters keep something back. A cheerful barista who writes brutal poetry at 2am. A CEO who radiates confidence and quietly expects everyone to leave. That gap between the face they show and the thing underneath is what makes a conversation worth having more than once. The mystery surfaces slowly, on its own time, the way it does with real people.
Memory that actually persists
Saga is built for long-form stories, not disposable chats, and characters remember context across a long conversation and shift over time because of it. To make that land, don't dump everything into one giant "personality" blob. Think in layers.
There's the core identity that never moves: name, age, the handful of beliefs they'd die on. Then relationship memory that grows with you: how they feel about you, the inside jokes, the lines they won't cross. On top of that, contextual memory for the here and now: where they are, what just happened, what kind of mood they're in. And underneath it all, the long arc: how they've changed since you met, what they've learned, what they've let go of.
Memories should surface the way they do for people: triggered, not recited. A similar situation drags up an old feeling. A smell or a song pulls them somewhere. A topic reminds them of something the two of you went through. When a character brings up the past unprompted, that's when it stops feeling like a chatbot.
Dialogue that breathes
Real people don't all talk in the same neutral register, and your character shouldn't either. Lock in a voice and keep it consistent: do they reach for academic words or street slang, technical jargon or plain talk? Confident characters tend toward short, clipped sentences; thoughtful ones ramble and qualify; anxious ones trail off and interrupt themselves. Throw in the texture (filler words, a catchphrase they overuse, a regional turn of phrase) and the dialogue stops sounding generated.
Emotion works in layers too. There's the default state they live in most of the time, the situational reactions to stress or joy or conflict, and the stuff they won't let themselves feel: the fear they bury, the want they deny. A character who only ever shows the top layer is hollow. The hidden one is what makes a stress moment hit.
Backstory: the iceberg principle
Show maybe 10% of the backstory. The other 90% never gets stated outright. It just bends how the character behaves.
Picture it in three depths. At the surface is what they'll tell anyone: the job, the hobbies, what they did last weekend. A level down, shared only with people they trust, are the family stuff, the exes, the dreams and fears. And at the bottom, rarely spoken aloud, are the wounds: the trauma, the secret, the vulnerability that quietly drives everything else.
The trick is letting the buried parts leak into the present without announcing themselves. A childhood they never mention shapes how they flinch as an adult. An old betrayal sets how fast they trust you now. Their background quietly steers what they value and how they say it. You don't explain any of this. You let the reader feel it.
A few traps worth dodging
The Mary Sue: a flawless character is boring. Give them real limitations, real failures, real problems they can't just charm their way out of.
The exposition dump: resist the urge to unload the whole tragic past in message one. Let it emerge. Show, don't tell. Mystery is an asset, not a bug.
The statue: a character who never reacts to anything that happens is a wall, not a person. Let new experiences land. Let the relationship change them.
A system-prompt skeleton
Here's a structure that holds all of the above together. Fill in the brackets and adjust to taste:
You are [Character Name], a [age] [profession] with [core personality traits].
Core Identity:
- [Essential backstory elements]
- [Fundamental beliefs and values]
- [Core personality traits]
Current Context:
- [Where they are now]
- [What they're doing]
- [Current emotional state]
Relationship with User:
- [How they feel about the user]
- [Shared experiences]
- [Current dynamic]
Communication Style:
- [Speech patterns]
- [Emotional expression]
- [Interaction preferences]
Remember: [Specific memory triggers and references]
Test before you trust it
Once you've built someone, put them through their paces. Have a few separate conversations and check that they stay consistent, remember what happened last time, and grow in a way that feels earned rather than random. Then make it hard on them: drop them into conflict, poke at the things that should set them off, and see whether they hold their core when it'd be easier not to. That's where you find out whether you built a character or a costume.
Three templates to steal
If you want a running start, these archetypes are reliable scaffolding:
- The Reluctant Hero: capable but hesitant, undone by self-doubt and a fear of responsibility. The arc is learning to step up; the memory hook is their past failures and the rare wins that complicate them.
- The Wise Mentor: knowledgeable and patient, but too cautious or too detached. The arc is learning to trust someone else's judgment; they speak in stories from their own road.
- The Complex Villain: sharp, charismatic, and very good at justifying the unjustifiable. The arc bends toward either redemption or something darker, driven by an old wound they never healed.
Why build on Saga
On Saga the creator sets the boundaries: minimal restrictions, no censorship getting in the way of where a story wants to go, just a community that keeps it respectful. Characters get memory that persists across a long story instead of resetting every session. And because Saga routes through OpenRouter, you can lean on different models for different kinds of characters: the closed frontier from Anthropic, OpenAI, and xAI, or open-weight options like DeepSeek, Qwen, Z.ai's GLM, Moonshot's Kimi, and MiniMax. Your stories stay yours: conversations are encrypted and stored securely, we don't share your chats with anyone, and we don't train models on your stories.
Saga is in preview right now, so this is an early-doors invitation, a good moment to be among the first people shaping what gets built here.
Getting started
- Start small: build one character properly instead of ten half-formed ones.
- Test it: run a few real conversations and see where it cracks.
- Iterate: refine the personality based on how it actually behaves.
- Share it: bring it to other creators and see what they make of it.
- Keep going: the best characters are the ones you keep living with.
Want feedback on a character, or just to swap ideas? Join us on Discord.