AI Characters that remember.
Build NPCs that hold grudges, spread gossip, and build relationships across every player session. Backed by persistent world infrastructure that keeps every interaction, emotion, and trust level alive.
How the platform is organized
Persistent world primitives describe your world. The platform foundation runs and connects them. Products are built on both.
Products
Built on the primitives and the foundation
Persistent world primitives
The foundation of your world’s state
Identity and relationships
Who is in your world, who knows whom, and how they feel about each other.
- Player and NPC identities
- Per-player trust, patience, and mood
- NPC-to-NPC trust
Persistent state
What each entity carries from one session to the next.
- Per-character memory
- Relationship state
- Identity state
Information flow
How what one entity knows reaches another.
- Sharing between characters
- Sharing presets and trust thresholds
Canon
What is true in your world.
- Per-NPC knowledge files
- Scene context
Platform foundation
Runs the primitives and connects your game
Control plane
Projects, team access, and keys.
- Projects
- Team invites
- API keys
Developer platform
How your game connects.
- Unity, Unreal, Godot, and Web SDKs
- REST and WebSocket APIs
- Dashboard and Playground
- Cloud or Local per project
Products on the platform
Built on the same identities, relationships, and state.
MistScale AI
AI Characters
Characters that read and write persistent entity state: they remember each player, change with each relationship, and pass on what they learn.
- Per-player memory
- Mood and emotion
- Trait drift
- Grounding
- Scene context
- Voice
- Arc on device
- Bring your own model
Local inference
Run characters on the player's device.
A project can generate replies in the cloud or locally, inside your game. For local projects, MistScale still builds each prompt from the character, its knowledge, and its relationship with the player. The model on the device writes the reply.
Our model
Arc
A language model fine-tuned for in-world characters, running on the player's device.
- Type
- Fine-tuned LLM
- Runs on
- The player's device
- Engine
- Unity
Ready to run
Arc is tuned on the way MistScale describes a character: traits, mood, trust, and what it knows. The Unity SDK downloads it for you.
Bring your own model
Ship your own GGUF in one of five families: Qwen 3, Llama 3, Mistral, Gemma 4, or Phi-4. MistScale builds the prompt in that family's format. The model and its licence stay yours.
Cloud or Local, per project
Pick where replies are generated when you create a project, and change it later from the project overview. Every character in a project runs the same way.
Local inference is in the Unity SDK today; the Web, Godot, and Unreal SDKs run cloud projects. Local replies have no grounding check and no voice, and the Playground works with cloud projects only.
You decide who gossips.
And who they trust.
Word spreads between your characters, but only along the lines you draw. Set each one to Never, Cautious or Open, and set how much they trust each other.
Event
A player burns the village mill.