Best AI NPC Tools for Unity in 2026
Unity is still where most AI NPC experiments start, and the options have changed a lot in the last two years. Inworld retired its Character Studio, Replica Studios shut down, NVIDIA went all-in on Unreal, and voice APIs got good enough that some teams build everything themselves.
This guide compares the main ways to add AI characters to a Unity game as of October 2026.
Quick comparison
| Tool | Unity support | Character editor | Voice | Local AI | Best for |
|---|---|---|---|---|---|
| Neocortex | Unity SDK with 6 sample scenes, WebGL microphone support | Visual node editor | TTS, STT, cloning, design | Local LLMs via Ollama, self-hosted for studios | Teams that want designer-owned characters in Unity fast |
| Convai | Unity plugin | Web dashboard | Yes | Enterprise on-prem only | Training sims and XR with avatars |
| Inworld | New Runtime SDK; legacy Asset Store SDK deprecated | No (Studio retired) | Strong TTS | No | Teams that want voice infrastructure and will code the character |
| Charisma.ai | Unity package from GitHub | Story graph | Yes | No | Branching narrative experiences |
| LLMUnity | Native, open source | No | No | Fully offline | Programmers who want offline text generation |
| Player2 | Unity SDK | No | Yes | No | Free hobby and jam games |
| ElevenLabs Agents | No Unity SDK | Workflow builder | Excellent | No | Voice agents outside games |
| OpenAI Realtime | No official Unity SDK | No | Yes | No | Teams building their own stack |
| NVIDIA ACE | No Unity plugin | No | On-device | Yes, on RTX | Unreal studios, not Unity |
The three approaches
1. A complete character platform
You design characters in a tool, then call them from Unity through an SDK. Neocortex, Convai and Charisma.ai work this way. This is the fastest route to a shipped feature, because voice, memory, session handling and character consistency are maintained for you.
What separates them is who controls the character. Neocortex builds each character as a visual graph: personality, emotion, knowledge, world, intents and actions are nodes a designer can edit and test in the browser. Convai centres on embodied avatars and simulations, and Charisma on authored story graphs.
2. A local inference library
LLMUnity runs models offline inside your build. It is free and private, but it is a library, not a character system: there is no voice, no editor, and you choose, ship and tune the models.
3. A raw model or voice API
OpenAI Realtime, ElevenLabs Agents and Inworld's Runtime give you excellent models and voices. In Unity you write the audio client, the key-issuing backend, the character prompts, memory, guardrails and game integration yourself. That is a real engineering project, and it keeps going after launch as models and prices change.
What to look for in a Unity AI NPC tool
- Unity version and platforms. Check that it supports your Unity version and your targets, especially WebGL, where Unity has no built-in microphone support.
- Who can edit characters. If only programmers can change a character, every dialogue tweak waits for an engineer.
- Gameplay hooks. Characters should be able to trigger actions and react to your scene, not only talk.
- Voice. Speech-to-text and text-to-speech built in, ideally streamed.
- Cost model. Per-message, per-minute and per-player pricing behave very differently once players start talking.
- Exit options. Can you prototype locally or self-host if you need to?
Our recommendation
For most Unity teams shipping a game, a character platform beats building your own, and Neocortex is built specifically for that job. You get a visual editor your designers can use, an SDK with sample scenes for text, voice, actions, interactables and multi-character chat, voice cloning, WebGL microphone support, and a path to local models and self-hosting.
Related comparisons
All competitor details were last checked in October 2026.
Written by
Sercan Altundas
Date
Oct 17, 2026
Read time
6 min
