Epic Games announced on Tuesday that Unreal Editor for Fortnite (UEFN) will include a new tool allowing developers to create generative AI-powered non-player characters (NPCs). Voice types, delivery styles, and personality traits will be customizable.
The announcement occurred during Epic’s “State of Unreal” keynote, where a live demonstration showcased the technology. The NPC, named Mr. Buttons, was designed to persuade players to press a large red button and created using approximately 20 lines of prompt text. During the presentation, the NPC generated responses in real-time.
According to a demon, when the presenter asked about signs discouraging pressing the button, Mr. Buttons responded, “Signs, you say? Mere suggestions from those who lack imagination. After all, rules are made to be gently nudged aside. Wouldn’t you agree?”
The demonstration highlighted limitations of the current technology, including its turn-taking nature, rather than live, uninterrupted dialogue. The presenter was required to hold a button to activate their microphone. Mr. Buttons paused to process after each question, which the AI tried to mask with vocal fillers.
This technology builds upon the recent integration of Darth Vader in Fortnite: Galactic Battle. Gemini 2.0 Flash generated Darth Vader’s dialogue, and ElevenLabs AI tech was employed to replicate the voice of James Earl Jones, with approval from his estate.
The AI-driven Darth Vader experienced issues, as a widely shared video showed the character using an expletive following a streamer’s voice prompt including the words “freaking” and “fucking.” Darth Vader repeated those words and then scolded the player for using harsh language. Epic Games released a hotfix after the incident.
Fortnite creators will be able to create their own NPCs in the UEFN Editor later in 2025.
