Fortnite's Darth Vader is AI-powered. Voice actors are rebelling.

Months after the death of James Earl Jones, the booming voice of Darth Vader, Fortnite players are having in-game conversations with the Star Wars villain about being a Jedi and his conflict with Obi-Wan Kenobi.

Sometimes his responses have been witty: "I sense no connection to the force within you." Others were comedic, with Darth Vader telling one curious player that lightsabers were weapons, "not gardening tools."

Thank -- or blame -- artificial intelligence.

A few years before Jones died, he agreed to let AI learn from archival recordings of his vocal performance, and his estate has publicly supported the actor's presence in Fortnite. But the new collaboration has been contentious because of a larger battle over AI that has led actors to strike against video game companies for more than nine months.

SAG-AFTRA, the union representing tens of thousands of actors, filed an unfair labor practice charge Monday that said the use of AI to generate Jones' voice in Fortnite had violated the union's right to negotiate changes to its bargaining agreement.

The charge, which was filed with the National Labor Relations Board, accuses Llama Productions, a subsidiary of Epic Games, of "making unilateral changes to terms and conditions of employment" without providing notice to the union or allowing the opportunity to bargain.

David Hoppe, a managing partner at Gamma Law, a law firm that focuses on media and technology industries, said the complaint was subject to challenge on a number of fronts.

"But the goal here may be principally to bring public attention back to the issues of performers' rights and the challenges of AI in video game production," he said in an email.

Epic did not respond to a request for comment. A union spokesperson said AI use that displaced workers needed to be bargained.

"While the union is generally very supportive of employers' use of AI as a tool to enhance the audience experience, employers cannot implement use of such tools without involving the union first," the spokesperson said in a statement. "If they fail to do so, the union will seek to hold them accountable."

The union said in a news release that it celebrated the right of estates to control the use of digital replicas but that it had to protect working actors, including those who had previously matched Darth Vader's voice in video games.

When Fortnite players talk with Darth Vader, their audio is sent to Gemini, a conversation chatbot created by Google, to generate a response from the character, Epic says on its website. After clips of Darth Vader cursing and using inappropriate phrases circulated on social media, Epic said it had issued a fix to prevent such occurrences.

The Jones family said the actor's voice was inseparable from the Star Wars story.

"He always wanted fans of all ages to continue to experience it," it said in a statement. "We hope that this collaboration with Fortnite will allow both longtime fans of Darth Vader and newer generations to share in the enjoyment of this iconic character."

Whether the union's complaint will be successful remains to be seen. But William Watson, a professor of learning design and technology at Purdue University, said that now was the time to have this fight.

"If you look at social media and tech companies, it's very clear that society cannot trust them to be making decisions outside of their best interests," he said, pointing to the number of times that Meta has been accused of using features that hook children to its platform.

He likened the moment to Pandora's box.

"Before we open it, we need to understand what sort of guardrails we need put in place, both in terms of ethics of the algorithms and in terms of displacement of people's jobs and careers," Watson said. "That's certainly coming down the line across all sorts of industries. But ultimately, AI is here to augment what we as humans can do, not just be a detrimental force and replacing people."