RALEIGH, N.C. — Rogue online gamers have designed, sold or used computer code to crush competitors playing the popular “Fortnite” survival video game, spoiling the experience and the creator’s profit potential, the game’s maker charges in a series of lawsuits.

Cary, North Carolina-based Epic Games has sued three Americans and six foreign gamers from Sweden to South Africa for hacks that undercut the game played by more than 10 million players worldwide. The lawsuits, which were filed in North Carolina and California, allege violation of the game’s copyright and terms of use contract. One of their targets may be a 14-year-old Delaware boy.

Cheating gamers are able to overpower their opponents by using tools that allow them to see through solid objects, impersonate other players and make moves other players cannot, according to one lawsuit. Up to 100 people can play the game at a time.

When cheaters “gain an unfair advantage, they ruin games for people who are playing fairly,” Epic Games spokesman Nick Chester said in an emailed statement. “We take cheating seriously, and we’ll pursue all available options to make sure our games are fun, fair, and competitive for players.”

“Fortnite,” which costs nothing to play online, generates revenue by charging players for cosmetic options, like different outfits for their virtual character, which don’t give players an edge against rivals. Some video-game makers are aggressively cracking down on cheaters, who they fear could drive away eyeballs from advertising some developers sell, said Kevin Greene, who teaches entertainment law at the Thomas Jefferson School of Law in San Diego.

“From the perspective of these game makers, it’s a big disruption,” Greene said.

None of the nine defendants could be reached for comment. Two U.S. residents in Louisiana and Minnesota and one Canadian did not have listed telephone numbers matching addresses where court summonses were sent. Two Russians, one Ukrainian, one Swede and one South African did not respond to emails sent to addresses listed in court documents. The Minnesota man, Charles Vraspir, is negotiating a settlement to the lawsuit, Minneapolis attorney Mick Spence said.

But in a letter to the North Carolina federal judge hearing one case, a Newark, Delaware, woman described one defendant as her 14-year-old son. Lauren Rogers said in the letter that the boy didn’t modify “Fortnite,” but instead obtained the tools from an easily accessible public web site that Epic Games should be suing instead. As a minor, the boy isn’t able to agree to the terms and conditions of using the game, she said.

“They are using a 14 year old child as a scape goat (sic) to make an example of him,” Rogers said. There was no answer at a number matching Lauren Rogers’ address.

The Epic Games spokesman did not answer when asked whether the company knew the player it sued was a minor before filing its case. The lawsuit said the boy has used fake names to keep playing “Fortnite” despite being banned more than a dozen times and posting videos on YouTube showing himself using the illicit software and displaying links to a web site distributing the cheats.

“Epic is not okay with ongoing cheating or copyright infringement from anyone at any age,” Chester said in an email.

He didn’t respond when asked whether the company has also sued web hosting or other companies used to distribute the cheating code, or how those targeted were identified.

A 1990s-era update to federal copyright law sets up procedures where companies can demand that online service providers like YouTube remove material that violates the companies’ rights. The person or company that posted the challenged material can counter with a statement that the material isn’t illegal. But it’s largely unknown that challenging the takedown notice can give U.S. courts jurisdiction over foreign residents in the dispute, said Xuan-Thao Nguyen, who teaches intellectual property law at Indiana University.

Greene said the video-gaming lawsuits remind him of the 1990s, when music licensing organizations aggressively enforced copyrights, even for campfire sing-alongs.

“I think legally they were right but the backlash against them was enormous,” Greene said. Video-game makers “have to be careful from a public relations standpoint that, yeah, they might win the battle but they could lose the war.”