Games developer Blizzard is suing a German company over software that offers gamers advantages in its popular first-person shooter game Overwatch.
It is taking legal action against Bossland at a court in California over the “cheat” tools for that and various other titles.
It said that the tools lost it millions of dollars in sales and ruined the game for legitimate players.
But the German company said a US court would have no jurisdiction over it.
“Blizzard’s business depends upon its games being enjoyable and fair for players of all skill levels, and Blizzard expends an enormous amount of time and money to ensure that this is the case,” the games developer said in a statement.
“The Bossland hacks destroy the integrity of the Blizzard games, thereby alienating and frustrating legitimate players and diverting revenue from Blizzard to defendants.”
The Bossland cheat tool Watchover Tyrant offers Overwatch players variety of features, including making enemies visible.
Blizzard already has 10 other continuing legal cases against Bossland in Germany.
But the chief executive of Bossland, Zwetan Letschew, told news site Torrent Freak that he was surprised by the latest legal action and asked why it had taken “five years” for Blizzard to act.
He added Bossland had not yet received the latest complaint.
Howard Rubin, a partner at law firm Bird and Bird, said the US court would have jurisdiction over Bossland, because “it is likely that the licence agreement is subject to US law”.
And Blizzard has previously won similar cases – notably against MDY Industries, which creates similar tools.
But Mr Rubin said Blizzard would nevertheless face an “uphill struggle” in its case against Bossland.
“They are pursuing the contractual angle – that this is a breach of the end-user agreement – and that the use of cheats induces a breach of contract, but I don’t think that they will be successful,” he said.