Brendan "PlayerUnknown" Greene invented the battle royale game mode long before he turned it into a standalone game with PlayerUnknown's Battlegrounds. But for all of the battle royale mods and games that exist, PUBG has been far more successful: The game has smashed all-time records on Steam and enjoyed a meteoric rise, with no end in sight. As you'd expect, other companies are looking to capitalize on the interest in PUBG, but the game's developer is unhappy with the particular approach Epic Games is taking with a new mode in Fortnite.

Epic announced earlier this month that it was releasing a new battle royale-style game mode for its upcoming free-to-play game, Fortnite. It made no attempt to hide its obvious inspiration, naming the mode Battle Royale and stating in a blog post, "We love battle royale games like PUBG and thought Fortnite would make a great foundation for our own version." After initially opening it only to those who purchased the early access version, Epic recently revealed that it will offer this aspect of the game for free to everyone starting on September 26 (the entirety of Fortnite will be free-to-play beginning next year).

In a curious move, PUBG developer Bluehole has now spoken out about the mode, even going so far as to release a press release sharing its reaction to Epic's announcement. The press release, which refers to PUBG as "the first standalone Battle Royale survival shooter game," states that it's decided to respond to "growing concerns regarding the similarities between the battle royale mode in Epic Games' newly revealed Fortnite and PUBG."

"We've had an ongoing relationship with Epic Games throughout PUBG's development as they are the creators of UE4, the engine we licensed for the game," said Bluehole VP and executive producer Chang Han Kim. "After listening to the growing feedback from our community and reviewing the gameplay for ourselves, we are concerned that Fortnite may be replicating the experience for which PUBG is known."

The press release notes that PUBG developers have "no relationship to Fortnite's development as concerns around User Interface (UI), gameplay, and structural replication in the battle royale mode exist."

Han Kim also took issue with Epic mentioning PUBG in reference to Fortnite's new mode. "We have also noticed that Epic Games references PUBG in the promotion of Fortnite to their community and in communications with the press. This was never discussed with us and we don't feel that it's right."

He also issued a threat, suggesting that Bluehole could attempt to take some "action" against Epic. "The PUBG community has and continues to provide evidence of the many similarities as we contemplate further action," Han Kim said.

No further specifics were shared, and it's unclear whether Bluehole has any intention of actually pursuing legal action. In light of PUBG's massive success, it's no surprise to see other developers looking to it for inspiration. As the press release even points out, Greene discussed copycats in a recent Reddit AMA.

"Other companies will, of course, enter the marketplace, but I would just hope they put their own spin on the game mode and not just make a carbon copy!" he said in response to a question (which didn't specifically mention Fortnite). "I try not to worry about them to be honest and instead just concentrate on completing my vision for a battle royale game."

We've reached out to Epic for a response to Bluehole's comments. We'll report back with anything it has to share.