PUBG Corporation had previously suggested that it could enact legal actions against copycats. At the time the beef seemed to be with Fortnite, but now the company has focused on the two PUBG 'clones' released by NetEase for mobile devices: Knives Out and Rules of Survival. As discovered by TorrentFreak, a lawsuit has been filed in the US District Court - Northern District of California for the complaints of copyright infringement, trade dress infringement, and unfair competition.

　　Here's an example of the actual complaints made in the 155-page document against Rules of Survival (those against Knives Out are basically the same).

Copying in Rules of Survival Game

　　50. On information and belief, Defendants created ROS by copying BATTLEGROUNDS and with the intention of creating a version of BATTLEGROUNDS for mobile devices.

　　51. On information and belief, Defendants intended to create consumer confusion as to the source of ROS and intended to cause consumers to believe, incorrectly, that ROS had been developed by PUBG. On information and belief, Defendants intended to misappropriate consumer goodwill toward PUBG in order to market and gain economic benefit from ROS.

　　52. On information and belief, there has in fact been confusion in the marketplace as to the source and origin of ROS, with consumers believing, incorrectly, that ROS was developed by PUBG. For example, ROS has been referred to in the marketplace as “PUBG on Mobile,” “Mobile PUBG,” and the “BEST MOBILE PUBG”.

　　53. On information and belief, commentators in the industry have characterized ROS as a copy, “rip-off,” “knock-off,” or “clone” of BATTLEGROUNDS. For example, one industry commentator observed that “fans viewed the game [i.e., ROS] simply as a rip-off of the highly successful ‘PlayerUnknown’s Battlegrounds (‘PUBG’)” because “[e]verything about it screamed ‘PUBG’ as the majority of its elements seem to have been taken from the popular Xbox One title.”

　　Other industry commentators have repeatedly characterized ROS as a

　　“clone” or “knock-off” of BATTLEGROUNDS, or “[h]eavily modeled after” BATTLEGROUNDS.

　　54. On information and belief, the ROS app can be downloaded to a mobile device free of charge, and the ROS game can be played free of charge. On information and belief, Defendants have released ROS into the marketplace at or below cost for the purpose of gaining market share before PUBG releases BATTLEGROUNDS for mobile devices.

　　55. ROS contains many elements that are substantially similar to copyrightable elements of creative audiovisual expression in BATTLEGROUNDS.

　　It seems rather unlikely that a similar lawsuit could conceivably be filed against Fortnite Battle Royale with a reasonable hope to succeed, given that Epic's game is much further apart on everything from visual style to gameplay elements.