Going for two deals in a week, Korean online game publisher Nexon has entered into exclusive negotiations to acquire online game developer GameHI, a maker of a popular first-person online shooter game.

Nexon is one of the leaders in the free-to-play online game business. Its games are free, but you pay for virtual items such as weapons with virtual currency that you buy with real money. That business model has now become popular in the U.S. and is expected to generate $1.6 billion in revenue in the U.S. this year, according to Inside Network. Nexon’s popular games include Maplestory, Dungeon Fighter Online, and Mabinogi.

GameHI makes massively multiplayer online games, or persistent worlds, such as the first-person shooter game Sudden Attack. Earlier this week, Nexon said it was acquiring Korea’s Ndoors, another maker of MMOs such as GoonZu Online. The price was not disclosed in the Ndoors deal, and a price hasn’t yet been set in the GameHI negotiations.