Japanese mobile giant DeNA has been ramping up its US presence for several months. Part of its strategy is to acquire a number of Western companies. The latest is Astro Ape, which makes Office Heroes for the iPhone.

The larger plan for DeNA Global (the American subsidiary) is to create a new platform, MiniNation, as well as find content to take back to its successful Japanese mobile social network, Mobage Town. Instead of persuading developers to try out the platforms, DeNA is buying them outright.

DeNA also recently acquired GameView, which made a series of mobile social games, and Icebreaker, as well as making an investment in Aurora Feint and opening a $27.5 million fund for Western developers.