Atlus Online don’t just run MMORPGs, they also run an MMORTS (massively-multiplayer online real-time strategy game). Knights of the Sky is a browser-based MMORTS that went into open beta this past week.
Knights of the Sky is a free-to-play game. You don’t have to download a client to play it either; it’s an entirely browser-driven title, and the open-beta will be used by the developers to improve the game before its official launch.
You can learn more about Knights of the Sky and register for the open beta on the game’s official website.