Firefly Studios today announced Stronghold Kingdoms, a castle-based MMO developed for PC, will be free-to-play. Each month, players will receive a number of strategy cards. Each card has an impact on different elements of the game: agriculture, warfare, trading, religion and so on. Extra packs of strategy cards will be available to purchase to further aid players' designs on conquest. In Stronghold Kingdoms, you can rise through the ranks from humble peasant to mighty baron and beyond. Or you can become a sheriff, a governor, or even king, as you and your faction strive for victory. Stronghold Kingdoms is due to be launched in 2010.