Tower Alliance Online is a full scale online RTS (real time strategy) game based on tower defense, a genre already popular with gamers. TAO has two distinct themes: Space Fantasy (henceforth known as SF) and Elemental Magic (henceforth known as EM). Various types of towers and upgrading systems exist in the SF theme. In contrast, tower combination and highly individual skill systems exist in the EM theme, allowing for virtually unlimited ways of enjoying the game through various new combinations that reflect the players’ attributes. Furthermore, the user-friendly interface provides easy access to the game for all users. Tried and tested qualities of the tower defense genre will provide maximal gaming pleasure for everyone.