Among the premium content is the Celtic civilization which includes a snowy northern realms, with new units including the Woad Raiders, the Druids, and the Celtic Swordsmen. Another premium civilization are the Persians, which includes the Immortals, mounted Persian Archers, and Attack Elephants.
Finally, later in 2011, the premium Skirmish Hall Booster Pack will allow players to control the battlefield, while customizing their starting Age, starting forces, beginning resources, difficulty levels, and the number of enemies to face, up to three at once.
Age of Empires Online will be available from Live for Windows Marketplace.