Various aspects of the Warhammer universe
Mythic's Warhammer Online does what Mythic does best - specialize in Realm vs Realm combat. Jumping off of their achievements in Dark Age of Camelot,
Drawing inspiration from various aspects of the Warhammer universe, WAR pits the two sides -- Order and Destruction -- against each other in four battle modes that include instanced combat, skirmishes, and invasion of enemy territory ("Campaigns"). The races of Order are the Dwarfs, Empire, and High Elves; while Destruction features Greenskins, Chaos, and Dark Elves.
Unique to the RvR focus is that even PvE interaction and quests can affect the outcome of RvR combat, letting players contribute to their side even without engaging directly. There are also large sieges and keep battles, featuring up to 18 on a side. In addition to the RvR focus, the game does feature quests and other traditional leveling options. A major free update, Land of the Dead, was released in 2009 and added entire new areas, new traps, and new methods to foil the enemy.