A Call To Arms isn't your normal expansion pack, but a "Live Expansion", which will be deployed over a series of months on the Warhammer Online servers, stretching from the end of March through early June. The expansion mainly consists of three live events. First, in late March, Mythic will roll out the Bitter Rivals event, which introduces two new classes to the game, with players who complete the event getting early access to the once canceled Orc Choppa and the all-new Dwarf slayer, both brutal bezerkers and bitter rivals, hence the event's name.
Then comes an event called Beyond the Sands, which introduces players to some new concepts to be revealed later, followed by the Rise of the Tomb Kings live event in May, which will see the forces of Order and Destruction racing to unlock the Land of the Dead for their realm.
Then, in June, the deserts of Nehekhara open to players with the addition of an RVR-gated dungeon zone. Much like the Dark Age of Camelot dungeon Darkness Falls, The Land of the Dead is constantly being contested by both sides, so gaining access only means you are safe until control falls to the other side. THat's when you start sweating, knowing that hordes of enemies are on their way in.
We'll have an interview up later today with Mythic's Jeff Hickman later today, who goes into more detail regarding "Call To Arms". For now, enjoy the first few bits of art from Warhammer Online's first major expansion.