Though Gul'dan was defeated at the Nighthold, and the heroes of the Alliance and the Horde recruited new allies to their cause—including Illidan Stormrage—the Legion's menace was far from over. Kil'jaeden the Deceiver, one of Sargeras' most trusted lieutenants, bolstered the Legion's defenses at the Broken Shore, hoping to use the Tomb of Sargeras and the power within it to end all life on Azeroth. The Armies of Legionfall , a special force of Azeroth's greatest heroes, fought their way into the Tomb--and found that the Deceiver had nearly accomplished his goal. Kil'jaeden transported the heroes to Argus, the fel-wrought Legion homeworld, intent on exterminating them all, but the Eredar Lord met his end at the hands of Khadgar, Velen, Illidan and Azeroth's champions. To save those on Argus and to seize an opportunity to fight the Legion on his terms, Illidan did the unthinkable—he used a device known as the Sargerite Keystone to open a rift that brought the worlds of Argus and Azeroth together. The Alliance and the Horde are now at a crossroads. They must strike at Argus with all of their might, or risk destruction by the persistent threat of the Legion.