Beyond the Dark Portal

With Gul'dan dead and the Horde imprisoned, old Ner'zhul gathered the orcs who remained on Draenor. He reopened the Dark Portal and sent raiders into Azeroth to steal powerful artifacts, hoping to open gateways to new worlds where his people could escape.

The Alliance answered with an expedition through the portal under Turalyon and Khadgar, joined by the ranger Alleria Windrunner, the dwarf Kurdran Wildhammer and the warrior Danath Trollbane. They fought the new Horde across Draenor, but Ner'zhul's portals were already tearing the world apart. To save Azeroth, the expedition destroyed the Dark Portal from the far side, trapping itself in the shattered remains that would become Outland.

Ner'zhul escaped through one of his rifts, straight into the hands of Kil'jaeden. The demon tore away his body but kept his spirit, bound it into enchanted armor and sealed it in a block of ice together with the runeblade Frostmourne. Hurled into the frozen wastes of Northrend, the Frozen Throne became the seat of a new power: the Lich King, whose task was to spread a plague of undeath and soften Azeroth for the Legion's return.