The shamans of the orc tribes that escaped grew concerned over a newborn child with a prophecy. Fearing she would be too young to face the troubles already surrounding them or worse that she could be corrupted, they sought a means to ready her ...quickly.
Klass Metalfist knew of a way from Old Draenor having watched the warlocks rapidly age young orcs into savage warriors. He not only knew how but how to do it better without some of the drawbacks - but at a price.
Playing on their fears, he created an amulet in exchange for materials and labor to build a fortress far away from the eyes of Orgrimmar. As Klass' power grew, he sought to build an alliance with the Magram, a tribe of savage centaurs, and consolidate his power to eventually overthrow Thrall. The Magram had their own problems...competing tribes to the south and the roaming Tauren to the north and east occupied them. The centaur were also superstitious and eschewed Klass' "magic" as taboo until he convinced a few of its untapped power.
Now Klass needs the power of the amulet he fashioned to make a final demonstration to the Magram Khan and secure more support. He arranges through his spies to capture the child, now a young adult warrior. Should he succeed, his combined warlock and centaur army would threaten the gates of Orgrimmar.