Originally Posted by
Venziir
The Forsaken broke the control of the Lich King and regained their free-will. But the Forsaken are not your average skeleton or zombie, they are special undead, either fallen heroes, magisters or rangers. The abominations in their armies are their own creations, thus they are not bound to the Lich King.
Oh and the Old God in WC3, was NOT an Old God, but a Forgotten One, which is just a big blob of uglyness. Also, the encounter was not mentioned in the Arthas novel, so it has most likely been removed from the lore.