Q: Why do some Alliance soldiers raised by the Forsaken immediately become loyal to the Forsaken while others do not? Are they being mind controlled? If so, by whom: Sylvanas or the Val’kyr? How does this relate to the fact that the Forsaken cultural identity is based on their free will and rebellion against the Lich King?
A: Free will is one of the cornerstones of Forsaken culture, with the great capacity for both good and evil that it entails. However, some undead, especially those who die in combat or under extreme stress and are raised soon after, enter into a violent, frenzied state. Undead in this state are easily manipulated and their rage is often directed at the foes of those who raised them. After the effects wear off, if the risen corpse has not been destroyed, they are given the same ultimatum that other Forsaken are offered: join the Dark Lady or return to the grave.