Welcome to Librarium Online!
I'm just getting into WFB and have been drawn to the beauty of the Vampire Counts. One question I have is looking in the armybook, who can be a general for your army; I know it says necromancers and thralls with necrarch bloodline power can be, but does that mean that they are the only two units that can be the general? any help would be appreciated.
Undead army generals have to be wizards. Thralls, Wights, and Wraiths don't have a magic level and so they cannot be the army general. The only exception is a Thrall with the Nehekhara's Noble Blood power which grants him/her/it a magic level of 1 and therefore the ability to lead an army.
That means Vampire Lords, Vampire Counts, Master Necromancers, Necromancers, and Necrarch Thralls with that particular bloodline power are your options.
Remember that the model with the highest leadership is your general by default, if they can be general that is.
ah that explains it.. thanks zanzibar!