Yes, Ghazghkull's save does indeed become invulnerable when he activates
HIS whaaaaagh!
This is not to be confused with the wierdboys whaaagh! or the basic whaaaagh! any warboss can kick off.
Buy you already knew this
The save does however not remain invulnerable very long, it remains invulnerable for the duration of the turn the Whaaaaagh! was activated in and the turn following this, after that his save reverts back to the shoddy ol 2+ armour save any ol mega nob has
Then we have the age ol issue of weapons that ignore
inv saves but not normal saves... I dont want to get into this one as I honestly dont know what the current take on it is.
Have there been an official
FAQ on this?