The Mask of the Damned plays upon its victims' deepest fears and phobias. It projects hellish visions into their brains; often dropping them to their knees even in mid-charge.
Any enemy unit that wishes to assault a model wearing a Mask of the Damned or a unit of which it is part must take a standard Leadership check. If the check is failed, the unit succumbs to sheer horror, and may not make an assault this turn.