I have not played Warhammer 40,000 , but I have always assumed that Necrons caused Fear like the Undead in Warhammer Fantasy Battle . I personally find them to be terrifying.
Shouldn't they have a Fear rating in the roleplaying games? Would it break anything if they did? Should it be the same rating for Warrors, Immortals, Flayed Ones, Lords, Deathmarks, and the Lych-something-something-Guards?