The Morghast Archai are older than the legions they now march beside, shaped by Nagash himself in ages past to serve as his heralds and executioners. Sheathed in ensorcelled armour and borne aloft on vast skeletal wings, they descend upon battle-lines like verdicts, their great halberds shearing through champions the way a scribe strikes an error from a page.
Within the Ossiarch hierarchy the Archai stand guard over Katakros, the Mortarchs, and the empire's most sacred works — and they serve as punctuation. When Nagash wishes an example made, the Morghasts are the seal upon the sentence, and even the deathless legions grow quieter when those shadows cross the bone-fields. The living have no word for what they feel at the sight; the dead, perhaps wisely, have surrendered all their words already.