Reikenor the Grimhailer (Easy to Build)

Once a sorcerer-king rich in the knowledge of amethyst magic, Reikenor ran afoul of Nagash. Now, in undeath, the Grimhailer is cursed to serve the Great Necromancer, acting as his chief reaper of souls. There are few sights more ominous than the macabre wraith-wizard atop his winged steed, lit by the eerie light of his corpse candles. Through his incantations, Reikenor can summon a wraithstorm - a cyclone of amethyst magic that stirs those souls recently separated from their bodies. His spell incites them to savagely attack their former comrades, a hurricane that hacks and pulls down the living; thus is a dark vengeance delivered to those who would thwart Nagash.