In the relentless economy of bone that sustains the Ossiarch legions, purity is everything. The Emissarian agent Thanatek scours the Mortal Realms in search of truebone - osseous matter of exceptional quality, worthy of the tithe demanded by Nagash’s empire. To harvest such relics, he leads a grim retinue of corpse-reapers who slaughter, harvest, and catalogue the remains of the worthy.