Realm of Chaos: The Lost and the Damned (1990), p197 — Chaos Army of Nurgle

The approach of a Chaos Army of the Patron Power Nurgle is foreshadowed by a dark plague of flies. These flies are part of the army, and live upon the foulness of the horde itself. During the battle, the flies congregate into an especially dense mass around any one enemy unit, causing much inconvenience as they buzz into the eyes, ears, and mouths of the enemy. The Army of Nurgle uniquely includes units of undead. The body of a plague victim belongs to Nurgle, should he care to claim it, for a year and a day. As the army advances, plague victims burst from their graves in the form of Zombies and Skeletons, ready to serve the Lord of Decay.