The coming of the Death Guard is heralded not by trumpets but by the slow, funereal tolling of a bell, and the warrior who bears it is the Noxious Blightbringer. Pacing with grim ceremony before the advancing Legion, he swings his tocsin of misery, a great corroded chime whose mournful voice carries across the battlefield to proclaim the arrival of Mortarion's sons.
The sound is more than mere theatre. Each toll sends out a wave of entropic despair that gnaws at the resolve of those who hear it, sapping courage and hope until the enemy's hearts fail them before the first blow is struck. Where the bell rings, defenders find their spirits curdling to dread, and even hardened troops feel the cold certainty that their doom is already at hand.
For his brethren the effect is the opposite. The Blightbringer's dirge sets the cadence of the assault and lends fresh, inexorable momentum to the Legion's tread, driving the Plague Marines onward at a quicker and more purposeful pace. Certain lords prize these heralds greatly; it is said that the warlord Gothax will march nowhere without seven Blightbringers tolling in solemn attendance about him, a walking chorus of ruin.