Silence (Death Guard)
Silence was a massive two-handed battle scythe, which was the personal weapon of the Primarch Mortarion. It was noted as being one of the most fearsome blades wielded by any of the Primarchs - though there were dark whispers that the weapon had a Xeno-tainted origin. Some familiar with the legend of the Death Guard Primarch's early life, believe that Silence was once the weapon of the terrible creature that named himself Mortarion's Father.
Millenia later during the Thirteenth Black Crusade, Mortarion still used Silence as his personal weapon while he invaded Ultramar in the Plague Wars. Despite being constantly surrounded by the filth of Nurgle's followers, the weapon always remains surprisingly clean and is still as sharp as ever.