Vigilators

The Vigilators are the blade-sisters of the Silent Sisterhood, wielding the great two-handed executioner sword in the close and bloody work their bolter-armed kindred cannot finish from afar. Like all their order they are Nulls, untouchable pariahs whose soulless presence fights alongside the Adeptus Custodes as a living ward against sorcery, and the Vigilators carry that dread quality into the very heart of the melee. They stalk the battlefield seeking out the enemy's psykers and warp-touched champions, the very foes most lethal to ordinary troops, and behead them with single ritual strokes before their fell powers can be brought to bear. To a witch there is no more terrifying sight than a Vigilator's silent advance, for she looses her sorceries only to watch them wither to nothing, then turns to flee only to find the greatblade already falling. Swift, wordless and utterly without mercy, the Vigilators clear a path through the enemy's mightiest warriors so the golden ranks of the Custodes may march unhindered toward their sacred purpose. Their silence amid the slaughter is more chilling than any war-cry.