The black sands of Isstavan V burned with the fires of war at a level unseen perhaps ever in the history of the Galaxy.  Human cultures and traditions had many names for such a place, the 9th circle of Hell, Ragnarok, Armageddon.  Enough warriors to conquer a sector in weeks betrayed by those they called brothers fought for their lives, though truth they knew it was an unlikely end.  But the warriors of those three legions knew other truths; they were post-human Astartes and they would not cower