Silent Doom

Though the teiresi people of Noctuin have forgotten, the nations outside the Vi'Rok mountains still tell how the armies of Azlaryn would march upon their lands, killing for territory and stealing the young and fit to be slaves. Their most intimidating aspect was not the giants that led the charge, but in fact the utter silence in the soldiers. Even the nations that use reanimated corpses for their labor or armed force have been more audible.
  The soldiers of the empire would reportedly not utter a single sound, and their armor was crafted to have only the faintest noise to movement.
  It is believed that their lack in faith to any god led to the absence of souls, even in their offspring. Others think that they worshipped dark spirits who took their voices as payment for their arcane power. Where the differing opinions meet is to agree that the armies sent beyond the empires borders had lost their souls entirely to the dark forces the empire upheld to the status of godhood.

Though many would prefer to leave the empire in the past, to be forgotten like a childhood nightmare, this soulless quiet was a basis for many a child boogeyman story. Tales of how wandering away or disobeying one's parents could mean the Azlaryn would come and steal you away, or take your voice forever.
  It is not entirely embelished or unfounded, for during their campaign of terror, it was a fact that a child could be snatched up in the night without the parents being any the wiser.