"They came in a shattering impact. Thunder and lightning rang from the center of our camp. All was quiet for a moment as we turned and saw a crackling dome of light fade into the air. From that dome came no sound, then the terrible roar of bolters. 

The bolts slammed into men near me, turning them into mere memories of living beings. Limbs sprang from torsos, heads disappeared. The firepower was well targeted in taking down our heavy weapons first, then moving on to the company bannermen and musicians. After the first shots came a new sound- the heavy tramp of armored feet and the teeth-grating buzz of power armor...but both were deeper than those I've experienced before in the company of the Emperor's Angels.

They were seen then. Massive forms, more hunched and cumbersome power armor, clad in ebony and steel. Crimson wings and steel blades adorned their armor, and they moved without a single battle cry. No noise came from them aside from those of weapons and impact. They tore through our command squad and the Commissariat special forces. Lasblasts did nothing, power weapons were turned aside and blunted. These...monsters silently destroyed everything around them.

I've fought beside our Astartes and against those of traitorous bent, in every battle there were oaths sworn and orders roared. Even the Enemy's forces spoke in blasphemous words, that were later removed from my soul by the confessors and others of your like. Not these men, if men they truly were. That was the most sinister thing of all, for even when one took a lascannon shot to his belly and was cored out like a grox he didn't make a single sound. 

I hope to never see their like again."

-- Demi-Lieutenant Sigfur bon Friell, XIIth Davoi Blue-Korp, aftermath of the raid of Agri-Station Pilla. Report sanctioned by Inquisitorial Warrant.

Squad Belgor

The Suriel are a remnant of the Forgotten's more noble past. An order of fallen knights, now sworn to silence. Their skill in battle is well-maintained, for they are used as a hammer to crack any resistance to the Forgotten's plans. Teleporting into the midst of the enemy, the Suriel use their ancient Terminator armor to shrug off blows that would kill even other Astartes and coldly slay in a voiceless flurry of bolt, blade, and fist. 

Those wishing to join the elite brotherhood are taken before the Grand Master of the Forgotten, Beleth of Caliban. His heavy sword pierces their chest as oaths are recited and burning brands applied. Ritual stitches are sown through their lips and oath-papers affixed. The new brother's armor, created from that which was the dead and that which was taken, is bathed in clear water while he dons each piece. Then, ripping through the stitches mere moments from his helmet covering him, he speaks his last words.

Squad Furlac

"Forgotten we may be. Forgotten our lives were. Forgotten the crimes against us will never be. 
Vengeance is my purpose. Justice for our dead. Loyalty above all.
I am the nameless, the voiceless. I am of the Suriel.
Let the world mourn, for a new chapter has come." 

Squad Varcan