Ordo Sinister

The Ordo Sinister, one of the most secretive and detached Legios of Titans ever to serve in the Imperium stride to battle in an eerie silence. Often being referred to as the Left Hand of the Emperor, the Nightmare Titans are no stranger to being deployed alongside the Legio Custodes,  or Legio Ignatum, fighting in a strange unison, with battle-plans and strategies going unconfirmed, but seemingly acknowledged when in the midst of the battle. Even the Custodes, the oldest and most loyal warriors in service to the Master of Mankind, have never fought alongside such a unknown Agency of the Imperium. However, when the Psi-Titans of the Ordo Sinister are deployed into the anvil of war, they command such a fear in the enemy that often times their mere presence is enough to quell the hostile force to nothing more than a fleeing rabble. To say that the Titans of the Ordo Sinister are awe-inspiring would be an understatement, with each Titan being such a masterpiece of war; in such a manner that cannot be fully appreciated from the written word of any remembrancer who may claim to have witnessed these magnificent Titans in battle. 

In Smaugonite's Ordo Sinister collection, there is the Titan listed below:

TENEBRAE ET SPIRITUS (Warlord-Sinister Class) #1091

 ...+++Reinforcements incoming+++...