From the campaign:
Only the most knowledgeable of mages, ones that have never wavered before the enemy, fighting shoulder to shoulder with other templars from the front, may be intro¬duced to the inner circle of the Dark Guard. The sorcerer wishing to command brothers bearing the mark of the betrayer must possess immense presence and courage to lead them into battle. Not unlike anything connec¬ted with the Scarlet Watch, being placed in charge of its unit is not cause for celebration. As it often happens, order command assigns certain politically inconvenient mages to the Guard, sending them away to the border¬lands to fend off barbarians... In spite of this ostracism, they enjoy enough trust to be allowed access to necro¬mantic tomes, a fact which reflects in the spells they cast.