The Black Echelon was a covert cell of Taldan agents in the early 40th Century AR who were tasked with infiltrating the defenses of Absalom in preparation for the Silent Tide. Their mission was to weaken the city's defenses and alert systems, paving the way for the larger naval invasion. Their plan was uncovered and the leaders of the group, who were to signal the rest of the cell into action, were assassinated. The remaining members of the Black Echelon were put to the sword after the Absalom navy dispatched the Taldan fleet to the last mast.
Each member of the cell had taken an ancient oath, known as the Binding Word, prior to deployment, which guaranteed their service to the mission despite any obstacle, including death. In 4708, eight centuries after taking the oath, the Black Echelon were raised as silent, misty undead to carry out their original mission.
See also: Black Echelon operative