The Chaos Lord from the Lords of Slaughter has the Psyker (Mastery Level 1) special rule. He always knows the Prescience power from the Divination discipline. He can target any unit from the Lords of Slaughter regardless of range when attempting to manifest this power.
If you wish, you can say that any Chaos Space Marines Detachment or Formation is also a Black legion Detachment or Formation. Detachments and Formations drawn from the Crimson Slaughter may use the Warlord Traits and Tactical Objectives from the Crimson Slaughter supplement in addition to those in C:CSM and BRB.
