Multiattack. Two Shadow Strikes. Can replace one with Shadow Steal.

Shadow Strike. Melee Weapon Attack: +9 to hit, 5 ft., one target, 10 (1d8+6) slashing damage and 7 (2d6) cold.

Shadow Steal. Chooses a creature it can see within 30' of it and convinces that creature's shadow to leave its owner. Target must make DC 15 Cha save or be cursed. A sleeping target has disadvantage on this check. While cursed target doesn't have a shadow and suffers one level of exhaustion that can't be removed until curse ends. Curse ends only if target convinces its shadow to rejoin with it by succeeding on a DC 15 Cha (Persuasion) check while within 10 ft. of its shadow or if shadow is returned with wish spell. While target is cursed its shadow becomes a living shade (see Creature Codex) under the shadow lurker's control. Alternatively shadow lurker can combine two stolen shadows into a shadow instead. Shadow lurker can have no more than ten living shades or five shadows under its control at one time. If a cursed creature's shadow is destroyed it becomes a mundane shadow and moves to within 10 ft. of the cursed creature and cursed creature has advantage on the check to convince the shadow to rejoin with it. If shadow lurker dies all stolen shadows return to their rightful owners ending the curses.