Monarch Skeleton

Master Tactician. The monarch skeleton and any skeletons within 30 feet of it have advantage on attack rolls against a creature if at least one of the skeleton's allies is within 5 feet of the creature and the ally isn't incapacitated.

Sovereign's Command. As a bonus action, the monarch commands a skeleton within 30 feet of it to make one attack as a reaction against a creature the monarch attacked this round.

Turning Defiance. The monarch skeleton and any skeletons within 30 feet of it have advantage on saving throws against effects that turn undead.

Multiattack. The monarch skeleton makes two dreadblade attacks.

Dreadblade. Melee Weapon Attack: +9 to hit, reach 5 ft., one target. Hit: 14 (2d8 + 5) slashing damage plus 7 (2d6) necrotic damage. If the target is a creature, it must succeed on a DC 17 Constitution saving throw or its hp maximum is reduced by an amount equal to the necrotic damage taken. This reduction lasts until the creature finishes a long rest. The target dies if this effect reduces its hp maximum to 0.

Grasp of the Grave (Recharge 5-6). Each non-skeleton creature within 30 feet of the monarch must succeed on a DC 16 Dexterity saving throw or be restrained by ghostly, skeletal hands for 1 minute. A restrained target takes 10 (3d6) necrotic damage at the start of each of its turns. A creature, including the target, can take its action to break the ghostly restraints by succeeding on a DC 16 Strength check.