Blood Puppeteer

Magic Resistance. The puppeteer has advantage on saving throws against spells and other magical effects. 

Dark Puppets. The puppeteer has 12 carrionettes under its control. They act immediately after it in the initiative order. At the start of its turn, if the blood puppeteer has fewer than 12 carrionettes under its control, 1d4 of their corpses reanimate with all their hit points and rejoin the initiative order. 

Multiattack. The puppeteer makes four attacks with its strings.

String. Melee Weapon Attack: +8 to hit, reach 30 ft., one target. Hit: 7 (1d6 + 4) slashing damage. The target is grappled (escape DC 14) if the puppeteer isn't already grappling a creature. Until this grapple ends, the target is restrained and takes 3 (1d6) piercing damage at the start of each of its turns.

Unnerving Mask. When a creature the puppeteer can see starts its turn within 30 feet of the puppeteer, the puppeteer can create the illusion that it looks like one of the creature's departed loved ones or bitter enemies. If the creature can see the puppeteer, it must succeed on a DC 14 Wisdom saving throw or be frightened until the end of its turn.

The puppeteer can take 3 legendary actions, choosing from the options below. Only one legendary action can be used at a time and only at the end of another creature's turn. The puppeteer regains spent legendary actions at the start of its turn.

Slice. The puppeteer makes a string attack against a target within its reach. 

Dice (Costs 2 Actions). The puppeteer makes a string attack against a target within its reach. If this attack hits, it deals an additional 16 (3d10) necrotic damage. 

Mince (Costs 3 Actions). All creatures within 30 ft. of the puppeteer must make a DC 14 Dexterity saving throw or take 16 (3d10) slashing damage and 16 (3d10) necrotic damage.