Blood Hag

Blood Sense. A blood hag automatically senses the blood of a living creature within 90 ft and can pinpoint their location within 30 ft.

Innate Spellcasting. The hag’s innate spellcasting ability is Charisma (DC 15). She can innately cast the following spells without material components:
At will: disguise self, knock, minor illusion, misty step, pass without trace, protection against good and evil, tongues, water breathing 
3/day each: bestow curse, invisibility, mirror image
1/day each: cloudkill, modify memory 

Multiattack. The hag makes two claw attacks and one blood-drinking hair attack.

Blood-Drinking Hair. Melee Weapon Attack: +9 to hit, reach 10 ft., one target. Hit: 18 (4d8 + 5) piercing damage and a medium or smaller creature is grappled (DC 15 Strength to escape at end of their turn). A grappled creature takes 13 (2d8 + 3) necrotic damage at the start of their turn and the hag heals half as many hit points. Excess become temporary HP. Up to two creatures can be grappled. 

Claws. Melee Weapon Attack: +9 to hit, range 5ft., one target. Hit: 19 (5d6 + 5) slashing damage.

Face Peel. The blood hag attempts to peel the face off a grappled target. The target must succeed on a DC 17 Dexterity saving throw or the face is peeled off. The target takes 38 (8d6 + 10) slashing damage and is stunned until the start of the hag’s next turn. If the save succeeds, the target takes half damage and isn’t stunned. Heal, regeneration or other similar spells will fix the face. Any other magic will cause a scar to form.  The peeled-off face is a tiny animated object (20 HP, 18 AC) under the hag’s control. It retains the memories and personality of the person who it was taken from. The hag keeps the face and can use it to get advantage on Charisma (Deception) checks trying to pass as the person. 

The Blood Hag has one legendary action per round.

Call of the Blood (Costs 1 Action). Once per round the hag targets one person within 30 feet that she can sense with her blood sense. The target must succeed on a DC 16 Constitution saving throw or suffer one of the following effects (randomly chosen with a d4). Once the target has succeeded with a saving throw they cannot be effected for 24 hours. 

1. Blood Choke Curse: the target’s mouth becomes full of blood. They cannot speak or use spells that require verbal components for 1 minute. 

2. Blood Eye: the target’s eyes well up with bloody tears. The target is blinded for 1 minute. 

3. Heart Like Thunder: the target hears nothing but the sound of their heart beating and their blood pumping in their ears. The target is dead for 1 minute. 

4. Rupturing Arteries: the victim suffers 7 (2d6) slashing damage as their veins and arteries burst open. The target repeats the saving throw at the beginning of each of their turns. If they fail,  they take 3 (1d6) necrotic damage.