Bone Marrow. The Wretchcaster gains 1d4 hp for each humanoid that dies within 60 ft of the creature.

Heart Bone. The Wretch can still cast cantrips and 1st level spells until its skull is broken 

Spellcasting. The Wretchcaster is a 3rd-level spellcaster. Its spellcasting ability is Intelligence (spell save DC 13, +2 to hit with spell attacks). The Wretch Caster has the following warlock spells prepared:
Cantrips (at will): Chill touch
1st level (4 slots): Inflict Wounds, False Life, Blindness/Deafness                                                                            2nd level (2 slots): Ray of Enfeeblement                                                                                                                                 3rd level (1 slot): Animate Dead                                                                                                                                                

Toxic Fumes. Any creature within a 10 ft radius becomes poisoned and takes 1d6 poison damage. All food and drink in the area becomes toxic and deals 1d1 damage for each time someone eats the food.

Skull Sword. Melee Weapon Attack: +3 to hit, reach 5 ft., # target. Hit: 7 (1d8 + 2) slashing damage damage. 

Chill Touch. The Wretchcaster created a skeletal hand in the space of a creature within range. The Wretchcaster makes a ranged spell attack against the creature. On a hit, the target takes 1d8 necrotic damage, and it can't regain hit points until the start of the Wretchcaster's next turn. 

If it hits an undead target, it has disadvantage on attack rolls against it until the end of its next turn.

Inflict Wounds. It makes a melee spell attack against a creature within range. On a hit, the target takes 3d10 necrotic damage.

Ghost control. When an undead that is under the control of the Wretchcaster is swayed to attack or disobey it, they must have to take a dc15 Constitution saving throw. If they succeed, they may continue to disobey the Wretchcaster. If they fail the saving throw, they take 1d6 necrotic damage and 1d4 psychic damage. If the undead loses all its hit points from the necrotic and psychic damage, it comes back to full hit points.