BG3 Mistress of Souls

Sculpt Spells. When the mistress casts an evocation spell that affects other creatures that it can see, it can choose a number of them equal to 1 + the spell's level. The chosen creatures automatically succeed on their saving throws against the spell, and they take no damage if they would normally take half damage on a successful save. 

Grave Magic. The mistress's spell attacks deal an extra 4 (1d8) necrotic damage. 

Spellcasting. The mistress is a 5-level spellcaster. Its spellcasting ability is intelligence (spell save DC 17, +7 to hit with spell attacks). The mistress has the following wizard spells prepared:
Cantrips (at will): Chill Touch
1st level (2 slots): Mage Armor
3rd level (1 slot): Fireball

Multiattack. Makes two flail attacks.

Myrkulite Scourge. Melee Weapon Attack: +4 to hit, reach 5 ft., one target. Hit: 5 (1d8 + 1) bludgeoning damage plus 3 (1d6) necrotic damage. 

Incubate Death. The mistress creates a skeletal involucre within 30 feet it. The involucre is a medium sized object with a 10 AC, 24 hit points, and an immunity to necrotic, psychic, and poison damage. After 1 turn, the involucre explodes in a 10 ft. radius. All creatures in the radius make a DC 17 dexterity saving throw, taking 13 (3d8) necrotic damage or half as much on a success. A necromite is then birthed from the remains of the involucre. 

Tenacity. As a reaction to missing with a weapon attack, the mistress deals damage equal to its strength modifier (minimum 1) to the target of the attack.