Kuunganisha

Fiend Sight. Magical darkness doesn't impede the fiend's darkvision.

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

Regeneration. The fiend regains 1 hp at the start of its turn if it has at least 1 hp.

Will of the Master. The master of the kuunganisha can cast a spell through the familiar, using the fiend's senses to target the spell. The range limitations are treated as if the spell originated from the kuunganisha, not the master. The spell effect occurs on the kuunganisha's turn, though the master must cast the spell during the master's turn. Concentration spells must still be maintained by the master.

Multiattack. The kuunganisha makes one claw attack and one bite attack.

Bite. Melee Weapon Attack: +5 to hit, reach 5 ft., one target. Hit: 5 (1d4 + 3) piercing damage, and the target must succeed on a DC 13 Constitution saving throw or take 5 (2d4) poison damage and become poisoned for 1 minute. The target can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success.

Claw. Melee Weapon Attack: +5 to hit, reach 5 ft., one target. Hit: 8 (2d4 + 3) slashing damage.

Invisibility. The kuunganisha magically turns invisible until it attacks, or until its concentration ends (as if concentrating on a spell). Any equipment the fiend wears or carries becomes invisible with it.