Vrock

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

Multiattack. The vrock makes two attacks: one with its beak and one with its talons.

Beak. Melee Weapon Attack: +6 to hit, reach 5 ft., one target. Hit: 10 (2d6 + 3) piercing damage.

Talons. Melee Weapon Attack: +6 to hit, reach 5 ft., one target. Hit: 14 (2d10 + 3) slashing damage.

Spores (Recharge 6). A 15-foot-radius cloud of toxic spores extends out from the vrock. The spores spread around corners. Each creature in that area must succeed on a DC 14 Constitution saving throw or become poisoned. While poisoned in this way, a target takes 5 (1d10) poison damage at the start of each of its turns. A target can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success. Emptying a vial of holy water on the target also ends the effect on it.

Stunning Screech (1/Day). The vrock emits a horrific screech. Each creature within 20 feet of it that can hear it and that isn't a demon must succeed on a DC 14 Constitution saving throw or be stunned until the end of the vrock's next turn.

Variant: Summon Demon (1/Day). The demon chooses what to summon and attempts a magical summoning. A vrock has a 30 percent chance of summoning 2d4 dretches or one vrock. A summoned demon appears in an unoccupied space within 60 feet of its summoner, acts as an ally of its summoner, and can't summon other demons. It remains for 1 minute, until it or its summoner dies, or until its summoner dismisses it as an action.