Multiattack

The herald of darkness makes two Embrace Darkness or Shadow Sword attacks.

Embrace Darkness (Shadow Form Only)

Melee Spell Attack: +7 to hit, reach 0 ft., one creature in the herald's space. Hit: 18 (3d8 + 5) necrotic damage, and the target must succeed on a DC 15 Constitution saving throw or be paralyzed until the end of its next turn.

Shadow Sword (Fiend Form Only)

Melee Weapon Attack: +8 to hit, reach 10 ft., one target. Hit: 14 (2d8 + 5) slashing damage plus 9 (2d8) necrotic damage.

Majesty of the Abyss (Recharge 5-6)

The herald of darkness emits a sinister burst of infernal power. Each creature within 15 feet of the herald and that can see it must make a DC 15 Constitution saving throw. On a failure, a creature takes 27 (6d8) necrotic damage and is blinded for 1 minute. On a success, a creature takes half the damage and isn't blinded. A creature that fails the saving throw by 5 or more is also paralyzed until the end of its next turn. A blinded creature can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success.